https://wiki.diyfaq.org.uk/api.php?action=feedcontributions&user=John+Stumbles&feedformat=atomDIYWiki - User contributions [en]2024-03-29T13:33:53ZUser contributionsMediaWiki 1.35.9https://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=20605Motorised Valves2017-11-24T04:58:49Z<p>John Stumbles: /* Motor On / Motor Off (MOMO) valves */ move Sunvic to own section and expand</p>
<hr />
<div>This article is about motorised valves used in [[central heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the valve to the open position until the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring pulls the mechanism (and the motor) back, returning it to its original, closed, position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably ''the'' most common type and make of valve found in domestic CH systems. Note the flushing/override lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
There is a detailed explanation of the workings of these valves [[Three port mid position valve|here]].<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they active - typically when the system controls are calling for heat. In in the case of the mid position 3-port valve, they may also still consume power when all the calls for heat are satisfied (see suggested modification below to "fix" this. In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found [[Three port mid position valve|here]]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|Click for larger image]]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main [[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
====Alternate Y plan circuit====<br />
Wiki reader Anthony Ford, contributed the following design modification which circumvents the situation where a valve can remain powered for an extended period even when all the calls for heat are satisfied. The modification introduces an additional relay into the control wiring to allow the valve to spring return completely when all calls for heat are satisfied. <br />
<br />
[[image:AlternateYplanSchematic.gif|Click for larger image]]<br />
<br />
The relay used can be either a traditional coil based SPST device, or a modern solid state device, so long as the input is rated for operation at mains voltage, and the relay can switch an inductive load of a few amps. See the [[Extractor_fan_wiring#Using_relay_controls|Using relay controls section of this article]] for more information on providing noise and transient suppression when using relays in mains electrical systems. Alternatively, one can also get relays that include contact suppression and activation LEDs which can be useful in applications like this.<br />
<br />
====Alternate Y plan circuit, with indicators====<br />
In addition to the above, Anthony also submitted the following design modification to provide position indication:<br />
<br />
One of the criticisms of the traditional three port valve is that it does not include any form of indicator to show either its position or what heating demands are actually active at any given time. This makes diagnosing and troubleshooting problems with the heating system harder than they need be. The following variation of the above circuit not only includes the ability to turn the valve completely "off" when all demands are satisfied, but also allows the addition of indicator lamps to show what the heating demands actually are.The DPDT relay with the NO/NC contacts positioned in the wires as shown is necessary to prevent back feeds giving false indication. eg. If the hot water is satisfied but the central heating calling the orange wire from the valve would be live. In this state without the relay contact the CH calling light would be illuminated and also false indication that the HW is also calling.a similar situation exists with the HW satisfied indication.<br />
<br />
[[image:AlternateYplanSchematicWithIndicators.gif|Click for larger image]]<br />
[[image:CHDemandIndicator.jpg|thumb|right|Implementation of the above wiring setup showing neon diagnostic indicators. Click for larger image]]<br />
<br />
'''Description of operation'''<br />
<br />
The photograph on the right shows the valve indicator lights as installed on my system. They are wired into the adjacent 3 port valve junction box and connected as shown in the above diagram. <br />
<br />
The boxes housing the equipment are normal white plastic one gang surface socket outlet boxes. The top box houses the DPDT mains relay as shown in the diagram. The relay is an 8 pin plug in type. Under working conditions the box is fitted with a blanking plate. The box in the centre contains the Red, Amber and Green 240 volt neon indicators mounted on a drilled blanking plate. The connectors to the wiring are housed in this box.<br />
<br />
In my set up the red neon is CH calling, the amber neon is water calling, and the green is hot water satisfied/off.<br />
The box at the bottom (you can just see the top of it in the picture) houses the SPST relay shown in the drawing. This is also an eight pin plug in type. This relay ensures the spring return valve is "released" when the CH call is satisfied.<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the valve is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== Sunvic "EcoSmart" valves ====<br />
<br />
Normally MOMO valves have to be wired differently to spring-return valves. However [http://www.sunvic.co.uk/products/motorised-zone-valves/ Sunvic]'s "EcoSmart" valves incorporate control electronics which allow them to be wired (almost) identically to spring-return valves. <br />
<br />
The EcoSmart valves require power to move from one position to another. In a Y-plan system the 3-port valve always has power from the HW call or satisfied lines so this is not a problem but a spring-return 2-port valve only needs power applied across brown and blue wires to open, with orange and grey wires being connected to an isolated microswitch, so it doesn't matter if the orange and grey wires are swapped around, and the valve can be used electrically like a single-pole normally-open relay in unconventional control systems. Since the EcoSmart 2-port valve needs power to move to the closed position Sunvic's SZM1801 actuator requires a permanent live supply on its grey wire, with orange being a live-energised output when the valve is open. So it is important to check how a conventional spring-return 2-port valve is wired before replacing it with a Sunvic EcoSmart.<br />
<br />
Compared to Honeywell-type 3-port valves' 2 microswitches, one diode and 2 resistors Sunvic 3-port valves contain more electronics: two relays and 3 micro-switches, using two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which have 24V DC coils. These valves should be more reliable than spring return types since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly, and <br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components.<br />
<br />
However the electronics, in particular the high voltage rated capacitors, can be a source of failure, as described on Stephen Wozniak's [http://www.seered.co.uk/sunvic.htm website].<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring is not compatible with modern spring return 3-port valves; the Flow-share requires CH CALL and SAT and only HW CALL whereas spring-return types require only CH CALL but HW CALL and SAT.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=20604Motorised Valves2017-11-24T04:05:38Z<p>John Stumbles: /* 3-port */</p>
<hr />
<div>This article is about motorised valves used in [[central heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the valve to the open position until the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring pulls the mechanism (and the motor) back, returning it to its original, closed, position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably ''the'' most common type and make of valve found in domestic CH systems. Note the flushing/override lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
There is a detailed explanation of the workings of these valves [[Three port mid position valve|here]].<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they active - typically when the system controls are calling for heat. In in the case of the mid position 3-port valve, they may also still consume power when all the calls for heat are satisfied (see suggested modification below to "fix" this. In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found [[Three port mid position valve|here]]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|Click for larger image]]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main [[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
====Alternate Y plan circuit====<br />
Wiki reader Anthony Ford, contributed the following design modification which circumvents the situation where a valve can remain powered for an extended period even when all the calls for heat are satisfied. The modification introduces an additional relay into the control wiring to allow the valve to spring return completely when all calls for heat are satisfied. <br />
<br />
[[image:AlternateYplanSchematic.gif|Click for larger image]]<br />
<br />
The relay used can be either a traditional coil based SPST device, or a modern solid state device, so long as the input is rated for operation at mains voltage, and the relay can switch an inductive load of a few amps. See the [[Extractor_fan_wiring#Using_relay_controls|Using relay controls section of this article]] for more information on providing noise and transient suppression when using relays in mains electrical systems. Alternatively, one can also get relays that include contact suppression and activation LEDs which can be useful in applications like this.<br />
<br />
====Alternate Y plan circuit, with indicators====<br />
In addition to the above, Anthony also submitted the following design modification to provide position indication:<br />
<br />
One of the criticisms of the traditional three port valve is that it does not include any form of indicator to show either its position or what heating demands are actually active at any given time. This makes diagnosing and troubleshooting problems with the heating system harder than they need be. The following variation of the above circuit not only includes the ability to turn the valve completely "off" when all demands are satisfied, but also allows the addition of indicator lamps to show what the heating demands actually are.The DPDT relay with the NO/NC contacts positioned in the wires as shown is necessary to prevent back feeds giving false indication. eg. If the hot water is satisfied but the central heating calling the orange wire from the valve would be live. In this state without the relay contact the CH calling light would be illuminated and also false indication that the HW is also calling.a similar situation exists with the HW satisfied indication.<br />
<br />
[[image:AlternateYplanSchematicWithIndicators.gif|Click for larger image]]<br />
[[image:CHDemandIndicator.jpg|thumb|right|Implementation of the above wiring setup showing neon diagnostic indicators. Click for larger image]]<br />
<br />
'''Description of operation'''<br />
<br />
The photograph on the right shows the valve indicator lights as installed on my system. They are wired into the adjacent 3 port valve junction box and connected as shown in the above diagram. <br />
<br />
The boxes housing the equipment are normal white plastic one gang surface socket outlet boxes. The top box houses the DPDT mains relay as shown in the diagram. The relay is an 8 pin plug in type. Under working conditions the box is fitted with a blanking plate. The box in the centre contains the Red, Amber and Green 240 volt neon indicators mounted on a drilled blanking plate. The connectors to the wiring are housed in this box.<br />
<br />
In my set up the red neon is CH calling, the amber neon is water calling, and the green is hot water satisfied/off.<br />
The box at the bottom (you can just see the top of it in the picture) houses the SPST relay shown in the drawing. This is also an eight pin plug in type. This relay ensures the spring return valve is "released" when the CH call is satisfied.<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the valve is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV 2304 valves are motor-on/motor-off (MOMO) types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring is not compatible with modern spring return 3-port valves; the Flow-share requires CH CALL and SAT and only HW CALL whereas spring-return types require only CH CALL but HW CALL and SAT.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=20603Motorised Valves2017-11-24T03:59:18Z<p>John Stumbles: /* Alternate Y plan circuit */ remove dead link to relay with snubber on CPC site which says device no longer manufactured</p>
<hr />
<div>This article is about motorised valves used in [[central heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the valve to the open position until the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring pulls the mechanism (and the motor) back, returning it to its original, closed, position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably ''the'' most common type and make of valve found in domestic CH systems. Note the flushing/override lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
There is a detailed explanation of the workings of these valves [[Three port mid position valve|here]].<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they active - typically when the system controls are calling for heat. In in the case of the mid position 3-port valve, they may also still consume power when all the calls for heat are satisfied (see suggested modification below to "fix" this. In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found [[Three port mid position valve|here]]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|Click for larger image]]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main [[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
====Alternate Y plan circuit====<br />
Wiki reader Anthony Ford, contributed the following design modification which circumvents the situation where a valve can remain powered for an extended period even when all the calls for heat are satisfied. The modification introduces an additional relay into the control wiring to allow the valve to spring return completely when all calls for heat are satisfied. <br />
<br />
[[image:AlternateYplanSchematic.gif|Click for larger image]]<br />
<br />
The relay used can be either a traditional coil based SPST device, or a modern solid state device, so long as the input is rated for operation at mains voltage, and the relay can switch an inductive load of a few amps. See the [[Extractor_fan_wiring#Using_relay_controls|Using relay controls section of this article]] for more information on providing noise and transient suppression when using relays in mains electrical systems. Alternatively, one can also get relays that include contact suppression and activation LEDs which can be useful in applications like this.<br />
<br />
====Alternate Y plan circuit, with indicators====<br />
In addition to the above, Anthony also submitted the following design modification to provide position indication:<br />
<br />
One of the criticisms of the traditional three port valve is that it does not include any form of indicator to show either its position or what heating demands are actually active at any given time. This makes diagnosing and troubleshooting problems with the heating system harder than they need be. The following variation of the above circuit not only includes the ability to turn the valve completely "off" when all demands are satisfied, but also allows the addition of indicator lamps to show what the heating demands actually are.The DPDT relay with the NO/NC contacts positioned in the wires as shown is necessary to prevent back feeds giving false indication. eg. If the hot water is satisfied but the central heating calling the orange wire from the valve would be live. In this state without the relay contact the CH calling light would be illuminated and also false indication that the HW is also calling.a similar situation exists with the HW satisfied indication.<br />
<br />
[[image:AlternateYplanSchematicWithIndicators.gif|Click for larger image]]<br />
[[image:CHDemandIndicator.jpg|thumb|right|Implementation of the above wiring setup showing neon diagnostic indicators. Click for larger image]]<br />
<br />
'''Description of operation'''<br />
<br />
The photograph on the right shows the valve indicator lights as installed on my system. They are wired into the adjacent 3 port valve junction box and connected as shown in the above diagram. <br />
<br />
The boxes housing the equipment are normal white plastic one gang surface socket outlet boxes. The top box houses the DPDT mains relay as shown in the diagram. The relay is an 8 pin plug in type. Under working conditions the box is fitted with a blanking plate. The box in the centre contains the Red, Amber and Green 240 volt neon indicators mounted on a drilled blanking plate. The connectors to the wiring are housed in this box.<br />
<br />
In my set up the red neon is CH calling, the amber neon is water calling, and the green is hot water satisfied/off.<br />
The box at the bottom (you can just see the top of it in the picture) houses the SPST relay shown in the drawing. This is also an eight pin plug in type. This relay ensures the spring return valve is "released" when the CH call is satisfied.<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the valve is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-on/motor-off (MOMO) types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring is not compatible with modern spring return 3-port valves; the Flow-share requires CH CALL and SAT and only HW CALL whereas spring-return types require only CH CALL but HW CALL and SAT.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Example_article&diff=19915Example article2016-10-15T12:01:14Z<p>John Stumbles: /* Level 4 Sub-sub-subheading */ add levels showing how attempt to create level 7 fails</p>
<hr />
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[[Category:Wiki]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Example_article&diff=19914Example article2016-10-15T11:59:37Z<p>John Stumbles: Add Lorem ipsum text to show effect on margins of blockquote etc</p>
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[[Category:Wiki]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Central_heating_design&diff=18605Central heating design2014-05-03T19:18:42Z<p>John Stumbles: /* Whole house/boiler sizing */ revert & correct idhe->idhee, remove EST calculator</p>
<hr />
<div>This article is about [[Central heating]] systems using hot water as a heat-carrying medium. <br />
(Warm-air systems are sometimes found in the UK but their design and installation is not covered here. There is a discussion on updating existing warm-air systems [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/cd973db3a3604624? here])<br />
<br />
The article is intended as a guide to:<br />
* choosing a design for, and installing a new central heating system<br />
* understanding how an existing system is designed, for the purposes of maintaining and fault-finding<br />
<br />
There are separate articles about:<br />
* [[Central heating operation]] for help maintaining a working CH system<br />
* [[Central Heating Repair]] for diagnosing and fixing a faulty system.<br />
<br />
'''''Parts of this article are in skeleton form with main points listed but needing to be expanded'''''<br />
<br />
== Heat requirements ==<br />
In order to get a heating system which works effectively and economically it is important to calculate how much heating power will be required, into the building as a whole (in order to calculate the required size for the boiler or other heat source) and into each room (to calculate sizes of radiators or other heat emitters).<br />
<br />
=== Whole house/boiler sizing ===<br />
For boiler sizing there is a relatively simple yet sufficiently accurate calculation known as the whole-house boiler sizing method. The method is described in the<br />
* [http://www.est.org.uk/uploads/documents/housingbuildings/ce54.pdf Energy Saving Trust worksheet] (PDF)<br />
An online calculator implementing the method is available at:<br />
* [http://www.idhee.org.uk/calculator.html IDHE (Institute of Domestic Heating & Environmental Engineers) calculator]<br />
A spreadsheet implementing the calculator is available at:<br />
* [http://yaph.co.uk/heating/boiler_sizing.xls YAPH]<br />
The spreadsheet allows easy what-if calculations showing the effect of, say, cavity wall insulation on the house heating requirements.<br />
<br />
=== Heatloss/radiator sizing ===<br />
For calculating the heat requirements of rooms an elemental approach is taken.<br />
# The area of walls, windows, doors, floor and ceilings is calculated<br />
# U-values for the materials of these elements are found from tables<br />
# Temperature differences across the elements are multiplied by the above figures to calculate total ''fabric'' loss<br />
# The volume of the room is calculated<br />
# The number of air-changes per hour expected for the room is found from a table<br />
# The above two figures are multiplied together with a factor for the heat capacity of air to calculate total ''ventilation'' loss<br />
# The fabric and ventilation losses are added to calculate the total heat requirement of the room, and therefore the size of radiator or other heat-emitter(s) required.<br />
<br />
A (Microsoft Windows) computer program implementing this method is the<br />
* [http://www.quinn-radiators.co.uk/downloads_heatloss.php Barlo heatloss calculator]<br />
<br />
''* Discuss + links to energy conservation articles''<br />
<br />
== Heat Sources ==<br />
<br />
=== Fuels ===<br />
<br />
The most popular fuels for central heating systems are (in order of increasing expense):<br />
# '''Natural Gas'''<br />
# '''Oil'''<br />
# '''LPG''' (Liquefied Petroleum Gas). '''Propane''' and '''Butane''' are LPGs but for heating propane is mostly used. It is often known generically as "Calor" gas (in the same way that vacuum cleaners are known as "Hoovers").<br />
# '''Electricity''' can be used for central heating systems but where it is used for heating it is generally found used with storage heaters using off-peak rate electricity. Where no other fuel is available a system using a [[heat bank]] heated by off-peak electricity with [[Underfloor Heating]] or radiators is likely to be more economical to run than one using storage heaters or any sort of peak-rate heaters. An example of such a system is the "[http://www.gasapplianceguide.co.uk/gledhill_electramate.htm Electramate]" made by [http://www.gledhill.net/ Gledhill]. This is a ready-made package, but similar systems can be designed using other manufacturers' components.<br />
<br />
* '''solid fuel'''s - coal, anthracite etc, and wood or woodchips - are sometimes used to contribute to space and/or water heating. Nowadays they are not usually used as main fuels since most domestic appliances for using them cannot be automatically fed and regulated.<br />
<br />
'''Renewable''' sources such as:<br />
* '''solar thermal'''<br />
* '''geothermal'''<br />
are also increasingly found contributing to heating systems rather than providing sole energy supply.<br />
<br />
=== Appliances ===<br />
<br />
==== Boilers ====<br />
The most common appliances for supplying heat are '''boilers''' using natural gas, oil or LPG to heat "'''primary'''" water. Primary water is water intended for heating rooms via radiators etc or heating "'''secondary'''" water for washing etc (see '''[[Domestic Hot Water|DHW]]'''). Some boilers - known as '''combi''' boilers - heat DHW directly.<br />
<br />
''For further discussion of types of boiler, combi/conventional choice etc see:<br />
*[[Boiler]]s<br />
*[http://www.makewrite.demon.co.uk/BoilerChoice.html Ed's Boiler Choice FAQ]''<br />
<br />
Electric boilers perform the same function as non-combi boilers using electricity. They can be expected to have very high running costs compared to natural gas, oil or LPG boilers.<br />
<br />
==== Ranges ====<br />
'''Ranges''' e.g. '''Aga'''s and '''Rayburn'''s usually heat DHW as a by-product of their cooking functions. They may use natural gas, oil, LPG or solid fuels.<br />
<br />
'''Combined range/boilers''' appear outwardly almost identical to ranges but contain a separate central heating boiler sharing the flue of the cooking range. They may use natural gas, oil or LPG. They are generally non-condensing appliances and therefore less efficient than current central heating boilers (one exception being the [http://www.rayburn-web.co.uk/57_266.htm Rayburn 480 CD] which has a condensing boiler section: this gas-only appliance is only available with a balanced flue).<br />
<br />
==== CHP ====<br />
'''Combined Heat and Power (CHP)''' generators (e.g. '''[http://www.microgen.com/ Microgen]''', '''[http://www.whispergen.com/ Whispergen]''') generate electrical power whilst heating primary water.<br />
<br />
They generate electricity with much lower efficiency than fossil fuel generated electricity supplied by conventional central power stations, but they only generate when heat is wanted, which means all the heat and electricity output is used. This makes the overall picture more efficient than a central power station, where over half the input energy is wasted as heat. So overall the method works out more energy efficient.<br />
<br />
CHP requires non-trivial arrangements for connection into the domestic electricity supply, and financial and administrative arrangements to sell surplus electricity back to the supplier.<br />
<br />
CHP is a well established technology for large facilities, but domestic CHP generators are not readily available in the UK at present (Feb 2007), partly due to concerns about some aspects of the systems and lack of a solid proven track record of domestic CHP or the products on offer.<br />
<br />
==== Solid-fuel back-boilers ====<br />
Traditional coal fires or more modern wood-burning stoves with back boilers can contribute to domestic space or water heating. Their heating output is sometimes combined with that of a main heating boiler by means of a [http://www.dunsleyheat.co.uk/linkupsys.htm Dunsley Neutraliser], although thermal stores can also be used.<br />
<br />
==== Renewable sources ====<br />
<br />
'''Solar thermal panels''' are usually used to provide [[Domestic Hot Water]] (If considering this technology one might also investigate solar warm air systems which may give better energy returns for a given cost: see [[Solar Thermal]].)<br />
<br />
'''Ground-source heat pumps''' provide energy at lower temperatures than are required for DHW and are generally used in space heating systems, often with under-floor heating which can make better use of the lower temperatures generated.<br />
<br />
Both systems, as well as [[Drain Heat Exchanger|waste water heat recovery]], can be used with thermal stores, combining their output with other systems including conventional boilers and/or electric backup heaters to provide space heating, via UFH and radiators, and DHW.<br />
<br />
''' Air-source Heat Pumps ''' - similar benefits as ground-source heat pumps and easier to install; however in locating these units, the potential noise of the fan must be taken into account as some people are very sensitive to such noise, especially at night.<br />
<br />
== Heat Emitters ==<br />
'''''Emitters''' are means of heating spaces: radiators, under-floor heating etc.''<br />
<br />
=== Radiators ===<br />
''"Radiators" actually emit heat mostly via convection rather than radiation: they heat the air which heats the fabric of the room and its occupants.''<br />
<br />
They come in a number of types -- standard panel radiators, Low Surface Temperature (LST), "designer" radiators and towel warmers -- and shapes, sizes and colours/finishes. Radiators must be chosen and located so as to provide sufficient output to heat the spaces they are installed into.<br />
<br />
There is more detail in the article:<br />
* [[Central Heating Radiators]]<br />
<br />
=== Fan-assisted heaters ===<br />
''These types use forced convection, compared to natural convection employed by radiators.''<br />
<br />
Sometimes known as kickspace heaters, these have a fan to distribute air warmed by a water-to-air heat exchanger (typically tubes with fins attached) which transfer heat from the central heating primary water.<br />
<br />
* particularly suitable for small rooms with limited wall space for rads (e.g. kitchen) or too-high heat-loss/floor-area ratio for UFH (e.g. bathroom)<br />
* fast warm-up<br />
* less localised heating effect than radiators; can be effective at heating larger areas<br />
* may feel uncomfortably cold when shut off by thermostat (like electric fan heaters)<br />
* may be too noisy for domestic use in lounges and bedrooms<br />
<br />
=== Underfloor ===<br />
<br />
''This gives radiant heat which warms occupants and fabric directly rather than warming the air.''<br />
<br />
* Requires less total heat output (figures of around 20% are quoted) for a given comfort level compared to radiator-based systems.<br />
* Tends to give warmer feet and cooler heads giving a more comfortable, less stuffy feeling.<br />
* Good for heating large spaces where it would be hard to install sufficient radiators, and spaces with high ceilings e.g. halls where the output of radiators would be lost to the higher parts of the room.<br />
* Limited heat output due to limitation on maximum comfortable floor temperatures which may be insufficient for small rooms with large heat requirements & large losses e.g. bathrooms (although the warmer floors, in conjunction with extra heating from radiators or kick-space heaters, can make for a more comfortable room than one with a cold floor).<br />
* Heat output dependent on floor coverings which need to be chosen to work with the UFH system.<br />
* Slower to heat & cool than radiator based systems, so need better control systems.<br />
* Slow thermal response leads to lower overall efficiency for spaces occupied for relatively short periods, due to the heat lost during the longer warm-up and cool-down periods.<br />
* Hydronic (hot-water) systems generally require lower water temperatures than radiator systems leading to extra complexity and expense (extra pump & thermostatic mixing valve) to run in mixed system with radiators.<br />
* The lower water temperatures required by pure UFH systems enable condensing boilers, solar collectors and heat pumps to operate more efficiently than with radiator-based systems.<br />
* Generally expensive & disruptive to retro-fit to existing building due to need to remove & relay floors (or possibly ceilings below for upper-floor installations).<br />
* Electric UFH is cheaper to install but has higher running costs: popular choice for small bath or shower rooms.<br />
More on [[Underfloor Heating]]<br />
<br />
=== Other radiant ===<br />
Walls can also be used for radiant heating. Usually this is acheived by embedding heating pipework into a solid wall surface. A discussion of the possibility of heating via stud walls can be found [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/3fe720e4cfce3a6d/c2183341d4849b0e here].<br />
<br />
Heating ceilings has the obvious disadvantage of unwanted heat loss upwards; even so one (singularly ineffective) installation is known to [[User:John Stumbles|one of the authors]].<br />
<br />
== Filling arrangements: sealed or vented ==<br />
<br />
The traditional arrangement for maintaining a body of water in the system comprises a '''feed and expansion''' (aka '''header''') tank above the highest point of the system. The tank is kept topped up by a float valve similar to that in a main cold water storage tank or WC cistern.<br />
<br />
Modern systems are usually '''sealed''' with water introduced to the system by a temporary filling hose (or special key-operated device built-in to the boiler). More info can be found in [http://www.makewrite.demon.co.uk/SealedCH.html Ed Sirett's Sealed System FAQ].<br />
<br />
For a completely new system a sealed arrangement is generally preferred, unless it is wished to use a directly heated [[Thermal Store]]. Where an old and poorly-constructed existing system is converted to sealed operation there is the possibility of minor leaks from old radiator valves and poorly-made compression joints leading to relatively rapid loss of pressure and the need to top up the system frequently. For this reason if there is no compelling requirement to convert the system it may be better left alone. Conversely if an open vented system suffers from scaling up of the feed pipe, pumping over of the vent pipe into the feed and expansion tank, microbial sludge growth in the F&E tank or air air-locks when filling up it may be worth converting to sealed operation (provided the boiler is a type for which this is permitted).<br />
<br />
== Configuration: Controls and Zoning ==<br />
<br />
An important aspect of the way a heating system is designed is the way heating is divided into physical zones, and the controls used to regulate heating. These are discussed in a separate article:<br />
* '''[[Central Heating Controls and Zoning]]'''<br />
<br />
== Pipework ==<br />
=== Pipework materials ===<br />
==== Copper ====<br />
<br />
Traditional material.<br />
<br />
Available in various grades and sizes. Those found in domestic CH installations are:<br />
<br />
* Rigid ("Table X") in small-bore sizes: 28mm, 22mm, 15mm<br />
* Fully-annealed (soft) ("Table Y") in micro-bore sizes: 10mm, 8mm<br />
<br />
Features:<br />
* Material usually more expensive than plastics<br />
* Available in lengths 1m, 2m, 3m (also 6m?). 2m and 3m are most common.<br />
* More time-consuming to install<br />
* Requires more lifting of flooring when retro-fitting to existing building<br />
* Small-bore pipes must usually be run in notches in the top of joists: susceptible to damage by nailing and contrary to building regulations.<br />
* Micro-bore pipes may be threaded through holes in joists out of reach of nailing<br />
* Micro-bore pipe may be "cabled" through floor and wall spaces with less disruption in existing building<br />
* May be noisy (e.g. clicking noises) as pipes expand & contract when heating & cooling<br />
* Surface runs can be done neatly avoiding need for boxing-in in certain locations<br />
* Can be joined with solder, compression or push-fit fittings<br />
* Micro-bore may be bent by hand (with external spring) or by small machine for neater bends<br />
* Small-bore may be bent by hand with spring for 15mm (and possibly 22mm if pipe annealed or fitter very strong)<br />
* Small-bore may be bent with large hand-held machine for 15 & 22mm, larger machine on stand for 28mm<br />
<br />
==== Plastic ====<br />
<br />
Some older installations using small-bore (15-28mm) pipework in PVC and ABS may be found but these materials are no longer used for CH pipework.<br />
<br />
Moderm materials (used for last 2 decades or so in UK) are<br />
* PB (Polybutylene)<br />
* PEX (Polyethylene cross-linked)<br />
<br />
Sizes available are:<br />
* 28mm<br />
* 22mm<br />
* 15mm<br />
* 10mm<br />
<br />
Features:<br />
* Pipework usually cheaper than copper<br />
* Pipe available in long rolls e.g. 25m, 50m and 100m<br />
* Easier & quicker to install than rigid pipe<br />
* Pipe may be "cabled" with minimum lifting of flooring in existing building<br />
* Pipes may be run through holes in joists out of reach of nailing<br />
* Pipes expand and sag when hot requiring boxing-in if run on surface<br />
* Can be joined with compression and push-fit fittings.<br />
* Long runs possible with bends in pipework and fewer fittings<br />
<br />
===== Barrier and non-barrier =====<br />
Conventional Wisdom is that only barrier pipe should be used for CH systems as the metallic barrier layer prevents oxygen diffusing through the plastic walls of the pipe into the primary water and causing corrosion in ferrous and possibly other metallic parts of the system - boilers, radiators etc. However [http://www.hep2o.co.uk/ Hepworth Plumbing Products] have stated <br />
in the uk-d-i-y newsgroup that:<br />
<blockquote><br />
If Hep2O Standard pipe has been installed in accordance with our<br />
instructions in a central heating system and one of the recommended<br />
inhibitors used there is no technical reason why it should not continue to<br />
give good service for many decades. [[http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/70540dffa9cf9f4b/34103c153f976739?rnum=1&q=If+Hep2O+Standard+pipe+has+been+installed+in+accordance+with+our&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2F70540dffa9cf9f4b%2Fe2db7ffcad95adb1%3Flnk%3Dst%26q%3DIf+Hep2O+Standard+pipe+has+been+installed+in+accordance+with+our%26rnum%3D1%26#doc_e2db7ffcad95adb1]]<br />
<br />
</blockquote><br />
and<br />
<blockquote><br />
It is now considered by British Gas that central heating systems that<br />
include plastics pipe manufactured to the appropriate British Standard<br />
(such as Hep2O) do not represent a potential corrosion problem from<br />
oxygen ingress where the system water includes an adequate strength of<br />
inhibitor. This applies equally to Barrier and Non-Barrier pipes. [[http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/ff1a4f63c1facf9e/4254068524cd8c4c?rnum=1&q=hepworth+barrier+pipe&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fff1a4f63c1facf9e%2Ff343d48ec0be74b2%3Flnk%3Dst%26q%3Dhepworth+barrier+pipe%26rnum%3D2%26#doc_f343d48ec0be74b2]]<br />
<br />
</blockquote><br />
<br />
However in real life not all central heating systems have effective corrosion inhibition at all times, so barrier pipe is still the preferred option.<br />
<br />
==== Tails ====<br />
<br />
Even in a system using plastic pipe for the main pipe runs the boiler manufacturer usually requires the first 600mm or 1m of pipework connected to the boiler to be in copper.<br />
<br />
Also many installers and/or clients prefer copper tails to radiators rather than plastic. For "designer" radiators or towel radiators in bathrooms chromed radiator tails are often preferred. Since chrome is very hard it is necessary to remove the chrome from the part of the tail pipe being connected into a push-fit fitting since the grab ring of the fitting may not bite securely into the chrome and the fitting may become detatched. It is also necessary to remove the chrome when connecting into a solder fitting since solder may not adhere properly to chrome. If using a compression fitting a brass olive is preferable to a copper one since the olive has to slightly compress the pipework to secure the fitting and the chrome may be too hard for a soft copper olive to acheive the necessary pressure.<br />
<br />
=== pipework layout ===<br />
==== pipe sizes v. heat-carrying capacities + noise ====<br />
<br />
==== Single pipe loop ====<br />
<br />
Obsolete - not used for current designs but found in some old installations.<br />
<br />
Single pipe means that radiators are plumbed in series. The problem is that as water passes through each radiator, it loses heat, so radiators at the far end of the chain have to be oversized, and run at reduced temps.<br />
<br />
Where necessary to extend (add extra rads) can either add new rad into existing loop (allowing extra size for rad if at cool end of loop) or, especially if several new rads to be added, divide system and add a seperate 2-pipe loop - perhaps as a seperate zone if it makes sense.<br />
<br />
Single pipe systems may underperform, as heating expectations are higher now than they were when these old systems were installed. Replumbing the radiators in parallel is a logical option, but there is a simpler and cheaper way to improve total heat output to some extent, and that is to increase pumping rate. The faster the pumping, the less temp loss occurs along the chain. A more powerful or 2nd pump can thus be a low cost way to increase system output.<br />
<br />
==== Tree: trunk + branch ====<br />
A good pipework arrangement has 'trunk' pipes from the boiler in 22mm (or 28mm depending on the output of the boiler and the manufacturer's instructions) with branches in 15mm (or microbore: 10mm or 8mm) to individual radiators. Pipe sizes can be stepped down from trunks through branches e.g. <br />
<br />
[[Image:Trunk-branch.gif]]<br />
<br />
==== Microbore ====<br />
<br />
The topology of a microbore installation is usually a tree with trunks of 22mm and branches of 10mm and/or 8mm pipework, and is inherently well-balanced.<br />
<br />
The fully-annealed ("Table Y") copper pipe (or flexible plastic pipe) used for the microbore sections can be bent and threaded through stud walls and joists unlike rigid copper in small-bore sizes.<br />
<br />
Some clients may prefer to have 15mm tails to radiators (joined to microbore under the floor or in the wall) for the sake of appearance.<br />
<br />
There is an article on [[Fitting_TRVs_to_Microbore|retro-fitting 15mm radiator valves to microbore]].<br />
<br />
Limited power throughput (2.5kW-ish)<br />
<br />
Narrow bore is more vulnerable to sludge.<br />
<br />
==== Dual loop ====<br />
inherently balanced but rarely practicable<br />
<br />
==== Random ====<br />
An arrangement with radiators connected with widely varying lengths of narrow-bore pipework is bad for balancing but sometimes necessary especially when extending an existing system where access under floors etc is limited.<br />
<br />
== Installation ==<br />
=== Routing ===<br />
The choice of routes for the pipework may have to incorporate a number of criteria. These may be aesthetic, cost or performance based. For instance, the performance considerations will urge you avoid routing through unheated spaces or a zone differing from the one to be heated. The cold space below a suspended ground floor is not a natural performance choice and requires effective insulation but is an overwhelmingly good choice from the cost and aesthetic aspects.<br />
<br />
Typically there are general approaches depending on the structure of the floors.<br />
* All floor(s) suspended: Main pipes run vertically between floor(s) in one place (often a corner near the boiler). Plastic pipe is a great choice as it can be cabled through joists and readily installed in runs between joists; it is also out of sight, has fewer joints and lower heat losses. Copper/chrome tails emerge through floor to supply radiator from below.<br />
* Ground floor is solid other floor(s) are suspended: The upper floors or even the loft space (for a bungalow) are used as above and also to supply the radiators in rooms below. Groups of one to three radiators (or perhaps more) are supplied from above by a pair of pipes. Each group will need a drain off point. Pipes drops are on show but can be hidden in a duct but this can make a feature out of a necessity, there will still be runs under the radiator.<br />
* All solid floors and ceiling: Copper pipes are run round at skirting board height from room to room, going through internal walls as needed. This usually leads to a inferior layout topology so needing extra care to balance the system. The entrance door is often an obstacle; it can be unsightly to go over and across and down, and that leads to the needs for air bleed points, ideally at the top of each down flowing pipe, this is a further draw back. It is often best to bite the bullet and dig the concrete up to cross under the doorway and accept that such sites have difficulties. <br />
* New build: Apart from the possibility of underfloor heating there is also the oportunity to install microbore plastic behind dry lining boards.<br />
<br />
* installation in solid floor<br />
<br />
==== Joist Notching ====<br />
Building regs impose restriction on the places and sizes for notches and holes in joists. <br />
Notches must be no more than 12.5% of joist depth installed between 10% and 25% along the spans length. <br />
The best way to cross joists is through holes bored in the middle of joists. Microbore can be cabled through, about 4 or 5 joists seems to be the maximum number that can be crossed by any single length. Flexible plastic pipe is a very welcome material in these cases, even then a good right angled joist boring drill or cordless equivalent is a must for this part of the job. Rigid pipework has to be installed in notches, which should be placed in the middle of the floor board. <br />
==== Drain-off points ====<br />
It is certainly good practice, if not manadatory, to install drain off points on the lowest points of the pipework.<br />
Ideally the best place is outside over a gully. Some radiator valves include a built in drain tap. There are two types of fittings on is known as heavy and light pattern. The heavy type have a seal around the spindle they are a little less messy when in use. There is no reason why you could not use ball-o-fix service isolators although this does not seem to be common practice. <br />
<br />
* plastic v. copper or chromed pipetails<br />
** play in tails<br />
* pressure testing<br />
* flushing<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Central_heating_design&diff=18604Central heating design2014-05-03T19:16:55Z<p>John Stumbles: Reverted edits by John Stumbles (talk) to last revision by NT</p>
<hr />
<div>This article is about [[Central heating]] systems using hot water as a heat-carrying medium. <br />
(Warm-air systems are sometimes found in the UK but their design and installation is not covered here. There is a discussion on updating existing warm-air systems [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/cd973db3a3604624? here])<br />
<br />
The article is intended as a guide to:<br />
* choosing a design for, and installing a new central heating system<br />
* understanding how an existing system is designed, for the purposes of maintaining and fault-finding<br />
<br />
There are separate articles about:<br />
* [[Central heating operation]] for help maintaining a working CH system<br />
* [[Central Heating Repair]] for diagnosing and fixing a faulty system.<br />
<br />
'''''Parts of this article are in skeleton form with main points listed but needing to be expanded'''''<br />
<br />
== Heat requirements ==<br />
In order to get a heating system which works effectively and economically it is important to calculate how much heating power will be required, into the building as a whole (in order to calculate the required size for the boiler or other heat source) and into each room (to calculate sizes of radiators or other heat emitters).<br />
<br />
=== Whole house/boiler sizing ===<br />
For boiler sizing there is a relatively simple yet sufficiently accurate calculation known as the whole-house boiler sizing method. The method is described in the<br />
* [http://www.est.org.uk/uploads/documents/housingbuildings/ce54.pdf Energy Saving Trust worksheet] (PDF)<br />
Online calculators implementing the method are available at:<br />
* [http://www.idhe.org.uk/calculator.html IDHE (Institute of Domestic Heating & Environmental Engineers) calculator] ''(site not available - 10th July 2008)''<br />
* [http://www.est.org.uk/housingbuildings/calculators/boilersizing/ Energy Saving Trust calculator] This calculator is rather cumbersome to use '''and is incorrect for flats (it doesn't discount roof losses)'''<br />
A spreadsheet implementing the calculator is available at:<br />
* [http://yaph.co.uk/heating/boiler_sizing.xls YAPH]<br />
The spreadsheet allows easy what-if calculations showing the effect of, say, cavity wall insulation on the house heating requirements.<br />
<br />
=== Heatloss/radiator sizing ===<br />
For calculating the heat requirements of rooms an elemental approach is taken.<br />
# The area of walls, windows, doors, floor and ceilings is calculated<br />
# U-values for the materials of these elements are found from tables<br />
# Temperature differences across the elements are multiplied by the above figures to calculate total ''fabric'' loss<br />
# The volume of the room is calculated<br />
# The number of air-changes per hour expected for the room is found from a table<br />
# The above two figures are multiplied together with a factor for the heat capacity of air to calculate total ''ventilation'' loss<br />
# The fabric and ventilation losses are added to calculate the total heat requirement of the room, and therefore the size of radiator or other heat-emitter(s) required.<br />
<br />
A (Microsoft Windows) computer program implementing this method is the<br />
* [http://www.quinn-radiators.co.uk/downloads_heatloss.php Barlo heatloss calculator]<br />
<br />
''* Discuss + links to energy conservation articles''<br />
<br />
== Heat Sources ==<br />
<br />
=== Fuels ===<br />
<br />
The most popular fuels for central heating systems are (in order of increasing expense):<br />
# '''Natural Gas'''<br />
# '''Oil'''<br />
# '''LPG''' (Liquefied Petroleum Gas). '''Propane''' and '''Butane''' are LPGs but for heating propane is mostly used. It is often known generically as "Calor" gas (in the same way that vacuum cleaners are known as "Hoovers").<br />
# '''Electricity''' can be used for central heating systems but where it is used for heating it is generally found used with storage heaters using off-peak rate electricity. Where no other fuel is available a system using a [[heat bank]] heated by off-peak electricity with [[Underfloor Heating]] or radiators is likely to be more economical to run than one using storage heaters or any sort of peak-rate heaters. An example of such a system is the "[http://www.gasapplianceguide.co.uk/gledhill_electramate.htm Electramate]" made by [http://www.gledhill.net/ Gledhill]. This is a ready-made package, but similar systems can be designed using other manufacturers' components.<br />
<br />
* '''solid fuel'''s - coal, anthracite etc, and wood or woodchips - are sometimes used to contribute to space and/or water heating. Nowadays they are not usually used as main fuels since most domestic appliances for using them cannot be automatically fed and regulated.<br />
<br />
'''Renewable''' sources such as:<br />
* '''solar thermal'''<br />
* '''geothermal'''<br />
are also increasingly found contributing to heating systems rather than providing sole energy supply.<br />
<br />
=== Appliances ===<br />
<br />
==== Boilers ====<br />
The most common appliances for supplying heat are '''boilers''' using natural gas, oil or LPG to heat "'''primary'''" water. Primary water is water intended for heating rooms via radiators etc or heating "'''secondary'''" water for washing etc (see '''[[Domestic Hot Water|DHW]]'''). Some boilers - known as '''combi''' boilers - heat DHW directly.<br />
<br />
''For further discussion of types of boiler, combi/conventional choice etc see:<br />
*[[Boiler]]s<br />
*[http://www.makewrite.demon.co.uk/BoilerChoice.html Ed's Boiler Choice FAQ]''<br />
<br />
Electric boilers perform the same function as non-combi boilers using electricity. They can be expected to have very high running costs compared to natural gas, oil or LPG boilers.<br />
<br />
==== Ranges ====<br />
'''Ranges''' e.g. '''Aga'''s and '''Rayburn'''s usually heat DHW as a by-product of their cooking functions. They may use natural gas, oil, LPG or solid fuels.<br />
<br />
'''Combined range/boilers''' appear outwardly almost identical to ranges but contain a separate central heating boiler sharing the flue of the cooking range. They may use natural gas, oil or LPG. They are generally non-condensing appliances and therefore less efficient than current central heating boilers (one exception being the [http://www.rayburn-web.co.uk/57_266.htm Rayburn 480 CD] which has a condensing boiler section: this gas-only appliance is only available with a balanced flue).<br />
<br />
==== CHP ====<br />
'''Combined Heat and Power (CHP)''' generators (e.g. '''[http://www.microgen.com/ Microgen]''', '''[http://www.whispergen.com/ Whispergen]''') generate electrical power whilst heating primary water.<br />
<br />
They generate electricity with much lower efficiency than fossil fuel generated electricity supplied by conventional central power stations, but they only generate when heat is wanted, which means all the heat and electricity output is used. This makes the overall picture more efficient than a central power station, where over half the input energy is wasted as heat. So overall the method works out more energy efficient.<br />
<br />
CHP requires non-trivial arrangements for connection into the domestic electricity supply, and financial and administrative arrangements to sell surplus electricity back to the supplier.<br />
<br />
CHP is a well established technology for large facilities, but domestic CHP generators are not readily available in the UK at present (Feb 2007), partly due to concerns about some aspects of the systems and lack of a solid proven track record of domestic CHP or the products on offer.<br />
<br />
==== Solid-fuel back-boilers ====<br />
Traditional coal fires or more modern wood-burning stoves with back boilers can contribute to domestic space or water heating. Their heating output is sometimes combined with that of a main heating boiler by means of a [http://www.dunsleyheat.co.uk/linkupsys.htm Dunsley Neutraliser], although thermal stores can also be used.<br />
<br />
==== Renewable sources ====<br />
<br />
'''Solar thermal panels''' are usually used to provide [[Domestic Hot Water]] (If considering this technology one might also investigate solar warm air systems which may give better energy returns for a given cost: see [[Solar Thermal]].)<br />
<br />
'''Ground-source heat pumps''' provide energy at lower temperatures than are required for DHW and are generally used in space heating systems, often with under-floor heating which can make better use of the lower temperatures generated.<br />
<br />
Both systems, as well as [[Drain Heat Exchanger|waste water heat recovery]], can be used with thermal stores, combining their output with other systems including conventional boilers and/or electric backup heaters to provide space heating, via UFH and radiators, and DHW.<br />
<br />
''' Air-source Heat Pumps ''' - similar benefits as ground-source heat pumps and easier to install; however in locating these units, the potential noise of the fan must be taken into account as some people are very sensitive to such noise, especially at night.<br />
<br />
== Heat Emitters ==<br />
'''''Emitters''' are means of heating spaces: radiators, under-floor heating etc.''<br />
<br />
=== Radiators ===<br />
''"Radiators" actually emit heat mostly via convection rather than radiation: they heat the air which heats the fabric of the room and its occupants.''<br />
<br />
They come in a number of types -- standard panel radiators, Low Surface Temperature (LST), "designer" radiators and towel warmers -- and shapes, sizes and colours/finishes. Radiators must be chosen and located so as to provide sufficient output to heat the spaces they are installed into.<br />
<br />
There is more detail in the article:<br />
* [[Central Heating Radiators]]<br />
<br />
=== Fan-assisted heaters ===<br />
''These types use forced convection, compared to natural convection employed by radiators.''<br />
<br />
Sometimes known as kickspace heaters, these have a fan to distribute air warmed by a water-to-air heat exchanger (typically tubes with fins attached) which transfer heat from the central heating primary water.<br />
<br />
* particularly suitable for small rooms with limited wall space for rads (e.g. kitchen) or too-high heat-loss/floor-area ratio for UFH (e.g. bathroom)<br />
* fast warm-up<br />
* less localised heating effect than radiators; can be effective at heating larger areas<br />
* may feel uncomfortably cold when shut off by thermostat (like electric fan heaters)<br />
* may be too noisy for domestic use in lounges and bedrooms<br />
<br />
=== Underfloor ===<br />
<br />
''This gives radiant heat which warms occupants and fabric directly rather than warming the air.''<br />
<br />
* Requires less total heat output (figures of around 20% are quoted) for a given comfort level compared to radiator-based systems.<br />
* Tends to give warmer feet and cooler heads giving a more comfortable, less stuffy feeling.<br />
* Good for heating large spaces where it would be hard to install sufficient radiators, and spaces with high ceilings e.g. halls where the output of radiators would be lost to the higher parts of the room.<br />
* Limited heat output due to limitation on maximum comfortable floor temperatures which may be insufficient for small rooms with large heat requirements & large losses e.g. bathrooms (although the warmer floors, in conjunction with extra heating from radiators or kick-space heaters, can make for a more comfortable room than one with a cold floor).<br />
* Heat output dependent on floor coverings which need to be chosen to work with the UFH system.<br />
* Slower to heat & cool than radiator based systems, so need better control systems.<br />
* Slow thermal response leads to lower overall efficiency for spaces occupied for relatively short periods, due to the heat lost during the longer warm-up and cool-down periods.<br />
* Hydronic (hot-water) systems generally require lower water temperatures than radiator systems leading to extra complexity and expense (extra pump & thermostatic mixing valve) to run in mixed system with radiators.<br />
* The lower water temperatures required by pure UFH systems enable condensing boilers, solar collectors and heat pumps to operate more efficiently than with radiator-based systems.<br />
* Generally expensive & disruptive to retro-fit to existing building due to need to remove & relay floors (or possibly ceilings below for upper-floor installations).<br />
* Electric UFH is cheaper to install but has higher running costs: popular choice for small bath or shower rooms.<br />
More on [[Underfloor Heating]]<br />
<br />
=== Other radiant ===<br />
Walls can also be used for radiant heating. Usually this is acheived by embedding heating pipework into a solid wall surface. A discussion of the possibility of heating via stud walls can be found [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/3fe720e4cfce3a6d/c2183341d4849b0e here].<br />
<br />
Heating ceilings has the obvious disadvantage of unwanted heat loss upwards; even so one (singularly ineffective) installation is known to [[User:John Stumbles|one of the authors]].<br />
<br />
== Filling arrangements: sealed or vented ==<br />
<br />
The traditional arrangement for maintaining a body of water in the system comprises a '''feed and expansion''' (aka '''header''') tank above the highest point of the system. The tank is kept topped up by a float valve similar to that in a main cold water storage tank or WC cistern.<br />
<br />
Modern systems are usually '''sealed''' with water introduced to the system by a temporary filling hose (or special key-operated device built-in to the boiler). More info can be found in [http://www.makewrite.demon.co.uk/SealedCH.html Ed Sirett's Sealed System FAQ].<br />
<br />
For a completely new system a sealed arrangement is generally preferred, unless it is wished to use a directly heated [[Thermal Store]]. Where an old and poorly-constructed existing system is converted to sealed operation there is the possibility of minor leaks from old radiator valves and poorly-made compression joints leading to relatively rapid loss of pressure and the need to top up the system frequently. For this reason if there is no compelling requirement to convert the system it may be better left alone. Conversely if an open vented system suffers from scaling up of the feed pipe, pumping over of the vent pipe into the feed and expansion tank, microbial sludge growth in the F&E tank or air air-locks when filling up it may be worth converting to sealed operation (provided the boiler is a type for which this is permitted).<br />
<br />
== Configuration: Controls and Zoning ==<br />
<br />
An important aspect of the way a heating system is designed is the way heating is divided into physical zones, and the controls used to regulate heating. These are discussed in a separate article:<br />
* '''[[Central Heating Controls and Zoning]]'''<br />
<br />
== Pipework ==<br />
=== Pipework materials ===<br />
==== Copper ====<br />
<br />
Traditional material.<br />
<br />
Available in various grades and sizes. Those found in domestic CH installations are:<br />
<br />
* Rigid ("Table X") in small-bore sizes: 28mm, 22mm, 15mm<br />
* Fully-annealed (soft) ("Table Y") in micro-bore sizes: 10mm, 8mm<br />
<br />
Features:<br />
* Material usually more expensive than plastics<br />
* Available in lengths 1m, 2m, 3m (also 6m?). 2m and 3m are most common.<br />
* More time-consuming to install<br />
* Requires more lifting of flooring when retro-fitting to existing building<br />
* Small-bore pipes must usually be run in notches in the top of joists: susceptible to damage by nailing and contrary to building regulations.<br />
* Micro-bore pipes may be threaded through holes in joists out of reach of nailing<br />
* Micro-bore pipe may be "cabled" through floor and wall spaces with less disruption in existing building<br />
* May be noisy (e.g. clicking noises) as pipes expand & contract when heating & cooling<br />
* Surface runs can be done neatly avoiding need for boxing-in in certain locations<br />
* Can be joined with solder, compression or push-fit fittings<br />
* Micro-bore may be bent by hand (with external spring) or by small machine for neater bends<br />
* Small-bore may be bent by hand with spring for 15mm (and possibly 22mm if pipe annealed or fitter very strong)<br />
* Small-bore may be bent with large hand-held machine for 15 & 22mm, larger machine on stand for 28mm<br />
<br />
==== Plastic ====<br />
<br />
Some older installations using small-bore (15-28mm) pipework in PVC and ABS may be found but these materials are no longer used for CH pipework.<br />
<br />
Moderm materials (used for last 2 decades or so in UK) are<br />
* PB (Polybutylene)<br />
* PEX (Polyethylene cross-linked)<br />
<br />
Sizes available are:<br />
* 28mm<br />
* 22mm<br />
* 15mm<br />
* 10mm<br />
<br />
Features:<br />
* Pipework usually cheaper than copper<br />
* Pipe available in long rolls e.g. 25m, 50m and 100m<br />
* Easier & quicker to install than rigid pipe<br />
* Pipe may be "cabled" with minimum lifting of flooring in existing building<br />
* Pipes may be run through holes in joists out of reach of nailing<br />
* Pipes expand and sag when hot requiring boxing-in if run on surface<br />
* Can be joined with compression and push-fit fittings.<br />
* Long runs possible with bends in pipework and fewer fittings<br />
<br />
===== Barrier and non-barrier =====<br />
Conventional Wisdom is that only barrier pipe should be used for CH systems as the metallic barrier layer prevents oxygen diffusing through the plastic walls of the pipe into the primary water and causing corrosion in ferrous and possibly other metallic parts of the system - boilers, radiators etc. However [http://www.hep2o.co.uk/ Hepworth Plumbing Products] have stated <br />
in the uk-d-i-y newsgroup that:<br />
<blockquote><br />
If Hep2O Standard pipe has been installed in accordance with our<br />
instructions in a central heating system and one of the recommended<br />
inhibitors used there is no technical reason why it should not continue to<br />
give good service for many decades. [[http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/70540dffa9cf9f4b/34103c153f976739?rnum=1&q=If+Hep2O+Standard+pipe+has+been+installed+in+accordance+with+our&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2F70540dffa9cf9f4b%2Fe2db7ffcad95adb1%3Flnk%3Dst%26q%3DIf+Hep2O+Standard+pipe+has+been+installed+in+accordance+with+our%26rnum%3D1%26#doc_e2db7ffcad95adb1]]<br />
<br />
</blockquote><br />
and<br />
<blockquote><br />
It is now considered by British Gas that central heating systems that<br />
include plastics pipe manufactured to the appropriate British Standard<br />
(such as Hep2O) do not represent a potential corrosion problem from<br />
oxygen ingress where the system water includes an adequate strength of<br />
inhibitor. This applies equally to Barrier and Non-Barrier pipes. [[http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/ff1a4f63c1facf9e/4254068524cd8c4c?rnum=1&q=hepworth+barrier+pipe&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fff1a4f63c1facf9e%2Ff343d48ec0be74b2%3Flnk%3Dst%26q%3Dhepworth+barrier+pipe%26rnum%3D2%26#doc_f343d48ec0be74b2]]<br />
<br />
</blockquote><br />
<br />
However in real life not all central heating systems have effective corrosion inhibition at all times, so barrier pipe is still the preferred option.<br />
<br />
==== Tails ====<br />
<br />
Even in a system using plastic pipe for the main pipe runs the boiler manufacturer usually requires the first 600mm or 1m of pipework connected to the boiler to be in copper.<br />
<br />
Also many installers and/or clients prefer copper tails to radiators rather than plastic. For "designer" radiators or towel radiators in bathrooms chromed radiator tails are often preferred. Since chrome is very hard it is necessary to remove the chrome from the part of the tail pipe being connected into a push-fit fitting since the grab ring of the fitting may not bite securely into the chrome and the fitting may become detatched. It is also necessary to remove the chrome when connecting into a solder fitting since solder may not adhere properly to chrome. If using a compression fitting a brass olive is preferable to a copper one since the olive has to slightly compress the pipework to secure the fitting and the chrome may be too hard for a soft copper olive to acheive the necessary pressure.<br />
<br />
=== pipework layout ===<br />
==== pipe sizes v. heat-carrying capacities + noise ====<br />
<br />
==== Single pipe loop ====<br />
<br />
Obsolete - not used for current designs but found in some old installations.<br />
<br />
Single pipe means that radiators are plumbed in series. The problem is that as water passes through each radiator, it loses heat, so radiators at the far end of the chain have to be oversized, and run at reduced temps.<br />
<br />
Where necessary to extend (add extra rads) can either add new rad into existing loop (allowing extra size for rad if at cool end of loop) or, especially if several new rads to be added, divide system and add a seperate 2-pipe loop - perhaps as a seperate zone if it makes sense.<br />
<br />
Single pipe systems may underperform, as heating expectations are higher now than they were when these old systems were installed. Replumbing the radiators in parallel is a logical option, but there is a simpler and cheaper way to improve total heat output to some extent, and that is to increase pumping rate. The faster the pumping, the less temp loss occurs along the chain. A more powerful or 2nd pump can thus be a low cost way to increase system output.<br />
<br />
==== Tree: trunk + branch ====<br />
A good pipework arrangement has 'trunk' pipes from the boiler in 22mm (or 28mm depending on the output of the boiler and the manufacturer's instructions) with branches in 15mm (or microbore: 10mm or 8mm) to individual radiators. Pipe sizes can be stepped down from trunks through branches e.g. <br />
<br />
[[Image:Trunk-branch.gif]]<br />
<br />
==== Microbore ====<br />
<br />
The topology of a microbore installation is usually a tree with trunks of 22mm and branches of 10mm and/or 8mm pipework, and is inherently well-balanced.<br />
<br />
The fully-annealed ("Table Y") copper pipe (or flexible plastic pipe) used for the microbore sections can be bent and threaded through stud walls and joists unlike rigid copper in small-bore sizes.<br />
<br />
Some clients may prefer to have 15mm tails to radiators (joined to microbore under the floor or in the wall) for the sake of appearance.<br />
<br />
There is an article on [[Fitting_TRVs_to_Microbore|retro-fitting 15mm radiator valves to microbore]].<br />
<br />
Limited power throughput (2.5kW-ish)<br />
<br />
Narrow bore is more vulnerable to sludge.<br />
<br />
==== Dual loop ====<br />
inherently balanced but rarely practicable<br />
<br />
==== Random ====<br />
An arrangement with radiators connected with widely varying lengths of narrow-bore pipework is bad for balancing but sometimes necessary especially when extending an existing system where access under floors etc is limited.<br />
<br />
== Installation ==<br />
=== Routing ===<br />
The choice of routes for the pipework may have to incorporate a number of criteria. These may be aesthetic, cost or performance based. For instance, the performance considerations will urge you avoid routing through unheated spaces or a zone differing from the one to be heated. The cold space below a suspended ground floor is not a natural performance choice and requires effective insulation but is an overwhelmingly good choice from the cost and aesthetic aspects.<br />
<br />
Typically there are general approaches depending on the structure of the floors.<br />
* All floor(s) suspended: Main pipes run vertically between floor(s) in one place (often a corner near the boiler). Plastic pipe is a great choice as it can be cabled through joists and readily installed in runs between joists; it is also out of sight, has fewer joints and lower heat losses. Copper/chrome tails emerge through floor to supply radiator from below.<br />
* Ground floor is solid other floor(s) are suspended: The upper floors or even the loft space (for a bungalow) are used as above and also to supply the radiators in rooms below. Groups of one to three radiators (or perhaps more) are supplied from above by a pair of pipes. Each group will need a drain off point. Pipes drops are on show but can be hidden in a duct but this can make a feature out of a necessity, there will still be runs under the radiator.<br />
* All solid floors and ceiling: Copper pipes are run round at skirting board height from room to room, going through internal walls as needed. This usually leads to a inferior layout topology so needing extra care to balance the system. The entrance door is often an obstacle; it can be unsightly to go over and across and down, and that leads to the needs for air bleed points, ideally at the top of each down flowing pipe, this is a further draw back. It is often best to bite the bullet and dig the concrete up to cross under the doorway and accept that such sites have difficulties. <br />
* New build: Apart from the possibility of underfloor heating there is also the oportunity to install microbore plastic behind dry lining boards.<br />
<br />
* installation in solid floor<br />
<br />
==== Joist Notching ====<br />
Building regs impose restriction on the places and sizes for notches and holes in joists. <br />
Notches must be no more than 12.5% of joist depth installed between 10% and 25% along the spans length. <br />
The best way to cross joists is through holes bored in the middle of joists. Microbore can be cabled through, about 4 or 5 joists seems to be the maximum number that can be crossed by any single length. Flexible plastic pipe is a very welcome material in these cases, even then a good right angled joist boring drill or cordless equivalent is a must for this part of the job. Rigid pipework has to be installed in notches, which should be placed in the middle of the floor board. <br />
==== Drain-off points ====<br />
It is certainly good practice, if not manadatory, to install drain off points on the lowest points of the pipework.<br />
Ideally the best place is outside over a gully. Some radiator valves include a built in drain tap. There are two types of fittings on is known as heavy and light pattern. The heavy type have a seal around the spindle they are a little less messy when in use. There is no reason why you could not use ball-o-fix service isolators although this does not seem to be common practice. <br />
<br />
* plastic v. copper or chromed pipetails<br />
** play in tails<br />
* pressure testing<br />
* flushing<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Central_heating_design&diff=18603Central heating design2014-05-03T10:45:43Z<p>John Stumbles: /* Whole house/boiler sizing */ removed dead links to IDHE, & EST calculator</p>
<hr />
<div>This article is about [[Central heating]] systems using hot water as a heat-carrying medium. <br />
(Warm-air systems are sometimes found in the UK but their design and installation is not covered here. There is a discussion on updating existing warm-air systems [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/cd973db3a3604624? here])<br />
<br />
The article is intended as a guide to:<br />
* choosing a design for, and installing a new central heating system<br />
* understanding how an existing system is designed, for the purposes of maintaining and fault-finding<br />
<br />
There are separate articles about:<br />
* [[Central heating operation]] for help maintaining a working CH system<br />
* [[Central Heating Repair]] for diagnosing and fixing a faulty system.<br />
<br />
'''''Parts of this article are in skeleton form with main points listed but needing to be expanded'''''<br />
<br />
== Heat requirements ==<br />
In order to get a heating system which works effectively and economically it is important to calculate how much heating power will be required, into the building as a whole (in order to calculate the required size for the boiler or other heat source) and into each room (to calculate sizes of radiators or other heat emitters).<br />
<br />
=== Whole house/boiler sizing ===<br />
For boiler sizing there is a relatively simple yet sufficiently accurate calculation known as the whole-house boiler sizing method. The method is described in the<br />
* [http://www.est.org.uk/uploads/documents/housingbuildings/ce54.pdf Energy Saving Trust worksheet] (PDF)<br />
A spreadsheet implementing the calculator is available at:<br />
* [http://yaph.co.uk/heating/boiler_sizing.xls YAPH]<br />
The spreadsheet allows easy what-if calculations showing the effect of, say, cavity wall insulation on the house heating requirements.<br />
<br />
=== Heatloss/radiator sizing ===<br />
For calculating the heat requirements of rooms an elemental approach is taken.<br />
# The area of walls, windows, doors, floor and ceilings is calculated<br />
# U-values for the materials of these elements are found from tables<br />
# Temperature differences across the elements are multiplied by the above figures to calculate total ''fabric'' loss<br />
# The volume of the room is calculated<br />
# The number of air-changes per hour expected for the room is found from a table<br />
# The above two figures are multiplied together with a factor for the heat capacity of air to calculate total ''ventilation'' loss<br />
# The fabric and ventilation losses are added to calculate the total heat requirement of the room, and therefore the size of radiator or other heat-emitter(s) required.<br />
<br />
A (Microsoft Windows) computer program implementing this method is the<br />
* [http://www.quinn-radiators.co.uk/downloads_heatloss.php Barlo heatloss calculator]<br />
<br />
''* Discuss + links to energy conservation articles''<br />
<br />
== Heat Sources ==<br />
<br />
=== Fuels ===<br />
<br />
The most popular fuels for central heating systems are (in order of increasing expense):<br />
# '''Natural Gas'''<br />
# '''Oil'''<br />
# '''LPG''' (Liquefied Petroleum Gas). '''Propane''' and '''Butane''' are LPGs but for heating propane is mostly used. It is often known generically as "Calor" gas (in the same way that vacuum cleaners are known as "Hoovers").<br />
# '''Electricity''' can be used for central heating systems but where it is used for heating it is generally found used with storage heaters using off-peak rate electricity. Where no other fuel is available a system using a [[heat bank]] heated by off-peak electricity with [[Underfloor Heating]] or radiators is likely to be more economical to run than one using storage heaters or any sort of peak-rate heaters. An example of such a system is the "[http://www.gasapplianceguide.co.uk/gledhill_electramate.htm Electramate]" made by [http://www.gledhill.net/ Gledhill]. This is a ready-made package, but similar systems can be designed using other manufacturers' components.<br />
<br />
* '''solid fuel'''s - coal, anthracite etc, and wood or woodchips - are sometimes used to contribute to space and/or water heating. Nowadays they are not usually used as main fuels since most domestic appliances for using them cannot be automatically fed and regulated.<br />
<br />
'''Renewable''' sources such as:<br />
* '''solar thermal'''<br />
* '''geothermal'''<br />
are also increasingly found contributing to heating systems rather than providing sole energy supply.<br />
<br />
=== Appliances ===<br />
<br />
==== Boilers ====<br />
The most common appliances for supplying heat are '''boilers''' using natural gas, oil or LPG to heat "'''primary'''" water. Primary water is water intended for heating rooms via radiators etc or heating "'''secondary'''" water for washing etc (see '''[[Domestic Hot Water|DHW]]'''). Some boilers - known as '''combi''' boilers - heat DHW directly.<br />
<br />
''For further discussion of types of boiler, combi/conventional choice etc see:<br />
*[[Boiler]]s<br />
*[http://www.makewrite.demon.co.uk/BoilerChoice.html Ed's Boiler Choice FAQ]''<br />
<br />
Electric boilers perform the same function as non-combi boilers using electricity. They can be expected to have very high running costs compared to natural gas, oil or LPG boilers.<br />
<br />
==== Ranges ====<br />
'''Ranges''' e.g. '''Aga'''s and '''Rayburn'''s usually heat DHW as a by-product of their cooking functions. They may use natural gas, oil, LPG or solid fuels.<br />
<br />
'''Combined range/boilers''' appear outwardly almost identical to ranges but contain a separate central heating boiler sharing the flue of the cooking range. They may use natural gas, oil or LPG. They are generally non-condensing appliances and therefore less efficient than current central heating boilers (one exception being the [http://www.rayburn-web.co.uk/57_266.htm Rayburn 480 CD] which has a condensing boiler section: this gas-only appliance is only available with a balanced flue).<br />
<br />
==== CHP ====<br />
'''Combined Heat and Power (CHP)''' generators (e.g. '''[http://www.microgen.com/ Microgen]''', '''[http://www.whispergen.com/ Whispergen]''') generate electrical power whilst heating primary water.<br />
<br />
They generate electricity with much lower efficiency than fossil fuel generated electricity supplied by conventional central power stations, but they only generate when heat is wanted, which means all the heat and electricity output is used. This makes the overall picture more efficient than a central power station, where over half the input energy is wasted as heat. So overall the method works out more energy efficient.<br />
<br />
CHP requires non-trivial arrangements for connection into the domestic electricity supply, and financial and administrative arrangements to sell surplus electricity back to the supplier.<br />
<br />
CHP is a well established technology for large facilities, but domestic CHP generators are not readily available in the UK at present (Feb 2007), partly due to concerns about some aspects of the systems and lack of a solid proven track record of domestic CHP or the products on offer.<br />
<br />
==== Solid-fuel back-boilers ====<br />
Traditional coal fires or more modern wood-burning stoves with back boilers can contribute to domestic space or water heating. Their heating output is sometimes combined with that of a main heating boiler by means of a [http://www.dunsleyheat.co.uk/linkupsys.htm Dunsley Neutraliser], although thermal stores can also be used.<br />
<br />
==== Renewable sources ====<br />
<br />
'''Solar thermal panels''' are usually used to provide [[Domestic Hot Water]] (If considering this technology one might also investigate solar warm air systems which may give better energy returns for a given cost: see [[Solar Thermal]].)<br />
<br />
'''Ground-source heat pumps''' provide energy at lower temperatures than are required for DHW and are generally used in space heating systems, often with under-floor heating which can make better use of the lower temperatures generated.<br />
<br />
Both systems, as well as [[Drain Heat Exchanger|waste water heat recovery]], can be used with thermal stores, combining their output with other systems including conventional boilers and/or electric backup heaters to provide space heating, via UFH and radiators, and DHW.<br />
<br />
''' Air-source Heat Pumps ''' - similar benefits as ground-source heat pumps and easier to install; however in locating these units, the potential noise of the fan must be taken into account as some people are very sensitive to such noise, especially at night.<br />
<br />
== Heat Emitters ==<br />
'''''Emitters''' are means of heating spaces: radiators, under-floor heating etc.''<br />
<br />
=== Radiators ===<br />
''"Radiators" actually emit heat mostly via convection rather than radiation: they heat the air which heats the fabric of the room and its occupants.''<br />
<br />
They come in a number of types -- standard panel radiators, Low Surface Temperature (LST), "designer" radiators and towel warmers -- and shapes, sizes and colours/finishes. Radiators must be chosen and located so as to provide sufficient output to heat the spaces they are installed into.<br />
<br />
There is more detail in the article:<br />
* [[Central Heating Radiators]]<br />
<br />
=== Fan-assisted heaters ===<br />
''These types use forced convection, compared to natural convection employed by radiators.''<br />
<br />
Sometimes known as kickspace heaters, these have a fan to distribute air warmed by a water-to-air heat exchanger (typically tubes with fins attached) which transfer heat from the central heating primary water.<br />
<br />
* particularly suitable for small rooms with limited wall space for rads (e.g. kitchen) or too-high heat-loss/floor-area ratio for UFH (e.g. bathroom)<br />
* fast warm-up<br />
* less localised heating effect than radiators; can be effective at heating larger areas<br />
* may feel uncomfortably cold when shut off by thermostat (like electric fan heaters)<br />
* may be too noisy for domestic use in lounges and bedrooms<br />
<br />
=== Underfloor ===<br />
<br />
''This gives radiant heat which warms occupants and fabric directly rather than warming the air.''<br />
<br />
* Requires less total heat output (figures of around 20% are quoted) for a given comfort level compared to radiator-based systems.<br />
* Tends to give warmer feet and cooler heads giving a more comfortable, less stuffy feeling.<br />
* Good for heating large spaces where it would be hard to install sufficient radiators, and spaces with high ceilings e.g. halls where the output of radiators would be lost to the higher parts of the room.<br />
* Limited heat output due to limitation on maximum comfortable floor temperatures which may be insufficient for small rooms with large heat requirements & large losses e.g. bathrooms (although the warmer floors, in conjunction with extra heating from radiators or kick-space heaters, can make for a more comfortable room than one with a cold floor).<br />
* Heat output dependent on floor coverings which need to be chosen to work with the UFH system.<br />
* Slower to heat & cool than radiator based systems, so need better control systems.<br />
* Slow thermal response leads to lower overall efficiency for spaces occupied for relatively short periods, due to the heat lost during the longer warm-up and cool-down periods.<br />
* Hydronic (hot-water) systems generally require lower water temperatures than radiator systems leading to extra complexity and expense (extra pump & thermostatic mixing valve) to run in mixed system with radiators.<br />
* The lower water temperatures required by pure UFH systems enable condensing boilers, solar collectors and heat pumps to operate more efficiently than with radiator-based systems.<br />
* Generally expensive & disruptive to retro-fit to existing building due to need to remove & relay floors (or possibly ceilings below for upper-floor installations).<br />
* Electric UFH is cheaper to install but has higher running costs: popular choice for small bath or shower rooms.<br />
More on [[Underfloor Heating]]<br />
<br />
=== Other radiant ===<br />
Walls can also be used for radiant heating. Usually this is acheived by embedding heating pipework into a solid wall surface. A discussion of the possibility of heating via stud walls can be found [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/3fe720e4cfce3a6d/c2183341d4849b0e here].<br />
<br />
Heating ceilings has the obvious disadvantage of unwanted heat loss upwards; even so one (singularly ineffective) installation is known to [[User:John Stumbles|one of the authors]].<br />
<br />
== Filling arrangements: sealed or vented ==<br />
<br />
The traditional arrangement for maintaining a body of water in the system comprises a '''feed and expansion''' (aka '''header''') tank above the highest point of the system. The tank is kept topped up by a float valve similar to that in a main cold water storage tank or WC cistern.<br />
<br />
Modern systems are usually '''sealed''' with water introduced to the system by a temporary filling hose (or special key-operated device built-in to the boiler). More info can be found in [http://www.makewrite.demon.co.uk/SealedCH.html Ed Sirett's Sealed System FAQ].<br />
<br />
For a completely new system a sealed arrangement is generally preferred, unless it is wished to use a directly heated [[Thermal Store]]. Where an old and poorly-constructed existing system is converted to sealed operation there is the possibility of minor leaks from old radiator valves and poorly-made compression joints leading to relatively rapid loss of pressure and the need to top up the system frequently. For this reason if there is no compelling requirement to convert the system it may be better left alone. Conversely if an open vented system suffers from scaling up of the feed pipe, pumping over of the vent pipe into the feed and expansion tank, microbial sludge growth in the F&E tank or air air-locks when filling up it may be worth converting to sealed operation (provided the boiler is a type for which this is permitted).<br />
<br />
== Configuration: Controls and Zoning ==<br />
<br />
An important aspect of the way a heating system is designed is the way heating is divided into physical zones, and the controls used to regulate heating. These are discussed in a separate article:<br />
* '''[[Central Heating Controls and Zoning]]'''<br />
<br />
== Pipework ==<br />
=== Pipework materials ===<br />
==== Copper ====<br />
<br />
Traditional material.<br />
<br />
Available in various grades and sizes. Those found in domestic CH installations are:<br />
<br />
* Rigid ("Table X") in small-bore sizes: 28mm, 22mm, 15mm<br />
* Fully-annealed (soft) ("Table Y") in micro-bore sizes: 10mm, 8mm<br />
<br />
Features:<br />
* Material usually more expensive than plastics<br />
* Available in lengths 1m, 2m, 3m (also 6m?). 2m and 3m are most common.<br />
* More time-consuming to install<br />
* Requires more lifting of flooring when retro-fitting to existing building<br />
* Small-bore pipes must usually be run in notches in the top of joists: susceptible to damage by nailing and contrary to building regulations.<br />
* Micro-bore pipes may be threaded through holes in joists out of reach of nailing<br />
* Micro-bore pipe may be "cabled" through floor and wall spaces with less disruption in existing building<br />
* May be noisy (e.g. clicking noises) as pipes expand & contract when heating & cooling<br />
* Surface runs can be done neatly avoiding need for boxing-in in certain locations<br />
* Can be joined with solder, compression or push-fit fittings<br />
* Micro-bore may be bent by hand (with external spring) or by small machine for neater bends<br />
* Small-bore may be bent by hand with spring for 15mm (and possibly 22mm if pipe annealed or fitter very strong)<br />
* Small-bore may be bent with large hand-held machine for 15 & 22mm, larger machine on stand for 28mm<br />
<br />
==== Plastic ====<br />
<br />
Some older installations using small-bore (15-28mm) pipework in PVC and ABS may be found but these materials are no longer used for CH pipework.<br />
<br />
Moderm materials (used for last 2 decades or so in UK) are<br />
* PB (Polybutylene)<br />
* PEX (Polyethylene cross-linked)<br />
<br />
Sizes available are:<br />
* 28mm<br />
* 22mm<br />
* 15mm<br />
* 10mm<br />
<br />
Features:<br />
* Pipework usually cheaper than copper<br />
* Pipe available in long rolls e.g. 25m, 50m and 100m<br />
* Easier & quicker to install than rigid pipe<br />
* Pipe may be "cabled" with minimum lifting of flooring in existing building<br />
* Pipes may be run through holes in joists out of reach of nailing<br />
* Pipes expand and sag when hot requiring boxing-in if run on surface<br />
* Can be joined with compression and push-fit fittings.<br />
* Long runs possible with bends in pipework and fewer fittings<br />
<br />
===== Barrier and non-barrier =====<br />
Conventional Wisdom is that only barrier pipe should be used for CH systems as the metallic barrier layer prevents oxygen diffusing through the plastic walls of the pipe into the primary water and causing corrosion in ferrous and possibly other metallic parts of the system - boilers, radiators etc. However [http://www.hep2o.co.uk/ Hepworth Plumbing Products] have stated <br />
in the uk-d-i-y newsgroup that:<br />
<blockquote><br />
If Hep2O Standard pipe has been installed in accordance with our<br />
instructions in a central heating system and one of the recommended<br />
inhibitors used there is no technical reason why it should not continue to<br />
give good service for many decades. [[http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/70540dffa9cf9f4b/34103c153f976739?rnum=1&q=If+Hep2O+Standard+pipe+has+been+installed+in+accordance+with+our&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2F70540dffa9cf9f4b%2Fe2db7ffcad95adb1%3Flnk%3Dst%26q%3DIf+Hep2O+Standard+pipe+has+been+installed+in+accordance+with+our%26rnum%3D1%26#doc_e2db7ffcad95adb1]]<br />
<br />
</blockquote><br />
and<br />
<blockquote><br />
It is now considered by British Gas that central heating systems that<br />
include plastics pipe manufactured to the appropriate British Standard<br />
(such as Hep2O) do not represent a potential corrosion problem from<br />
oxygen ingress where the system water includes an adequate strength of<br />
inhibitor. This applies equally to Barrier and Non-Barrier pipes. [[http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/ff1a4f63c1facf9e/4254068524cd8c4c?rnum=1&q=hepworth+barrier+pipe&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fff1a4f63c1facf9e%2Ff343d48ec0be74b2%3Flnk%3Dst%26q%3Dhepworth+barrier+pipe%26rnum%3D2%26#doc_f343d48ec0be74b2]]<br />
<br />
</blockquote><br />
<br />
However in real life not all central heating systems have effective corrosion inhibition at all times, so barrier pipe is still the preferred option.<br />
<br />
==== Tails ====<br />
<br />
Even in a system using plastic pipe for the main pipe runs the boiler manufacturer usually requires the first 600mm or 1m of pipework connected to the boiler to be in copper.<br />
<br />
Also many installers and/or clients prefer copper tails to radiators rather than plastic. For "designer" radiators or towel radiators in bathrooms chromed radiator tails are often preferred. Since chrome is very hard it is necessary to remove the chrome from the part of the tail pipe being connected into a push-fit fitting since the grab ring of the fitting may not bite securely into the chrome and the fitting may become detatched. It is also necessary to remove the chrome when connecting into a solder fitting since solder may not adhere properly to chrome. If using a compression fitting a brass olive is preferable to a copper one since the olive has to slightly compress the pipework to secure the fitting and the chrome may be too hard for a soft copper olive to acheive the necessary pressure.<br />
<br />
=== pipework layout ===<br />
==== pipe sizes v. heat-carrying capacities + noise ====<br />
<br />
==== Single pipe loop ====<br />
<br />
This arrangement is not used for current designs but may be found in older installations (e.g. 1960s and early 1970s), and it may be required to extend such systems.<br />
<br />
The general topology is a single pipe run in a loop from the boiler's flow back to its return (via a circulating pump) with the radiators connected into the pipe loop via plumbing Tees (sometimes swept Tees). This arrangement is usually immediately obvious as the main loop pipe runs underneath the radiator. Although one might expect all the heating water to take the more direct route through the pipe, enough rises into the radiator, travels along it (losing heat as it goes) and sinks back to the main pipe at the other end to keep the radiator hot and emitting heat.<br />
<br />
This arrangement means that radiators further from the boiler's flow / closer to the return end of the loop run at slightly lower temperatures than those at the flow end so should be oversized to give their desired output at their reduced temperatures. Also the circulating pump for a single pipe loop is doing a certain amount of work just circulating water through the pipes so less of its effort is available for circulation through the radiators.<br />
<br />
Where it is necessary to add, say, one or two extra radiators to such a system they can be added into the existing loop (allowing for over-sizing if they are at the cooler return end of loop). However if many extra radiators are to be added it may be better to divide the system into two (or more) separate loops if possible (or to add a separate normal 2-pipe loop, perhaps as a separate zone).<br />
<br />
==== Tree: trunk + branch ====<br />
A good pipework arrangement has 'trunk' pipes from the boiler in 22mm (or 28mm depending on the output of the boiler and the manufacturer's instructions) with branches in 15mm (or microbore: 10mm or 8mm) to individual radiators. Pipe sizes can be stepped down from trunks through branches e.g. <br />
<br />
[[Image:Trunk-branch.gif]]<br />
<br />
==== Microbore ====<br />
<br />
The topology of a microbore installation is usually a tree with trunks of 22mm and branches of 10mm and/or 8mm pipework, and is inherently well-balanced.<br />
<br />
The fully-annealed ("Table Y") copper pipe (or flexible plastic pipe) used for the microbore sections can be bent and threaded through stud walls and joists unlike rigid copper in small-bore sizes.<br />
<br />
Some clients may prefer to have 15mm tails to radiators (joined to microbore under the floor or in the wall) for the sake of appearance.<br />
<br />
There is an article on [[Fitting_TRVs_to_Microbore|retro-fitting 15mm radiator valves to microbore]].<br />
<br />
Limited power throughput (2.5kW-ish)<br />
<br />
Narrow bore is more vulnerable to sludge.<br />
<br />
==== Dual loop ====<br />
inherently balanced but rarely practicable<br />
<br />
==== Random ====<br />
An arrangement with radiators connected with widely varying lengths of narrow-bore pipework is bad for balancing but sometimes necessary especially when extending an existing system where access under floors etc is limited.<br />
<br />
== Installation ==<br />
=== Routing ===<br />
The choice of routes for the pipework may have to incorporate a number of criteria. These may be aesthetic, cost or performance based. For instance, the performance considerations will urge you avoid routing through unheated spaces or a zone differing from the one to be heated. The cold space below a suspended ground floor is not a natural performance choice and requires effective insulation but is an overwhelmingly good choice from the cost and aesthetic aspects.<br />
<br />
Typically there are general approaches depending on the structure of the floors.<br />
* All floor(s) suspended: Main pipes run vertically between floor(s) in one place (often a corner near the boiler). Plastic pipe is a great choice as it can be cabled through joists and readily installed in runs between joists; it is also out of sight, has fewer joints and lower heat losses. Copper/chrome tails emerge through floor to supply radiator from below.<br />
* Ground floor is solid other floor(s) are suspended: The upper floors or even the loft space (for a bungalow) are used as above and also to supply the radiators in rooms below. Groups of one to three radiators (or perhaps more) are supplied from above by a pair of pipes. Each group will need a drain off point. Pipes drops are on show but can be hidden in a duct but this can make a feature out of a necessity, there will still be runs under the radiator.<br />
* All solid floors and ceiling: Copper pipes are run round at skirting board height from room to room, going through internal walls as needed. This usually leads to a inferior layout topology so needing extra care to balance the system. The entrance door is often an obstacle; it can be unsightly to go over and across and down, and that leads to the needs for air bleed points, ideally at the top of each down flowing pipe, this is a further draw back. It is often best to bite the bullet and dig the concrete up to cross under the doorway and accept that such sites have difficulties. <br />
* New build: Apart from the possibility of underfloor heating there is also the oportunity to install microbore plastic behind dry lining boards.<br />
<br />
* installation in solid floor<br />
<br />
==== Joist Notching ====<br />
Building regs impose restriction on the places and sizes for notches and holes in joists. <br />
Notches must be no more than 12.5% of joist depth installed between 10% and 25% along the spans length. <br />
The best way to cross joists is through holes bored in the middle of joists. Microbore can be cabled through, about 4 or 5 joists seems to be the maximum number that can be crossed by any single length. Flexible plastic pipe is a very welcome material in these cases, even then a good right angled joist boring drill or cordless equivalent is a must for this part of the job. Rigid pipework has to be installed in notches, which should be placed in the middle of the floor board. <br />
==== Drain-off points ====<br />
It is certainly good practice, if not manadatory, to install drain off points on the lowest points of the pipework.<br />
Ideally the best place is outside over a gully. Some radiator valves include a built in drain tap. There are two types of fittings on is known as heavy and light pattern. The heavy type have a seal around the spindle they are a little less messy when in use. There is no reason why you could not use ball-o-fix service isolators although this does not seem to be common practice. <br />
<br />
* plastic v. copper or chromed pipetails<br />
** play in tails<br />
* pressure testing<br />
* flushing<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Boiler_Evolution&diff=18401Boiler Evolution2013-12-10T00:55:08Z<p>John Stumbles: /* High efficiency, single heat exchanger */</p>
<hr />
<div>'''''This article is incomplete. You can help by expanding it or adding information and suggestions on the Talk ([[Talk:Boiler_Evolution|Discussion]]) page.'''''<br />
<br />
There have been huge developments in the technology used in gas boilers over the last 30 years, and modern purpose-designed high-efficiency condensing boilers have practically nothing in common with floor-standing dinosaurs (still found in many older installations). However an evolution of design can be seen through the different generations of appliance which may help to understand aspects of their designs. There are models which are 'links' between the 'stages' these stages are not hard and fast and hybrid models do exist; furthermore the same model name can span several generations of tech level.<br />
<br />
=== Non-electric ===<br />
No electrical connection to mains so non-electrically operated main gas valve/thermostat etc.<br />
<br />
Thought to be extinct in the wild: not discussed here.<br />
<br />
=== Low-efficiency open flue ===<br />
<br />
* Cast iron heat exchanger<br />
* Permanent, manually-ignited pilot light which is alight when the boiler is on standby as well as when it is running.<br />
* Thermocouple which senses pilot light and stops flow of gas if flame not detected.<br />
* Main burner which operates when mains power is applied to boiler (from system controls).<br />
* Built-in thermostat controlling boiler water temperature, via a rotary knob (often marked 0-6 with OFF position).<br />
* Open (natural draught) flue: products of combustion are drawn up the flue by convection due the lower density of hot flue gases relative to cool air.<br />
* Draught diverter: a downward-facing-fan- or cone-shaped duct in the flue allows air to be drawn up the flue along with the flue gases.<br />
* Air for combustion is taken from the room in which the boiler installed.<br />
<br />
Examples of this type of boiler (note that often the same models had both open and balanced flue variants):<br />
* Potterton Kingfisher<br />
* Baxi Bermuda back-boilers (combination units with gas fires in front, fitted into a fireplace with a flue-liner up the chimney)<br />
* Ideal Mexico.<br />
* Ideal Concord<br />
<br />
=== Low-efficiency balanced flue ===<br />
<br />
Early boilers of the type above had open (conventional) flues. Newer models had '''balanced flues''' in which flue gases exited via a large rectangular duct at the back of the boiler and air for combustion was drawn in through a concentric or parallel compartment of the duct. These types - also known as '''room sealed''' - are inherently safer than open flues since:<br />
* there is no connection between the flue and the room in which the boiler is installed<br />
* the boiler is not dependent on ventilation into the room for its combustion air: incomplete combustion can result in production of Carbon Monoxide<br />
* fluff and dust in the room doesn't get into the boiler's burners (or filters) which can block them up causing imcomplete combustion.<br />
<br />
Otherwise the technology of the boilers was similar except:<br />
* the combustion chamber is fully enclosed preventing ready exchange of gases between the combustion side and the room side. Some boilers were available in both open and balanced flue versions, though the open flue types, whilst open to the room for the purpose of drawing in combustion air, typically do not have a draught diverter in the flue.<br />
* piezo-electric spark ignition of pilot light. (Some later designs of purely open flue boilers had this too, particularly back boilers where the pilot light was hard to reach.)<br />
<br />
Examples:<br />
* Ideal Mexico<br />
* Glowworm Space Saver<br />
<br />
=== Standard efficiency, fanned-flue, automatic pilot light ===<br />
<br />
A change of building regulations obliged boiler manufacturers to improve the efficiency of their products. A typical boiler of this period has:<br />
* Cast-iron heat exchanger.<br />
* Room-sealed design.<br />
* Fan-assisted flue which allowed for much more versatile flue length and positioning.<br />
* Air pressure switch to ensure fan is running before opening the pilot valve.<br />
* Pilot light ignited automatically by electronic spark ignition.<br />
* PCB with electrics/electronics.<br />
Consequently the boiler's electronics took over from the pilot light and thermocouple the job of sensing that the burners were alight. <br />
<br />
Examples:<br />
* Potterton Profile & Netaheat Electronic<br />
* Potterton Kingfisher MFL <br />
* Baxi Solo2<br />
* Glowworm Fuel Saver and Micron<br />
<br />
=== Standard efficiency, no pilot light ===<br />
<br />
Later standard efficiency models dispensed with the vestigial pilot light inherited from low-efficiency designs and featured direct ignition of the main burner. Such model usually have a modulating gas valve which can vary the gas output under the control of the PCB electronics. Some of the manufacturers began using digital electronics.<br />
<br />
Examples:<br />
* Worcester CBi<br />
* Potterton Suprima<br />
* Baxi Combi, Combi "Eco" (short for "Economy"), Combi Maxflow (storage combi)<br />
* Most Combination boilers without a permanent pilot light that aren't High Efficiency models.<br />
<br />
=== High efficiency, secondary heat exchanger === <br />
<br />
With a move (enforced by a change of building regulations in 2005) to the higher efficiencies, available through condensing the steam present in flue gases back into water, boiler designs changed again. Some designs clearly adapted the technology of standard-efficiency boilers with the addition of a secondary heat exchanger operating on the flue gases of a cast-iron exchanger inherited from a standard-efficiency design. These have tended to be bulkier and/or more tightly-packed internally, sometimes with poor layout where the added components have obviously had to be shoe-horned into a package intended originally for fewer parts. <br />
<br />
All condensing boilers of this type have:<br />
* a condensate waste pipe<br />
* plastic flue pipe (or flue portion of concentric flue assembly) angled back to boiler from outside (in horizontal flue arrangements)<br />
<br />
Examples:<br />
* Baxi Barcelona <br />
* Biasi<br />
* Potterton Suprima HE.<br />
<br />
=== High efficiency, single heat exchanger === <br />
<br />
A typical modern condensing boiler features:<br />
* purpose-designed heat exchanger made of stainless steel, aluminium or other materials<br />
* pre-mix burner: where air and gas are mixed in the correct proportions for combustion and blown into the combustion chamber, often so the flame fires downwards<br />
* modulating burner (by varying the speed of the premix fan). <br />
* syphonic condensate trap storing and dispensing condensate waste in batches rather than a trickle<br />
* Digital electronic controls.<br />
<br />
Examples:<br />
* Alpha CD range of boilers (CDC,CDS,CDX,CDR) [http://www.alpha-innovation.co.uk/products/downloads/brochures/alpha_Full_Range_products_brochure.pdf brochure]<br />
* Baxi Combi HE plus ''(upward firing burner)'' ([http://www.baxi.co.uk/products/literature/Baxi_HE_Plus_Range.pdf brochure])<br />
* Baxi Platinum Combi HE ([http://www.baxi.co.uk/products/literature/Baxi_Platinum_Brochure.pdf brochure] [http://www.baxi.co.uk/products/literature/Baxi_Platinum_Installation_Guide.pdf manual])<br />
* Worcester Greenstar ([http://www.worcester-bosch.co.uk/installer/boilers/gas-boilers web page])<br />
* Vaillant Ecomax/Ecotec<br />
* Potterton Promax Combi/System HE plus (a.k.a. "Gold") ([http://www.potterton.co.uk/products/literature/PromaxHE_Plus_brochure.pdf brochure])<br />
* Potterton Promax HE plus Heating ''(upward firing burner)'' (brochure as above)<br />
* Ideal Isar / Icos / Istor<br />
* Keston Celsius<br />
<br />
[[Category:Plumbing]]<br />
[[Category:Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Boiler_Evolution&diff=18400Boiler Evolution2013-12-10T00:54:28Z<p>John Stumbles: /* High efficiency, single heat exchanger */</p>
<hr />
<div>'''''This article is incomplete. You can help by expanding it or adding information and suggestions on the Talk ([[Talk:Boiler_Evolution|Discussion]]) page.'''''<br />
<br />
There have been huge developments in the technology used in gas boilers over the last 30 years, and modern purpose-designed high-efficiency condensing boilers have practically nothing in common with floor-standing dinosaurs (still found in many older installations). However an evolution of design can be seen through the different generations of appliance which may help to understand aspects of their designs. There are models which are 'links' between the 'stages' these stages are not hard and fast and hybrid models do exist; furthermore the same model name can span several generations of tech level.<br />
<br />
=== Non-electric ===<br />
No electrical connection to mains so non-electrically operated main gas valve/thermostat etc.<br />
<br />
Thought to be extinct in the wild: not discussed here.<br />
<br />
=== Low-efficiency open flue ===<br />
<br />
* Cast iron heat exchanger<br />
* Permanent, manually-ignited pilot light which is alight when the boiler is on standby as well as when it is running.<br />
* Thermocouple which senses pilot light and stops flow of gas if flame not detected.<br />
* Main burner which operates when mains power is applied to boiler (from system controls).<br />
* Built-in thermostat controlling boiler water temperature, via a rotary knob (often marked 0-6 with OFF position).<br />
* Open (natural draught) flue: products of combustion are drawn up the flue by convection due the lower density of hot flue gases relative to cool air.<br />
* Draught diverter: a downward-facing-fan- or cone-shaped duct in the flue allows air to be drawn up the flue along with the flue gases.<br />
* Air for combustion is taken from the room in which the boiler installed.<br />
<br />
Examples of this type of boiler (note that often the same models had both open and balanced flue variants):<br />
* Potterton Kingfisher<br />
* Baxi Bermuda back-boilers (combination units with gas fires in front, fitted into a fireplace with a flue-liner up the chimney)<br />
* Ideal Mexico.<br />
* Ideal Concord<br />
<br />
=== Low-efficiency balanced flue ===<br />
<br />
Early boilers of the type above had open (conventional) flues. Newer models had '''balanced flues''' in which flue gases exited via a large rectangular duct at the back of the boiler and air for combustion was drawn in through a concentric or parallel compartment of the duct. These types - also known as '''room sealed''' - are inherently safer than open flues since:<br />
* there is no connection between the flue and the room in which the boiler is installed<br />
* the boiler is not dependent on ventilation into the room for its combustion air: incomplete combustion can result in production of Carbon Monoxide<br />
* fluff and dust in the room doesn't get into the boiler's burners (or filters) which can block them up causing imcomplete combustion.<br />
<br />
Otherwise the technology of the boilers was similar except:<br />
* the combustion chamber is fully enclosed preventing ready exchange of gases between the combustion side and the room side. Some boilers were available in both open and balanced flue versions, though the open flue types, whilst open to the room for the purpose of drawing in combustion air, typically do not have a draught diverter in the flue.<br />
* piezo-electric spark ignition of pilot light. (Some later designs of purely open flue boilers had this too, particularly back boilers where the pilot light was hard to reach.)<br />
<br />
Examples:<br />
* Ideal Mexico<br />
* Glowworm Space Saver<br />
<br />
=== Standard efficiency, fanned-flue, automatic pilot light ===<br />
<br />
A change of building regulations obliged boiler manufacturers to improve the efficiency of their products. A typical boiler of this period has:<br />
* Cast-iron heat exchanger.<br />
* Room-sealed design.<br />
* Fan-assisted flue which allowed for much more versatile flue length and positioning.<br />
* Air pressure switch to ensure fan is running before opening the pilot valve.<br />
* Pilot light ignited automatically by electronic spark ignition.<br />
* PCB with electrics/electronics.<br />
Consequently the boiler's electronics took over from the pilot light and thermocouple the job of sensing that the burners were alight. <br />
<br />
Examples:<br />
* Potterton Profile & Netaheat Electronic<br />
* Potterton Kingfisher MFL <br />
* Baxi Solo2<br />
* Glowworm Fuel Saver and Micron<br />
<br />
=== Standard efficiency, no pilot light ===<br />
<br />
Later standard efficiency models dispensed with the vestigial pilot light inherited from low-efficiency designs and featured direct ignition of the main burner. Such model usually have a modulating gas valve which can vary the gas output under the control of the PCB electronics. Some of the manufacturers began using digital electronics.<br />
<br />
Examples:<br />
* Worcester CBi<br />
* Potterton Suprima<br />
* Baxi Combi, Combi "Eco" (short for "Economy"), Combi Maxflow (storage combi)<br />
* Most Combination boilers without a permanent pilot light that aren't High Efficiency models.<br />
<br />
=== High efficiency, secondary heat exchanger === <br />
<br />
With a move (enforced by a change of building regulations in 2005) to the higher efficiencies, available through condensing the steam present in flue gases back into water, boiler designs changed again. Some designs clearly adapted the technology of standard-efficiency boilers with the addition of a secondary heat exchanger operating on the flue gases of a cast-iron exchanger inherited from a standard-efficiency design. These have tended to be bulkier and/or more tightly-packed internally, sometimes with poor layout where the added components have obviously had to be shoe-horned into a package intended originally for fewer parts. <br />
<br />
All condensing boilers of this type have:<br />
* a condensate waste pipe<br />
* plastic flue pipe (or flue portion of concentric flue assembly) angled back to boiler from outside (in horizontal flue arrangements)<br />
<br />
Examples:<br />
* Baxi Barcelona <br />
* Biasi<br />
* Potterton Suprima HE.<br />
<br />
=== High efficiency, single heat exchanger === <br />
<br />
A typical modern condensing boiler features:<br />
* purpose-designed heat exchanger made of stainless steel, aluminium or other materials<br />
* pre-mix burner: where air and gas are mixed in the correct proportions for combustion and blown into the combustion chamber, often so the flame fires downwards<br />
* modulating burner (by varying the speed of the premix fan). <br />
* syphonic condensate trap storing and dispensing condensate waste in batches rather than a trickle<br />
* Digital electronic controls.<br />
<br />
Examples:<br />
* Alpha CD range of boilers (CDC,CDS,CDX,CDR) [http://www.alpha-innovation.co.uk/products/downloads/brochures/alpha_Full_Range_products_brochure.pdf brochure]<br />
* Baxi Combi HE plus ''(upward firing burner)'' ([http://www.baxi.co.uk/products/literature/Baxi_HE_Plus_Range.pdf brochure])<br />
* Baxi Platinum Combi HE ([http://www.baxi.co.uk/products/literature/Baxi_Platinum_Brochure.pdf brochure] [http://www.baxi.co.uk/products/literature/Baxi_Platinum_Installation_Guide.pdf manual])<br />
* Worcester Greenstar ([http://www.worcester-bosch.co.uk/installer/boilers/gas-boilers])<br />
* Vaillant Ecomax/Ecotec<br />
* Potterton Promax Combi/System HE plus (a.k.a. "Gold") ([http://www.potterton.co.uk/products/literature/PromaxHE_Plus_brochure.pdf brochure])<br />
* Potterton Promax HE plus Heating ''(upward firing burner)'' (brochure as above)<br />
* Ideal Isar / Icos / Istor<br />
* Keston Celsius<br />
<br />
[[Category:Plumbing]]<br />
[[Category:Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Boiler_Evolution&diff=18399Boiler Evolution2013-12-10T00:52:58Z<p>John Stumbles: /* High efficiency, single heat exchanger */ typo</p>
<hr />
<div>'''''This article is incomplete. You can help by expanding it or adding information and suggestions on the Talk ([[Talk:Boiler_Evolution|Discussion]]) page.'''''<br />
<br />
There have been huge developments in the technology used in gas boilers over the last 30 years, and modern purpose-designed high-efficiency condensing boilers have practically nothing in common with floor-standing dinosaurs (still found in many older installations). However an evolution of design can be seen through the different generations of appliance which may help to understand aspects of their designs. There are models which are 'links' between the 'stages' these stages are not hard and fast and hybrid models do exist; furthermore the same model name can span several generations of tech level.<br />
<br />
=== Non-electric ===<br />
No electrical connection to mains so non-electrically operated main gas valve/thermostat etc.<br />
<br />
Thought to be extinct in the wild: not discussed here.<br />
<br />
=== Low-efficiency open flue ===<br />
<br />
* Cast iron heat exchanger<br />
* Permanent, manually-ignited pilot light which is alight when the boiler is on standby as well as when it is running.<br />
* Thermocouple which senses pilot light and stops flow of gas if flame not detected.<br />
* Main burner which operates when mains power is applied to boiler (from system controls).<br />
* Built-in thermostat controlling boiler water temperature, via a rotary knob (often marked 0-6 with OFF position).<br />
* Open (natural draught) flue: products of combustion are drawn up the flue by convection due the lower density of hot flue gases relative to cool air.<br />
* Draught diverter: a downward-facing-fan- or cone-shaped duct in the flue allows air to be drawn up the flue along with the flue gases.<br />
* Air for combustion is taken from the room in which the boiler installed.<br />
<br />
Examples of this type of boiler (note that often the same models had both open and balanced flue variants):<br />
* Potterton Kingfisher<br />
* Baxi Bermuda back-boilers (combination units with gas fires in front, fitted into a fireplace with a flue-liner up the chimney)<br />
* Ideal Mexico.<br />
* Ideal Concord<br />
<br />
=== Low-efficiency balanced flue ===<br />
<br />
Early boilers of the type above had open (conventional) flues. Newer models had '''balanced flues''' in which flue gases exited via a large rectangular duct at the back of the boiler and air for combustion was drawn in through a concentric or parallel compartment of the duct. These types - also known as '''room sealed''' - are inherently safer than open flues since:<br />
* there is no connection between the flue and the room in which the boiler is installed<br />
* the boiler is not dependent on ventilation into the room for its combustion air: incomplete combustion can result in production of Carbon Monoxide<br />
* fluff and dust in the room doesn't get into the boiler's burners (or filters) which can block them up causing imcomplete combustion.<br />
<br />
Otherwise the technology of the boilers was similar except:<br />
* the combustion chamber is fully enclosed preventing ready exchange of gases between the combustion side and the room side. Some boilers were available in both open and balanced flue versions, though the open flue types, whilst open to the room for the purpose of drawing in combustion air, typically do not have a draught diverter in the flue.<br />
* piezo-electric spark ignition of pilot light. (Some later designs of purely open flue boilers had this too, particularly back boilers where the pilot light was hard to reach.)<br />
<br />
Examples:<br />
* Ideal Mexico<br />
* Glowworm Space Saver<br />
<br />
=== Standard efficiency, fanned-flue, automatic pilot light ===<br />
<br />
A change of building regulations obliged boiler manufacturers to improve the efficiency of their products. A typical boiler of this period has:<br />
* Cast-iron heat exchanger.<br />
* Room-sealed design.<br />
* Fan-assisted flue which allowed for much more versatile flue length and positioning.<br />
* Air pressure switch to ensure fan is running before opening the pilot valve.<br />
* Pilot light ignited automatically by electronic spark ignition.<br />
* PCB with electrics/electronics.<br />
Consequently the boiler's electronics took over from the pilot light and thermocouple the job of sensing that the burners were alight. <br />
<br />
Examples:<br />
* Potterton Profile & Netaheat Electronic<br />
* Potterton Kingfisher MFL <br />
* Baxi Solo2<br />
* Glowworm Fuel Saver and Micron<br />
<br />
=== Standard efficiency, no pilot light ===<br />
<br />
Later standard efficiency models dispensed with the vestigial pilot light inherited from low-efficiency designs and featured direct ignition of the main burner. Such model usually have a modulating gas valve which can vary the gas output under the control of the PCB electronics. Some of the manufacturers began using digital electronics.<br />
<br />
Examples:<br />
* Worcester CBi<br />
* Potterton Suprima<br />
* Baxi Combi, Combi "Eco" (short for "Economy"), Combi Maxflow (storage combi)<br />
* Most Combination boilers without a permanent pilot light that aren't High Efficiency models.<br />
<br />
=== High efficiency, secondary heat exchanger === <br />
<br />
With a move (enforced by a change of building regulations in 2005) to the higher efficiencies, available through condensing the steam present in flue gases back into water, boiler designs changed again. Some designs clearly adapted the technology of standard-efficiency boilers with the addition of a secondary heat exchanger operating on the flue gases of a cast-iron exchanger inherited from a standard-efficiency design. These have tended to be bulkier and/or more tightly-packed internally, sometimes with poor layout where the added components have obviously had to be shoe-horned into a package intended originally for fewer parts. <br />
<br />
All condensing boilers of this type have:<br />
* a condensate waste pipe<br />
* plastic flue pipe (or flue portion of concentric flue assembly) angled back to boiler from outside (in horizontal flue arrangements)<br />
<br />
Examples:<br />
* Baxi Barcelona <br />
* Biasi<br />
* Potterton Suprima HE.<br />
<br />
=== High efficiency, single heat exchanger === <br />
<br />
A typical modern condensing boiler features:<br />
* purpose-designed heat exchanger made of stainless steel, aluminium or other materials<br />
* pre-mix burner: where air and gas are mixed in the correct proportions for combustion and blown into the combustion chamber, often so the flame fires downwards<br />
* modulating burner (by varying the speed of the premix fan). <br />
* syphonic condensate trap storing and dispensing condensate waste in batches rather than a trickle<br />
* Digital electronic controls.<br />
<br />
Examples:<br />
* Alpha CD range of boilers (CDC,CDS,CDX,CDR) [http://www.alpha-innovation.co.uk/products/downloads/brochures/alpha_Full_Range_products_brochure.pdf brochure]<br />
* Baxi Combi HE plus ''(upward firing burner)'' ([http://www.baxi.co.uk/products/literature/Baxi_HE_Plus_Range.pdf brochure])<br />
* Baxi Platinum Combi HE ([http://www.baxi.co.uk/products/literature/Baxi_Platinum_Brochure.pdf brochure] [http://www.baxi.co.uk/products/literature/Baxi_Platinum_Installation_Guide.pdf manual])<br />
* Worcester Greenstar ([http://www.worcester-bosch.co.uk/index.php?fuseaction=site.viewFile&id=129684 brochure] - tech info at end)<br />
* Vaillant Ecomax/Ecotec<br />
* Potterton Promax Combi/System HE plus (a.k.a. "Gold") ([http://www.potterton.co.uk/products/literature/PromaxHE_Plus_brochure.pdf brochure])<br />
* Potterton Promax HE plus Heating ''(upward firing burner)'' (brochure as above)<br />
* Ideal Isar / Icos / Istor<br />
* Keston Celsius<br />
<br />
[[Category:Plumbing]]<br />
[[Category:Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Central_heating_design&diff=18286Central heating design2013-10-14T19:34:00Z<p>John Stumbles: /* Single pipe loop */ attempt to clarify topology etc</p>
<hr />
<div>This article is about [[Central heating]] systems using hot water as a heat-carrying medium. <br />
(Warm-air systems are sometimes found in the UK but their design and installation is not covered here. There is a discussion on updating existing warm-air systems [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/cd973db3a3604624? here])<br />
<br />
The article is intended as a guide to:<br />
* choosing a design for, and installing a new central heating system<br />
* understanding how an existing system is designed, for the purposes of maintaining and fault-finding<br />
<br />
There are separate articles about:<br />
* [[Central heating operation]] for help maintaining a working CH system<br />
* [[Central Heating Repair]] for diagnosing and fixing a faulty system.<br />
<br />
'''''Parts of this article are in skeleton form with main points listed but needing to be expanded'''''<br />
<br />
== Heat requirements ==<br />
In order to get a heating system which works effectively and economically it is important to calculate how much heating power will be required, into the building as a whole (in order to calculate the required size for the boiler or other heat source) and into each room (to calculate sizes of radiators or other heat emitters).<br />
<br />
=== Whole house/boiler sizing ===<br />
For boiler sizing there is a relatively simple yet sufficiently accurate calculation known as the whole-house boiler sizing method. The method is described in the<br />
* [http://www.est.org.uk/uploads/documents/housingbuildings/ce54.pdf Energy Saving Trust worksheet] (PDF)<br />
Online calculators implementing the method are available at:<br />
* [http://www.idhe.org.uk/calculator.html IDHE (Institute of Domestic Heating & Environmental Engineers) calculator] ''(site not available - 10th July 2008)''<br />
* [http://www.est.org.uk/housingbuildings/calculators/boilersizing/ Energy Saving Trust calculator] This calculator is rather cumbersome to use '''and is incorrect for flats (it doesn't discount roof losses)'''<br />
A spreadsheet implementing the calculator is available at:<br />
* [http://yaph.co.uk/heating/boiler_sizing.xls YAPH]<br />
The spreadsheet allows easy what-if calculations showing the effect of, say, cavity wall insulation on the house heating requirements.<br />
<br />
=== Heatloss/radiator sizing ===<br />
For calculating the heat requirements of rooms an elemental approach is taken.<br />
# The area of walls, windows, doors, floor and ceilings is calculated<br />
# U-values for the materials of these elements are found from tables<br />
# Temperature differences across the elements are multiplied by the above figures to calculate total ''fabric'' loss<br />
# The volume of the room is calculated<br />
# The number of air-changes per hour expected for the room is found from a table<br />
# The above two figures are multiplied together with a factor for the heat capacity of air to calculate total ''ventilation'' loss<br />
# The fabric and ventilation losses are added to calculate the total heat requirement of the room, and therefore the size of radiator or other heat-emitter(s) required.<br />
<br />
A (Microsoft Windows) computer program implementing this method is the<br />
* [http://www.quinn-radiators.co.uk/downloads_heatloss.php Barlo heatloss calculator]<br />
<br />
''* Discuss + links to energy conservation articles''<br />
<br />
== Heat Sources ==<br />
<br />
=== Fuels ===<br />
<br />
The most popular fuels for central heating systems are (in order of increasing expense):<br />
# '''Natural Gas'''<br />
# '''Oil'''<br />
# '''LPG''' (Liquefied Petroleum Gas). '''Propane''' and '''Butane''' are LPGs but for heating propane is mostly used. It is often known generically as "Calor" gas (in the same way that vacuum cleaners are known as "Hoovers").<br />
# '''Electricity''' can be used for central heating systems but where it is used for heating it is generally found used with storage heaters using off-peak rate electricity. Where no other fuel is available a system using a [[heat bank]] heated by off-peak electricity with [[Underfloor Heating]] or radiators is likely to be more economical to run than one using storage heaters or any sort of peak-rate heaters. An example of such a system is the "[http://www.gasapplianceguide.co.uk/gledhill_electramate.htm Electramate]" made by [http://www.gledhill.net/ Gledhill]. This is a ready-made package, but similar systems can be designed using other manufacturers' components.<br />
<br />
* '''solid fuel'''s - coal, anthracite etc, and wood or woodchips - are sometimes used to contribute to space and/or water heating. Nowadays they are not usually used as main fuels since most domestic appliances for using them cannot be automatically fed and regulated.<br />
<br />
'''Renewable''' sources such as:<br />
* '''solar thermal'''<br />
* '''geothermal'''<br />
are also increasingly found contributing to heating systems rather than providing sole energy supply.<br />
<br />
=== Appliances ===<br />
<br />
==== Boilers ====<br />
The most common appliances for supplying heat are '''boilers''' using natural gas, oil or LPG to heat "'''primary'''" water. Primary water is water intended for heating rooms via radiators etc or heating "'''secondary'''" water for washing etc (see '''[[Domestic Hot Water|DHW]]'''). Some boilers - known as '''combi''' boilers - heat DHW directly.<br />
<br />
''For further discussion of types of boiler, combi/conventional choice etc see:<br />
*[[Boiler]]s<br />
*[http://www.makewrite.demon.co.uk/BoilerChoice.html Ed's Boiler Choice FAQ]''<br />
<br />
Electric boilers perform the same function as non-combi boilers using electricity. They can be expected to have very high running costs compared to natural gas, oil or LPG boilers.<br />
<br />
==== Ranges ====<br />
'''Ranges''' e.g. '''Aga'''s and '''Rayburn'''s usually heat DHW as a by-product of their cooking functions. They may use natural gas, oil, LPG or solid fuels.<br />
<br />
'''Combined range/boilers''' appear outwardly almost identical to ranges but contain a separate central heating boiler sharing the flue of the cooking range. They may use natural gas, oil or LPG. They are generally non-condensing appliances and therefore less efficient than current central heating boilers (one exception being the [http://www.rayburn-web.co.uk/57_266.htm Rayburn 480 CD] which has a condensing boiler section: this gas-only appliance is only available with a balanced flue).<br />
<br />
==== CHP ====<br />
'''Combined Heat and Power (CHP)''' generators (e.g. '''[http://www.microgen.com/ Microgen]''', '''[http://www.whispergen.com/ Whispergen]''') generate electrical power whilst heating primary water.<br />
<br />
They generate electricity with much lower efficiency than fossil fuel generated electricity supplied by conventional central power stations, but they only generate when heat is wanted, which means all the heat and electricity output is used. This makes the overall picture more efficient than a central power station, where over half the input energy is wasted as heat. So overall the method works out more energy efficient.<br />
<br />
CHP requires non-trivial arrangements for connection into the domestic electricity supply, and financial and administrative arrangements to sell surplus electricity back to the supplier.<br />
<br />
CHP is a well established technology for large facilities, but domestic CHP generators are not readily available in the UK at present (Feb 2007), partly due to concerns about some aspects of the systems and lack of a solid proven track record of domestic CHP or the products on offer.<br />
<br />
==== Solid-fuel back-boilers ====<br />
Traditional coal fires or more modern wood-burning stoves with back boilers can contribute to domestic space or water heating. Their heating output is sometimes combined with that of a main heating boiler by means of a [http://www.dunsleyheat.co.uk/linkupsys.htm Dunsley Neutraliser], although thermal stores can also be used.<br />
<br />
==== Renewable sources ====<br />
<br />
'''Solar thermal panels''' are usually used to provide [[Domestic Hot Water]] (If considering this technology one might also investigate solar warm air systems which may give better energy returns for a given cost: see [[Solar Thermal]].)<br />
<br />
'''Ground-source heat pumps''' provide energy at lower temperatures than are required for DHW and are generally used in space heating systems, often with under-floor heating which can make better use of the lower temperatures generated.<br />
<br />
Both systems, as well as [[Drain Heat Exchanger|waste water heat recovery]], can be used with thermal stores, combining their output with other systems including conventional boilers and/or electric backup heaters to provide space heating, via UFH and radiators, and DHW.<br />
<br />
''' Air-source Heat Pumps ''' - similar benefits as ground-source heat pumps and easier to install; however in locating these units, the potential noise of the fan must be taken into account as some people are very sensitive to such noise, especially at night.<br />
<br />
== Heat Emitters ==<br />
'''''Emitters''' are means of heating spaces: radiators, under-floor heating etc.''<br />
<br />
=== Radiators ===<br />
''"Radiators" actually emit heat mostly via convection rather than radiation: they heat the air which heats the fabric of the room and its occupants.''<br />
<br />
They come in a number of types -- standard panel radiators, Low Surface Temperature (LST), "designer" radiators and towel warmers -- and shapes, sizes and colours/finishes. Radiators must be chosen and located so as to provide sufficient output to heat the spaces they are installed into.<br />
<br />
There is more detail in the article:<br />
* [[Central Heating Radiators]]<br />
<br />
=== Fan-assisted heaters ===<br />
''These types use forced convection, compared to natural convection employed by radiators.''<br />
<br />
Sometimes known as kickspace heaters, these have a fan to distribute air warmed by a water-to-air heat exchanger (typically tubes with fins attached) which transfer heat from the central heating primary water.<br />
<br />
* particularly suitable for small rooms with limited wall space for rads (e.g. kitchen) or too-high heat-loss/floor-area ratio for UFH (e.g. bathroom)<br />
* fast warm-up<br />
* less localised heating effect than radiators; can be effective at heating larger areas<br />
* may feel uncomfortably cold when shut off by thermostat (like electric fan heaters)<br />
* may be too noisy for domestic use in lounges and bedrooms<br />
<br />
=== Underfloor ===<br />
<br />
''This gives radiant heat which warms occupants and fabric directly rather than warming the air.''<br />
<br />
* Requires less total heat output (figures of around 20% are quoted) for a given comfort level compared to radiator-based systems.<br />
* Tends to give warmer feet and cooler heads giving a more comfortable, less stuffy feeling.<br />
* Good for heating large spaces where it would be hard to install sufficient radiators, and spaces with high ceilings e.g. halls where the output of radiators would be lost to the higher parts of the room.<br />
* Limited heat output due to limitation on maximum comfortable floor temperatures which may be insufficient for small rooms with large heat requirements & large losses e.g. bathrooms (although the warmer floors, in conjunction with extra heating from radiators or kick-space heaters, can make for a more comfortable room than one with a cold floor).<br />
* Heat output dependent on floor coverings which need to be chosen to work with the UFH system.<br />
* Slower to heat & cool than radiator based systems, so need better control systems.<br />
* Slow thermal response leads to lower overall efficiency for spaces occupied for relatively short periods, due to the heat lost during the longer warm-up and cool-down periods.<br />
* Hydronic (hot-water) systems generally require lower water temperatures than radiator systems leading to extra complexity and expense (extra pump & thermostatic mixing valve) to run in mixed system with radiators.<br />
* The lower water temperatures required by pure UFH systems enable condensing boilers, solar collectors and heat pumps to operate more efficiently than with radiator-based systems.<br />
* Generally expensive & disruptive to retro-fit to existing building due to need to remove & relay floors (or possibly ceilings below for upper-floor installations).<br />
* Electric UFH is cheaper to install but has higher running costs: popular choice for small bath or shower rooms.<br />
More on [[Underfloor Heating]]<br />
<br />
=== Other radiant ===<br />
Walls can also be used for radiant heating. Usually this is acheived by embedding heating pipework into a solid wall surface. A discussion of the possibility of heating via stud walls can be found [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/3fe720e4cfce3a6d/c2183341d4849b0e here].<br />
<br />
Heating ceilings has the obvious disadvantage of unwanted heat loss upwards; even so one (singularly ineffective) installation is known to [[User:John Stumbles|one of the authors]].<br />
<br />
== Filling arrangements: sealed or vented ==<br />
<br />
The traditional arrangement for maintaining a body of water in the system comprises a '''feed and expansion''' (aka '''header''') tank above the highest point of the system. The tank is kept topped up by a float valve similar to that in a main cold water storage tank or WC cistern.<br />
<br />
Modern systems are usually '''sealed''' with water introduced to the system by a temporary filling hose (or special key-operated device built-in to the boiler). More info can be found in [http://www.makewrite.demon.co.uk/SealedCH.html Ed Sirett's Sealed System FAQ].<br />
<br />
For a completely new system a sealed arrangement is generally preferred, unless it is wished to use a directly heated [[Thermal Store]]. Where an old and poorly-constructed existing system is converted to sealed operation there is the possibility of minor leaks from old radiator valves and poorly-made compression joints leading to relatively rapid loss of pressure and the need to top up the system frequently. For this reason if there is no compelling requirement to convert the system it may be better left alone. Conversely if an open vented system suffers from scaling up of the feed pipe, pumping over of the vent pipe into the feed and expansion tank, microbial sludge growth in the F&E tank or air air-locks when filling up it may be worth converting to sealed operation (provided the boiler is a type for which this is permitted).<br />
<br />
== Configuration: Controls and Zoning ==<br />
<br />
An important aspect of the way a heating system is designed is the way heating is divided into physical zones, and the controls used to regulate heating. These are discussed in a separate article:<br />
* '''[[Central Heating Controls and Zoning]]'''<br />
<br />
== Pipework ==<br />
=== Pipework materials ===<br />
==== Copper ====<br />
<br />
Traditional material.<br />
<br />
Available in various grades and sizes. Those found in domestic CH installations are:<br />
<br />
* Rigid ("Table X") in small-bore sizes: 28mm, 22mm, 15mm<br />
* Fully-annealed (soft) ("Table Y") in micro-bore sizes: 10mm, 8mm<br />
<br />
Features:<br />
* Material usually more expensive than plastics<br />
* Available in lengths 1m, 2m, 3m (also 6m?). 2m and 3m are most common.<br />
* More time-consuming to install<br />
* Requires more lifting of flooring when retro-fitting to existing building<br />
* Small-bore pipes must usually be run in notches in the top of joists: susceptible to damage by nailing and contrary to building regulations.<br />
* Micro-bore pipes may be threaded through holes in joists out of reach of nailing<br />
* Micro-bore pipe may be "cabled" through floor and wall spaces with less disruption in existing building<br />
* May be noisy (e.g. clicking noises) as pipes expand & contract when heating & cooling<br />
* Surface runs can be done neatly avoiding need for boxing-in in certain locations<br />
* Can be joined with solder, compression or push-fit fittings<br />
* Micro-bore may be bent by hand (with external spring) or by small machine for neater bends<br />
* Small-bore may be bent by hand with spring for 15mm (and possibly 22mm if pipe annealed or fitter very strong)<br />
* Small-bore may be bent with large hand-held machine for 15 & 22mm, larger machine on stand for 28mm<br />
<br />
==== Plastic ====<br />
<br />
Some older installations using small-bore (15-28mm) pipework in PVC and ABS may be found but these materials are no longer used for CH pipework.<br />
<br />
Moderm materials (used for last 2 decades or so in UK) are<br />
* PB (Polybutylene)<br />
* PEX (Polyethylene cross-linked)<br />
<br />
Sizes available are:<br />
* 28mm<br />
* 22mm<br />
* 15mm<br />
* 10mm<br />
<br />
Features:<br />
* Pipework usually cheaper than copper<br />
* Pipe available in long rolls e.g. 25m, 50m and 100m<br />
* Easier & quicker to install than rigid pipe<br />
* Pipe may be "cabled" with minimum lifting of flooring in existing building<br />
* Pipes may be run through holes in joists out of reach of nailing<br />
* Pipes expand and sag when hot requiring boxing-in if run on surface<br />
* Can be joined with compression and push-fit fittings.<br />
* Long runs possible with bends in pipework and fewer fittings<br />
<br />
===== Barrier and non-barrier =====<br />
Conventional Wisdom is that only barrier pipe should be used for CH systems as the metallic barrier layer prevents oxygen diffusing through the plastic walls of the pipe into the primary water and causing corrosion in ferrous and possibly other metallic parts of the system - boilers, radiators etc. However [http://www.hep2o.co.uk/ Hepworth Plumbing Products] have stated <br />
in the uk-d-i-y newsgroup that:<br />
<blockquote><br />
If Hep2O Standard pipe has been installed in accordance with our<br />
instructions in a central heating system and one of the recommended<br />
inhibitors used there is no technical reason why it should not continue to<br />
give good service for many decades. [[http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/70540dffa9cf9f4b/34103c153f976739?rnum=1&q=If+Hep2O+Standard+pipe+has+been+installed+in+accordance+with+our&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2F70540dffa9cf9f4b%2Fe2db7ffcad95adb1%3Flnk%3Dst%26q%3DIf+Hep2O+Standard+pipe+has+been+installed+in+accordance+with+our%26rnum%3D1%26#doc_e2db7ffcad95adb1]]<br />
<br />
</blockquote><br />
and<br />
<blockquote><br />
It is now considered by British Gas that central heating systems that<br />
include plastics pipe manufactured to the appropriate British Standard<br />
(such as Hep2O) do not represent a potential corrosion problem from<br />
oxygen ingress where the system water includes an adequate strength of<br />
inhibitor. This applies equally to Barrier and Non-Barrier pipes. [[http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/ff1a4f63c1facf9e/4254068524cd8c4c?rnum=1&q=hepworth+barrier+pipe&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fff1a4f63c1facf9e%2Ff343d48ec0be74b2%3Flnk%3Dst%26q%3Dhepworth+barrier+pipe%26rnum%3D2%26#doc_f343d48ec0be74b2]]<br />
<br />
</blockquote><br />
<br />
However in real life not all central heating systems have effective corrosion inhibition at all times, so barrier pipe is still the preferred option.<br />
<br />
==== Tails ====<br />
<br />
Even in a system using plastic pipe for the main pipe runs the boiler manufacturer usually requires the first 600mm or 1m of pipework connected to the boiler to be in copper.<br />
<br />
Also many installers and/or clients prefer copper tails to radiators rather than plastic. For "designer" radiators or towel radiators in bathrooms chromed radiator tails are often preferred. Since chrome is very hard it is necessary to remove the chrome from the part of the tail pipe being connected into a push-fit fitting since the grab ring of the fitting may not bite securely into the chrome and the fitting may become detatched. It is also necessary to remove the chrome when connecting into a solder fitting since solder may not adhere properly to chrome. If using a compression fitting a brass olive is preferable to a copper one since the olive has to slightly compress the pipework to secure the fitting and the chrome may be too hard for a soft copper olive to acheive the necessary pressure.<br />
<br />
=== pipework layout ===<br />
==== pipe sizes v. heat-carrying capacities + noise ====<br />
<br />
==== Single pipe loop ====<br />
<br />
This arrangement is not used for current designs but may be found in older installations (e.g. 1960s and early 1970s), and it may be required to extend such systems.<br />
<br />
The general topology is a single pipe run in a loop from the boiler's flow back to its return (via a circulating pump) with the radiators connected into the pipe loop via plumbing Tees (sometimes swept Tees). This arrangement is usually immediately obvious as the main loop pipe runs underneath the radiator. Although one might expect all the heating water to take the more direct route through the pipe, enough rises into the radiator, travels along it (losing heat as it goes) and sinks back to the main pipe at the other end to keep the radiator hot and emitting heat.<br />
<br />
This arrangement means that radiators further from the boiler's flow / closer to the return end of the loop run at slightly lower temperatures than those at the flow end so should be oversized to give their desired output at their reduced temperatures. Also the circulating pump for a single pipe loop is doing a certain amount of work just circulating water through the pipes so less of its effort is available for circulation through the radiators.<br />
<br />
Where it is necessary to add, say, one or two extra radiators to such a system they can be added into the existing loop (allowing for over-sizing if they are at the cooler return end of loop). However if many extra radiators are to be added it may be better to divide the system into two (or more) separate loops if possible (or to add a separate normal 2-pipe loop, perhaps as a separate zone).<br />
<br />
==== Tree: trunk + branch ====<br />
A good pipework arrangement has 'trunk' pipes from the boiler in 22mm (or 28mm depending on the output of the boiler and the manufacturer's instructions) with branches in 15mm (or microbore: 10mm or 8mm) to individual radiators. Pipe sizes can be stepped down from trunks through branches e.g. <br />
<br />
[[Image:Trunk-branch.gif]]<br />
<br />
==== Microbore ====<br />
<br />
The topology of a microbore installation is usually a tree with trunks of 22mm and branches of 10mm and/or 8mm pipework, and is inherently well-balanced.<br />
<br />
The fully-annealed ("Table Y") copper pipe (or flexible plastic pipe) used for the microbore sections can be bent and threaded through stud walls and joists unlike rigid copper in small-bore sizes.<br />
<br />
Some clients may prefer to have 15mm tails to radiators (joined to microbore under the floor or in the wall) for the sake of appearance.<br />
<br />
There is an article on [[Fitting_TRVs_to_Microbore|retro-fitting 15mm radiator valves to microbore]].<br />
<br />
Limited power throughput (2.5kW-ish)<br />
<br />
Narrow bore is more vulnerable to sludge.<br />
<br />
==== Dual loop ====<br />
inherently balanced but rarely practicable<br />
<br />
==== Random ====<br />
An arrangement with radiators connected with widely varying lengths of narrow-bore pipework is bad for balancing but sometimes necessary especially when extending an existing system where access under floors etc is limited.<br />
<br />
== Installation ==<br />
=== Routing ===<br />
The choice of routes for the pipework may have to incorporate a number of criteria. These may be aesthetic, cost or performance based. For instance, the performance considerations will urge you avoid routing through unheated spaces or a zone differing from the one to be heated. The cold space below a suspended ground floor is not a natural performance choice and requires effective insulation but is an overwhelmingly good choice from the cost and aesthetic aspects.<br />
<br />
Typically there are general approaches depending on the structure of the floors.<br />
* All floor(s) suspended: Main pipes run vertically between floor(s) in one place (often a corner near the boiler). Plastic pipe is a great choice as it can be cabled through joists and readily installed in runs between joists; it is also out of sight, has fewer joints and lower heat losses. Copper/chrome tails emerge through floor to supply radiator from below.<br />
* Ground floor is solid other floor(s) are suspended: The upper floors or even the loft space (for a bungalow) are used as above and also to supply the radiators in rooms below. Groups of one to three radiators (or perhaps more) are supplied from above by a pair of pipes. Each group will need a drain off point. Pipes drops are on show but can be hidden in a duct but this can make a feature out of a necessity, there will still be runs under the radiator.<br />
* All solid floors and ceiling: Copper pipes are run round at skirting board height from room to room, going through internal walls as needed. This usually leads to a inferior layout topology so needing extra care to balance the system. The entrance door is often an obstacle; it can be unsightly to go over and across and down, and that leads to the needs for air bleed points, ideally at the top of each down flowing pipe, this is a further draw back. It is often best to bite the bullet and dig the concrete up to cross under the doorway and accept that such sites have difficulties. <br />
* New build: Apart from the possibility of underfloor heating there is also the oportunity to install microbore plastic behind dry lining boards.<br />
<br />
* installation in solid floor<br />
<br />
==== Joist Notching ====<br />
Building regs impose restriction on the places and sizes for notches and holes in joists. <br />
Notches must be no more than 12.5% of joist depth installed between 10% and 25% along the spans length. <br />
The best way to cross joists is through holes bored in the middle of joists. Microbore can be cabled through, about 4 or 5 joists seems to be the maximum number that can be crossed by any single length. Flexible plastic pipe is a very welcome material in these cases, even then a good right angled joist boring drill or cordless equivalent is a must for this part of the job. Rigid pipework has to be installed in notches, which should be placed in the middle of the floor board. <br />
==== Drain-off points ====<br />
It is certainly good practice, if not manadatory, to install drain off points on the lowest points of the pipework.<br />
Ideally the best place is outside over a gully. Some radiator valves include a built in drain tap. There are two types of fittings on is known as heavy and light pattern. The heavy type have a seal around the spindle they are a little less messy when in use. There is no reason why you could not use ball-o-fix service isolators although this does not seem to be common practice. <br />
<br />
* plastic v. copper or chromed pipetails<br />
** play in tails<br />
* pressure testing<br />
* flushing<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Wedged_joint&diff=16313Wedged joint2012-04-03T16:18:44Z<p>John Stumbles: /* Add a taper */ s/flair/flare/ (and remove unnecessary commas)</p>
<hr />
<div>Mortice and Tenon joints are one of the mainstays of many of carpentry and cabinet making jobs. This article shows a very simple technique for enhancing the holding power of a joint like this, and making it almost impossible to pull out. <br />
<br />
==Add a taper==<br />
Once the mortice is cut use a chisel to add a slight taper to the outside cheeks of the mortice (i.e. the part of the joint furthest from the shoulder of the tenon):<br />
<br />
[[image:CuttingTaperWithChisel.jpg]]<br />
<br />
If we look inside the joint you can see that aim is to add a flare to the exit of the tenon:<br />
<br />
[[image:CuttingTaperXray.jpg]]<br />
<br />
==Cut the tenon==<br />
The next stage is very simple, simply run a saw cut down the ends of your tenon, around half an inch in from the edges:<br />
<br />
[[image:TenonsOnShowRealWood.jpg|640px]]<br />
<br />
<br />
==Glue up and assemble==<br />
Glue up and assemble the joint in the normal way, clamping tight if required. Looking at the end of the joint, you should see a gap either side of the tenon where you have added the taper with the chisel:<br />
<br />
[[image:TenonBeforeWedging.jpg]]<br />
<br />
==Wedge the joint==<br />
Make sure you have enough [[Wedges|wedges]] pre-cut to complete the joint:<br />
<br />
[[image:HardwoodWedges.jpg]]<br />
<br />
Now apply a generous amount of glue to the points of each wedge and poke into the slot you cut in the tenon:<br />
<br />
[[image:GluedupWedges.jpg]]<br />
<br />
Drive the wedges home with a hammer. Do all the edges in a tenon at the same time - alternating between them, rather than driving one completely before moving to the next. As you drive them home, you should see the gap at the ends of the mortice vanish as the edges of the tenon are forced out into the flared section of the mortice:<br />
<br />
[[image:WedgesDrivenIn.jpg]]<br />
<br />
This will mean that the tenon will no longer pull out of the mortice due to the mechanical interlock - its a strong joint even without glue. <br />
<br />
Allow the glue to dry, and cut off any protruding wedges flush with the end of the joint:<br />
<br />
[[image:CuttingWedgeFlush.jpg]]<br />
<br />
Then plane the whole lot level to leave the whole joint clean:<br />
<br />
[[image:PlaneWedgesOff.jpg]]<br />
<br />
You now have a joint that will not be coming apart any time soon! It is also far stronger than a normal M&T joint when under tension. <br />
<br />
==Blind Mortices==<br />
The same technique can also be used on a blind mortice (i.e. one that does not go right through the timber). However the process of wedging is slightly different, since you can't hammer them in from the end. <br />
<br />
For a blind joint, cut your wedges slightly shorter, so that you know the full length of the wedge will fit the joint. Also cut your taper in the mortice such that it tapers along most of the side of the mortice. Glue up and poke the wedges into the cuts in the tenon, before assembly. Now carefully insert the tenon into the mortice - the backs of the edges going in first. The wedges will "bottom out" in the mortice. At this point drive the whole tenon section into the mortice with a mallet. As the tenon is driven into the joint, the wedges will be driven into their slots, and the tenon will start to spread. Hopefully (if you have judged the taper angles right to match the wedges), the joint will go home, and will be nicely spread to match your taper. <br />
<br />
You don't get any second chance at this one, once its in, its staying - even if you forgot the glue. <br />
<br />
<br />
==See Also==<br />
<br />
:*[[Large tenon jig]] <br />
:*[[Wedges]]<br />
<br />
[[category:building]]<br />
[[category:construction]]<br />
[[category:wood]]<br />
[[category:doors]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Thermal_Stores_and_Heat_Banks&diff=15725Thermal Stores and Heat Banks2012-01-15T23:09:08Z<p>John Stumbles: replace external links to image files with links to local copies</p>
<hr />
<div>'''Thermal stores''' and '''heat banks''' provide hot water at mains pressure, giving excellent performance from showers and spray mixer taps. They don't require bulky tanks in the attic, which can free up space. <br />
<br />
[[Unvented_DHW|"Unvented"]] (e.g. "Megaflo") systems also give these benefits but their installation has to be notified under [[Building Regulations]] and they must be serviced annually for safety, so thermal stores are particularly attractive for DIY-ers.<br />
<br />
Thermal stores are also used in applications where heat sources are combined, e.g. mixing solar or solid fuel with conventional boilers, and sometimes also for supplying underfloor heating systems alongside radiators.<br />
<br />
For a detailed discussion of thermal stores and heat banks in comparison with gravity and unvented systems please see the article on<br />
* [[Domestic Hot Water Systems]]. <br />
That article also introduces some of the concepts used in this article:<br />
* [[Domestic Hot Water Systems#Direct and Indirect systems|Direct and Indirect systems]]<br />
* [[Domestic Hot Water Systems#Primary and Secondary|Primary and Secondary water]]<br />
* [[Domestic Hot Water Systems#Stratification|Stratification]]<br />
* [[Domestic Hot Water Systems#Recovery|Recovery]]<br />
<br />
== How they work ==<br />
<br />
[[Image:Thermal_Store_DPS_Pandora_rectangular_in_alcove.jpg|frame|Rectangular-section Thermal Store installed in an alcove]]<br />
<br />
A container of water is heated by the boiler or immersion heater etc. Mains pressure cold water passes through a [http://en.wikipedia.org/wiki/Heat_exchanger heat exchanger] where it is heated by the stored hot water and supplies the taps etc. The thermal storage container itself is under low pressure, sometimes only a head of a few centimetres of water. With very low pressures the container does not have to be cylindrical but can easily be made in other shapes such as a rectangular section, which can make better use of the space they are installed into. (However for the sake of clarity they are referred to here as '''cylinders'''.)<br />
<br />
In a classic thermal store the heat exchanger is a coil of pipe with a large surface area within the cylinder itself. As cold water flows through the coil it is heated by the hot water surrounding it and as the surrounding hot water cools it sinks by convection bringing hot water from elsewhere in the cylinder into contact with the coil. <br />
<br />
In another type of system, sometimes referred to as a heat bank, the heat exchanger is external to the hot water cylinder. When DHW is required hot water is pumped through the heat exchanger and back into the cylinder. The pump is usually controlled by a switch in the DHW pipework which senses when water is flowing to the hot taps etc. In this type of design the heat exchanger is usually a type comprising several plates of copper joined in a sort of multi-layer sandwich, known as a Plate Heat Exchanger (PHE).<br />
<br />
{| border="1" cellpadding="20" cellspacing="0"<br />
!Thermal Store<br />
!Heat Bank<br />
|-<br />
|[[image:Thermalstore.jpg]]<br />
|[[Image:heatbank.jpg]]<br />
|}<br />
<br />
''In this document when comparing the two types of system we refer to them as '''thermal stores''' and '''heat banks''', but elsewhere (e.g. when comparing these kinds of system with unvented and conventional) we refer to them generally as thermal stores.''<br />
<br />
== Thermal Stores and Heat Banks: Pros and Cons ==<br />
<br />
Clearly a Thermal Store, with its internal heat exchanger and no moving parts, is simpler than a Heat Bank, with its pump, heat exchanger and flow switch. On the other hand Thermal Stores may be more prone to [[Limescale|scaling-up]] in [http://en.wikipedia.org/wiki/Hard_water hard water] areas. When there is no demand for DHW the water in the heat exchanger coil is raised to the temperature of the Thermal Store, whereas in a Heat Bank the heat exchanger cools towards ambient temperature when there is no DHW demand. Also, even if the heat exchanger of a Heat Bank does become scaled up it can be removed for descaling or replaced if unserviceable, whereas the heat exchanger of a Thermal Store is an integral part of the appliance.<br />
<br />
Since the heat exchanger and pump are outside the heat bank they can be sited remotely from the bank, closer to the point of use if wished, reducing hot water delivery delay and wastage of water and heat due to the "dead leg" of cool or cold water in the DHW pipework. One can also have multiple heat exchangers drawing from the same heat bank, e.g. supplying widely-spaced locations requiring DHW from a '''heat main''' carrying hot primary water around the building in well-insulated pipework to instantaneous DHW heat exchangers close to the points of use. Such a heat main may also supply radiators, UFH etc so that only one pair of pipes is required to cover the whole area of the installation for both heating and hot water. This sort of arrangement is also suited to space heating with multiple zones.<br />
<br />
A Heat Bank may be built out of fairly standard components rather than as a custom assembly, making it attractive for [[DIY Heat Bank|DIY]].<br />
<br />
Another difference between Thermal Stores and Heat Banks is in how efficiently they use the amount of hot water they contain to provide DHW. This concerns stratification and mixing of water in the store, explained [[#Stratification|in the box below]]. The net effect is that a Heat Bank must have a higher capacity than a Thermal Store to provide the same quantity of DHW (if all other factors are equal).<br />
<br />
<br />
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== Stratification ==<br />
<br />
Assume (for the sake of illustration) that <br />
* the water in the store reaches 70&deg;C when fully heated<br />
* the incoming cold water is at 10&deg;C<br />
* the hot water must be at least 40&deg;C to be acceptable<br />
* the heat exchanger is perfect, i.e. there is no temperature drop across it. <br />
<br />
As DHW is heated it will rise to 70&deg;C (when the store is fully heated) and will cool the water in the store to 10&deg;C. If the cooled water is thoroughly mixed with the hot water the whole store will progressively cool until it reaches 40&deg;C after which the temperature of the DHW becomes unacceptably cold. However if the water cooled to 10&deg;C is kept separate and only the water at 70&deg;C is fed to the heat exchanger then the DHW will continue to produce acceptably hot water until the whole store contains only water at 10&deg;C. In the first scenario the amount of heat available by cooling the store from 70&deg;C to 40&deg;C is available for heating DHW, while in the second the amount of heat available is that of cooling the store from 70&deg;C to 10&deg;C. This gives much more DHW for a given volume of store at a given temperature. Stratification, where the cool water at the bottom of the store remains relatively separate from the hotter water further up, provides a means of approaching this goal.<br />
<br />
Circulation of water in a a thermal store is driven by convection currents caused by the cooling effect on the stored water of the cold water flowing through the heat exchanger. These convection currents are relatively gentle, and proportional to the amount of heat being drawn from the store. Thus the cooled water tends to fall gently to the bottom of the store leaving hotter water higher up, nearer the heat exchanger. As the store continues to supply heat to DHW the cooler layers of water extend further up the cylinder until at some point, when much of the heat exchanger is surrounded by cooler water, the temperature of DHW drops below 40&deg;C. At this point there will still be some hot water near the top of the cylinder, so the thermal store is not using the stored hot water with perfect efficiency.<br />
<br />
In a heat bank water can be drawn from the very top of the cylinder to pass through the heat exchanger, so all the stored hot water should be available for heating DHW. Unfortunately most DHW heat banks use a simple fixed-speed central heating circulator switched by a flow switch in the DHW pipework. This has to provide sufficient flow through the heat exchanger to provide satisfactory DWH temperature at maximum DHW flow rate, so even when the demand is less the pump is still circulating water at its maximum rate. This causes unnecessary mixing in the cylinder, destroying stratification. This disadvantage is not inherent: it would be possible to control flow rate through the heat exchanger to the rate necessary to give the required DHW temperature. This could be done either electronically, by controlling the pump speed, or mechanically by restricting the flow through the pump and heat exchanger (e.g. by a mechanism similar to that in thermostatic radiator valves).<br />
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<br />
== Recovery ==<br />
<br />
Conventional cylinders used with boilers and central heating systems are indirect types because the primary water must be kept free of oxygen and may be treated with corrosion inhibitor and other chemicals. However in thermal stores and heat banks the water in the cylinder heats DHW indirectly through a heat exchanger so the water in the store can be the primary water shared with the boiler etc. This allows the store to recover as fast as the boiler can generate heat. Also, since there is no temperature drop between the boiler and the stored water (as there is across a primary heat exchanger) the boiler can run at a lower temperature to keep the store at its desired temperature. This allows slightly greater efficiency of operation with high-efficiency condensing boilers.<br />
<br />
This arrangement does, however, require that the primary circuit be vented (since an unvented system would place the storage vessel under pressure, as in unvented DHW systems). In practice this means a small header tank is required above the highest point in the system i.e. above any radiators on the top floor.<br />
<br />
<br />
----<br />
<br />
<br />
== Configurations ==<br />
<br />
Four common configurations of thermal store are:<br />
<br />
{| border="1" cellpadding="20" cellspacing="0"<br />
!External header tank<br />
!Internal header tank<br />
|-<br />
|[[Image:Thermal_Store_Direct_Cylinder_150.jpg]]<br />
|[[Image:Thermal_Store_Direct_Combi_150.jpg]]<br />
|-<br />
| colspan="2" align="center" |'''Direct: electric only or sharing primary water with boiler'''<br>&nbsp; <br />
|-<br />
|[[Image:Thermal_Store_Indirect_Cylinder_150.jpg]]<br />
|[[Image:Thermal_Store_Indirect_Combi_150.jpg]]<br />
|-<br />
| colspan="2" align="center" |'''Indirect: thermal store separate from boiler's primary water'''<br>&nbsp; <br />
|}<br />
<br />
=See Also=<br />
* [[Domestic Hot Water Systems]]<br />
* [[Unvented DHW]]<br />
* [[Central Heating Design]]<br />
* [[DIY Heat Bank]]<br />
* [[Solar Thermal]]<br />
* [[Underfloor Heating]]<br />
* [http://www.gledhill-repairs.co.uk/ Gledhill thermal store product info] (independent site run by heating engineer [http://www.miketheboilerman.com/ Mike Bryant], not by Gledhill).<br />
<br />
<br />
[[Category:Plumbing]]<br />
[[Category:Heating]]<br />
[[Category: Domestic Hot Water]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=File:Thermal_Store_Indirect_Combi_150.jpg&diff=15724File:Thermal Store Indirect Combi 150.jpg2012-01-15T23:07:16Z<p>John Stumbles: </p>
<hr />
<div></div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=File:Thermal_Store_Indirect_Cylinder_150.jpg&diff=15723File:Thermal Store Indirect Cylinder 150.jpg2012-01-15T23:06:54Z<p>John Stumbles: </p>
<hr />
<div></div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=File:Thermal_Store_Direct_Combi_150.jpg&diff=15722File:Thermal Store Direct Combi 150.jpg2012-01-15T23:05:28Z<p>John Stumbles: </p>
<hr />
<div></div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=File:Thermal_Store_Direct_Cylinder_150.jpg&diff=15721File:Thermal Store Direct Cylinder 150.jpg2012-01-15T23:04:22Z<p>John Stumbles: </p>
<hr />
<div></div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Showers&diff=14763Showers2011-02-08T11:44:11Z<p>John Stumbles: /* Separate pump */ typo</p>
<hr />
<div>Showers are increasingly popular in British homes: what was rather exotic and luxurious in the day's of [http://en.wikipedia.org/wiki/Barry_Bucknell "Barry Bucknell's Do It Yourself"] is now a standard fitting in new houses. However, since much of Britain's housing stock still has nothing more sophisticated than a Boots' rubber hose hairwashing attachment pushed onto the bath taps, putting in a 'proper' shower is a popular DIY project.<br />
<br />
Showers may range from a bath/shower mixer tap with a shower head on a peg on the wall over the bath, to a multi-jet full-body massage shower with drencher heads and diverter valves in a walk-in enclosure in a wet room.<br />
<br />
This article is about designing and installing showers so that they give satisfactory performance to the users. It is not about the aesthetics of showers, except inasmuch as aesthetic choices cannot be made in isolation from technical considerations e.g. how much water is required to supply that dinner-plate-sized drencher shower head and multi-body-jet system.<br />
<br />
== Shower performance ==<br />
<br />
The main factors affecting how satisfactory a shower's performance is are:<br />
<br />
=== Pressure ===<br />
<br />
The force with which water comes out of the shower head (or whether water comes out at all!) depends on the pressure of the hot and cold supplies: whichever has the lower pressure will be the limiting factor. If the pressure available from the existing water supplies is too low it may be possible to boost it with a [[#Pumps|pump]].<br />
<br />
=== Flow ===<br />
<br />
The rate at which water comes out of the shower is determined by the pressure and other factors. In particular it may be limited by whatever is heating the water. Higher flow rates are better for washing (e.g. rinsing off soap or shampoo) and warming (or cooling) the body, but consume more water and energy. The energy conveyed by water at high pressure and high flow rates has a physical effect on the skin which some users may find stimulating but others may find uncomfortable.<br />
<br />
=== Temperature ===<br />
<br />
How well the temperature is controlled depends on the design of the shower valve and the characteristics of the hot and cold water supplies. Thermostatic valves make it easier to set a comfortable temperature, and the temperature tends to remain constant despite changes in temperature and pressure of the water supplies. However some types of valve are better than others at keeping the temperature constant during brief fluctuations such as when other taps connected to the supplies are turned on or off.<br />
<br />
==Hot and cold water supplies==<br />
<br />
As indicated above, for a shower to give good performance the type of hot and cold supplies must be known and taken into consideration in choosing the type of shower to be installed.<br />
<br />
===Types of hot water systems===<br />
<br />
(See also [[Domestic Hot Water Systems]])<br />
<br />
For the purposes of shower design an important distinction is between systems supplying hot water at mains pressure those supplying at low pressures.<br />
<br />
==== Mains pressure systems ====<br />
<br />
In most circumstances the pressure available from the mains is more than enough for satisfactory showers. However the flow - which may be limited by the heating source (and other factors) - may be less satisfactory. The main types of mains pressure hot water systems are:<br />
<br />
; Gas instantaneous<br />
: ''Typically from a [[boilers|combi]] boiler, or a multipoint ('Ascot' type) water heater''<br />
: The flow rate from these sources is satisfactory for normal showers (but may not be for whole-body, multi jet or drencher types). However when other users also draw hot water the supply to the shower will be reduced to some extent. To what extent depends on the power rating of the boiler and on the relative resistances of the pipework to the shower and to other outlets. A 40kW combi will supply about 66% more hot water than a 24kW unit, but neither may be satisfactory if another outlet (e.g. a bath tap) is capable of drawing the entire output of the combi. Conversely even the smaller combi may be satisfactory if the resistance to other outlets is high enough (or made artificially so by partly closing service isolation valves) for the shower always to receive good pressure.<br />
: Another problem which may occur with these systems is that the boiler or water heater may cut in and out at low flow rates, which can result in the shower going hot and cold. This tends to be a problem more with older boilers which cannot modulate their output down to low rates. To test whether this is likely to be a problem before installing a shower onto such a system one can run a hot water tap at low rates and feel whether the water alternates hot and cold.<br />
<br />
; Stored<br />
: ''These are found as [[unvented DHW|unvented cylinders]] (e.g. "Megaflow") and [[Thermal Store|thermal stores or heat banks]] (e.g. "Pandora" or "Boilermate" units)''<br />
: The flow rate from these is practically unlimited (although the total quantity of hot water available before the store runs cold is limited to, typically, several showers in succession). They are usually found in more upmarket installations designed to supply multiple baths and/or showers simultaneously.<br />
<br />
'''"Storage combis"''' have a small built-in storage vessel and typically can supply high flow rates, like other stored systems, but for shorter times. Thus they perform better than plain combis when short demands for additional DHW are made (e.g. filling a sink) and they may be able to run two showers more or less continuously. However when their internal store is depleted (e.g. when filling a bath) the output reverts to that of a standard combi, thus they are not ideal for installations serving baths and showers simultaneously.<br />
<br />
; Electric showers<br />
: These are a special case of mains pressure hot water supply as the water is heated inside the shower unit itself (or occasionally in a separate unit connected to the shower head and controls). Although the entire output of the heater is dedicated to the shower the heat input is limited by electrical considerations and is typically one third to one half that of even the smallest combi boiler. The amount of hot water they give may be found unsatisfactory by those used to showers heated by other methods, especially in winter when the flow is lowest due to the low temperature of the incoming cold water.<br />
<br />
==== Low pressure systems ====<br />
<br />
Traditional, conventional systems with a hot water cylinder (other than "Megaflow" etc as described above) give water at low pressure, which is usually insufficient for a shower unless boosted in some way (see discussion of [[#Head|head]]). They may be part of a CH system and/or heated by electric immersion elements (including night storage "Economy 7"-type systems).<br />
<br />
===== Head =====<br />
Without augmentation by a pump the pressure ('''head''') of water available is determined by the difference in height between water level in the storage tank and the height of the shower head. '''The position of the hot water cylinder itself is immaterial''' (although if the tank and the cylinder are part of a single package they will obviously be closely related). The horizontal distance between CW tank and shower does not affect the pressure either (though long pipe runs, and the size of pipework and other constrictions will affect the possible flow rate).<br />
<br />
If the water level in the tank is lower than the shower head the pressure will be negative and shower simply will not work without a pump.<br />
<br />
As a rule of thumb a head of less than 1-2 metres is unlikely to give a satisfactory shower (depending on the expectations of the user), even with short runs of wide-bore pipework and appropriate valves and shower head. Over 3 metres gravity-fed showers may be satisfactory (e.g. with a tank in the attic and a shower on the floor below the top floor).<br />
<br />
=== Pumps ===<br />
<br />
Whether it is possible to fit a pump, and what type, depends on whether the cold water storage is:<br />
<br />
'''separate''' - with a large (rectangular or cylindrical) tank, usually in the attic<br />
: it is usually possible to fit a pump to this type of system with both hot and cold supplies derived from the tank and boosted by the pump, allowing a choice of [[#Power shower|packaged "power shower"]] or [[#Separate pump|standalone pump]].<br />
'''packaged''' - with a cuboid CW tank above the HW cylinder usually in a frame<br />
: depending on the construction of the package it may not be possible to arrange a cold feed from the tank so a shower which can accept unequal pressures (with the cold supplied directly from the mains) will be required.<br />
'''combined''' - ''("'Fortic" type)'' with a small cylindrical CW storage vessel directly on top of the HW cylinder<br />
: these systems have very small cold water storage tanks so any pump fitted may be subject to running dry; also as for packaged systems a low-pressure cold water supply will not be available. Venturi-type showers can be used. If an electric pump on the hot feed is used the float valve to the cylinder's header tank can be replaced by an equilibrium type (e.g. Torbeck) for quicker filling and the flow to the shower restricted to ensure that the tank can refill as fast as water is drawn for the shower.<br />
<br />
When a pump is required and a cold feed from the storage tank is available (see above) the choices are an integral "power shower" or a separate pump and a normal shower mixer valve.<br />
<br />
==== Power shower ====<br />
This contains a pump and a mixer valve (thermostatic or manual) in a combined unit. This may be a box mounted on the wall (looking similar to an electrically-heated shower unit) or outside the shower area, connected to the shower head and a control (e.g. Aqualisa Quartz)<br />
<br />
==== Separate pump ====<br />
Standalone pumps may be<br />
; single ended<br />
: pumping just one supply (usually the hot)<br />
; double ended<br />
: pumping hot and cold<br />
There are also choices of<br />
; mains voltage<br />
: these may not be installed in certain locations within bath or shower rooms due to [[electrical regulations]]<br />
; low voltage<br />
: these are run from a transformer mounted remote from the pump so the latter may be located within restricted zones in the bath/shower room.<br />
<br />
Integral power showers may also have separate low voltage transformers.<br />
<br />
Pumps are usually quite intolerant of being run dry so it is important to prevent this happening.<br />
<br />
==== Negative head ====<br />
<br />
Where there is no (or negative) head of water to the shower and a pump is to be used the options are<br />
* A pump with a manually operated switch to start it running<br />
: These usually have an air-pressure operated switch at the pump connected by plastic tubing (about 6mm diameter) to a push-button which can be mounted inside the shower enclosure. The tubing can be many tens of metres long. Once the push-button-operated switch has started the pump its built-in flow-sense switches keep it running until the shower valve is closed, when it stops running.<br />
<br />
* A '''negative head''' pump<br />
: These maintain a boosted pressure at their outlets at all times. When no water is being drawn they do not need to run and a small expansion vessel built-into the pump maintains the pressure until a demand for water causes the pressure to drop and the pump to run again.<br />
<br />
==== Cold supply to pump ====<br />
A double-ended pump or power shower (in which both hot and cold water supplies are pumped) requires a supply of cold water at the same pressure as the hot. Where the hot water is supplied from a cold water storage tank in the attic the shower's cold water supply is taken from the same tank. Sometimes there is already a tapping on the tank for supplying the bath cold tap and possibly other services. If there is not (or the existing tapping is unsuitable) a new tapping can be made. This should be lower than the tapping supplying the hot water system so that if the tank empties the hot feed will be lost first, to avoid scalding the shower user. (Where a second tapping would be too low on the tank a new tapping can sometimes be made higher up and used to supply the existing [[DHW]] system with the existing tapping used for the pump cold feed.)<br />
<br />
Where the hot water system has a pre-packaged tank and cylinder with a sizeable tank it may be feasible to make a second tapping on the tank for the pump. However 'Fortic'-type combination cylinders have very small tanks and are not suitable for taking additional tappings off. Even supplying only DHW these types are liable to quickly run dry if supplying heavy demands, so if being used with a shower pump care should be taken to ensure that the tank's filling valve can refill the tank as quickly as the shower draws from it.<br />
<br />
==== Unequal supply pressures ====<br />
Some shower valves are suitable for use with hot and cold supplies at differing pressures. In this case a single ended shower pump (or double-ended with both sides plumbed in parallel) can be used to boost the hot water pressure, with cold water fed from the mains.<br />
<br />
==== Venturi shower mixers ====<br />
A special case of unequal pressure shower valve, the venturi shower uses the energy of mains pressure cold water to boost the flow from a low pressure hot supply to provide a reasonable pressure and flow of shower. It is a power shower which does not require an electricity supply.<br />
<br />
=== Boosting supplies to other outlets ===<br />
<br />
Where a pump is necessary to supply a shower it is often desirable to also boost the supply to other outlets. For example where a bath or shower room has been created in an attic there may be insufficient pressure to give satisfactory flow at basin taps, particularly with modern monobloc mixers designed for high pressure supplies. In situations such as this the hot supply to the basin mixer (and possibly also to bath taps) can be taken from the shower pump. However this may give unsatisfactory operation with standard flow-actuated pumps since, as the tap is opened, there will at first be a slow flow at the un-boosted pressure and then, when the flow is sufficient to trigger the pump, a sudden surge at the boosted pressure. If the user is trying to get a comfortably mixed flow from a basin mixer, or a modest flow from a separate tap, the pump's switching in and out may cause problems. In these situations a negative head pump - which acts to present a constantly boosted pressure at its outlets - may be better.<br />
<br />
=== Home booster pump ===<br />
<br />
An alternative where boosted pressure is required for other outlets besides showers is the Grundfos Home Booster. This is similar to a central heating circulator (pump) but designed for pumping potable water, with a flow-operated switch like shower pumps. It is in effect a single-ended pump. It is quieter and probably longer lasting in applications requiring frequent service (e.g. where services such as kitchen taps will be supplied).<br />
<br />
[[Category:Domestic Hot Water]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=User_talk:NT&diff=14762User talk:NT2011-02-07T22:39:34Z<p>John Stumbles: </p>
<hr />
<div>please see [[Talk:ZZ_001]] --[[User:John Stumbles|John Stumbles]] 15:42, 21 April 2007 (BST)<br />
<br />
== Deletion discussion ==<br />
<br />
discussion continued from Talk:ZZ 001<br />
Quotes John Stumbles:<br />
<br />
"like the sorcerer's apprentice with the bloody buckets and brooms!"<br />
<br />
hehe<br />
<br />
<br />
"OK he's done that: you and I are now superhero^H^H^Husers :-)."<br />
<br />
Let us tread carefully then. Mods are unfortunately the biggest cause of online forum failure.<br />
<br />
<br />
"I suggest we tread carefully with deleting things:"<br />
<br />
I quite agree to that, and suggest we discuss all potential deletions before removing. Except for spam, there is really no hurry, and quick deletions can and sometimes do demotivate contributors.<br />
<br />
I'm all for giving people time to respond. If we give all contributors every opportunity it minimises the chance of us causing problems unexpectedly, which mods can all too easily unintentionally do.<br />
<br />
Getting a deleted article back is easy if one saves a copy with its wikicode.<br />
<br />
Where to discuss potential deletions? How about in the talk page of the article concerned? This is as easy if not easier than anywhere else, it alerts any other contributors to that article, and is the same space as other issue discussion, which may be relevant to the question of deletion sometimes.<br />
<br />
: ''agreed''<br />
<br />
The last question is where to put this discussion! I guess wherever it goes we'll both see it.<br />
[[User:NT|NT]] 10:39, 22 April 2007 (BST)<br />
<br />
: Here will do for starters, but there is also the parallel universe of the DIYWiki namespace (where pages like [[Project:Copyrights]] lives). I've created [[DIYWiki:Test page]] and [[DIYWiki talk:Test page]] which don't show up on [[Special:allpages]] unless you select the DIYWiki namespace.<br />
:<br />
: BTW I also blocked a spammer [[User:122.32.70.165]] - not the usual range of IP addresses for Mr Dodgypharms. My guess is that these things are generated by [http://en.wikipedia.org/wiki/Spambot spambots] (of the last type) running off compromised users' machines. Considering also that the keymachine.de users were probably on dynamic IP addresses I set up a temporary block for 1 month. Hopefully by the time that's expired the user's IP address will have changed (we'll know when we get the next spam from a different IP!) and I didn't want to leave a block in place indefinitely on what might eventually be an innocent new user's IP.<br />
:<br />
: --[[User:John Stumbles|John Stumbles]] 12:08, 22 April 2007 (BST)<br />
<br />
== Spam ==<br />
<br />
Do you think it might be worth clearing and protecting some of the pages like the disclaimer one that they keep creating? Save having to endlessly delete it?<br />
<br />
Also have you noticed we have quite a long user list of fairly obvious spammy user IDs?<br />
<br />
--[[User:John Rumm|John Rumm]] 12:45, 23 February 2008 (GMT)<br />
<br />
<br />
If we protect a page I think they'll just use another one, so I'm not sure we'd be further forward. I did spot an opportunity though: pages that dont show up in Allpages are getting created, and those we could honey trap, any more about which I wont say for obvious reasons. It wont stop people spamming it, but with such page(s) not showing up in Allpages and not getting linked to theyre effectively not visible to readers, plus the spam wont be, so it could saves us significant work.<br />
<br />
I really wish wiki had tickboxes on recent changes for fast mass blocking & deletion. Lack of them makes the job take 10x longer.<br />
<br />
I'll go check the user id list.<br />
[[User:NT|NT]] 13:01, 23 February 2008 (GMT)<br />
<br />
<br />
Last time we protected a few target pages it took quite a number of months for them to find new ones. It might be interesting to unprotect some of those now and see what happens.<br />
<br />
--[[User:John Rumm|John Rumm]] 16:21, 23 February 2008 (GMT)<br />
<br />
== Quiet round here.... ==<br />
<br />
Gosh, a whole week and no spam yet, makes a nice change ;-) --[[User:John Rumm|John Rumm]] 01:04, 17 April 2008 (BST)<br />
<br />
Yep, that was an exceptionally good decision!<br />
[[User:NT|NT]] 10:09, 17 April 2008 (BST)<br />
<br />
== When registered users spam ==<br />
<br />
<br />
It recon we may as well ban them permanently straight off since they obviously created the account for the purpose. <br />
<br />
(I did block ban about 70 a while back where the accounts were all created following a recognisable automated naming pattern - anything not quite readable, 10 characters long. and in camel case seems suspect)<br />
<br />
--[[User:John Rumm|John Rumm]] 15:24, 11 July 2008 (BST)<br />
<br />
<br />
If we do that then why not ban all spammers permamently on the first offence?<br />
[[User:NT|NT]] 01:36, 12 July 2008 (BST)<br />
<br />
Not much point worrying about the IP address ones - just protect the article and ban them for a month in case they are still in a mood for mischief (probably not since most are probably bots on malware infested PCs). That way they can't do any further damage to that page. <br />
<br />
The spam usernames however have the capacity to do far more damage, and we know will never be used for anything worthwhile, so we may as well bin them straight off. There are more hoops to jump through for the spammers to keep creating new users.<br />
<br />
--[[User:John Rumm|John Rumm]] 05:13, 12 July 2008 (BST)<br />
<br />
<br />
Good point, will do that then.<br />
[[User:NT|NT]] 13:38, 12 July 2008 (BST)<br />
<br />
== Rdirect pages ==<br />
<br />
<br />
You deleted the Putties and Mastics page on the grounds of it being a spam threat. I specifically put it there to counter one!<br />
<br />
It had been created a number of times by a spammer. The first time I deleted it they just put it back, so leaving it there with useful content and protecting it prevented further fiddling with it. Hence why I sometimes set a spammed new page to something like "page intentionally left blank..." and then protect it. <br />
--[[User:John Rumm|John Rumm]] 00:18, 11 January 2009 (GMT)<br />
<br />
<br />
Sounds like a misunderstanding, I know why it was there. I deleted it because the spammer was no longer creating any pointless new pages, hence it was no longer needed. Maybe I was a little hasty and should have asked first: do you think we still need it?<br />
[[User:NT|NT]] 08:52, 11 January 2009 (GMT)<br />
<br />
I guess we will find out in time ;-)<br />
<br />
As a general rule, having redirect pages that get you to appropriate topics from slight variations in search term are not a bad thing IMHO.<br />
<br />
(I presume the spammer used that topic in the hope that it would be missed since it looked like an edit to a genuine article). (although why spammers bother with mediawiki anywany I don't know since it has the nofollow attribute automatically generated for all pages anyway!)<br />
<br />
--[[User:John Rumm|John Rumm]] 13:37, 11 January 2009 (GMT)<br />
<br />
We could consider making the need for an account the default for creating new articles... or possibly blocking anonymous edits altogether. (I have the FTP log on details for the wiki server, so we can tweak config files if we need to). --[[User:John Rumm|John Rumm]] 13:42, 11 January 2009 (GMT)<br />
<br />
<br />
Well I'm all for that! Would wipe out a percentage of the little remaining spam.<br />
[[User:NT|NT]] 16:14, 11 January 2009 (GMT)<br />
<br />
An interesting read (sorry to butt in on your conversation!). It sounds like this battle against the spammers has been on-going here for quite some time.<br />
<br />
Out of interest, have you considered using a [http://en.wikipedia.org/wiki/Captcha Captcha] which could be required for account creation, & also subsequently required every time before a page could be edited/created? It wouldn't stop the human spammers, but all but the most sophisticated spambots might have a hard time getting in here after that. Or perhaps this site is built upon a fixed template, which Admin is unable to alter?<br />
<br />
- Ax<br />
<br />
<br />
We did discuss captcha, but this specific version of wiki software doesn't support it. For the most part we've stopped the spam by changing the default permissions on pages. Most days there's no spam now, its not perfect though.<br />
<br />
I think we could do with a specific spam discussion page!<br />
14:09, 15 April 2009 (BST)<br />
<br />
== Looks like the dickheads are out in force... ==<br />
<br />
I was toying with the idea of blocking creation of accounts by non sysops for a bit. I.e. if you want an account you post a request to an article with a request and one of us picks it up and creates the account... (or not!) <br />
<br />
I have got a fix in the config file to try it out - but it does not seem to be doing its stuff. It might be we need to restart mediawiki for it to see the change though. I will have a word with Grunff and see.<br />
<br />
--[[User:John Rumm|John Rumm]] 05:47, 23 April 2009 (BST)<br />
<br />
We sure need to do something! I don't really know enough about mediawiki to offer any ideas unfortunately. The ability to mass block accounts would be a blessing.<br />
[[User:NT|NT]] 11:32, 23 April 2009 (BST)<br />
<br />
OK, I have knobbled new account creation ;-) <br />
<br />
There is a new article here: [[Account Requests]] that punters can add to if they want an account (obviously we will have to leave this open for anonymous edits). If the spammers pick up on that, then we can create a gmail account for the purpose. <br />
<br />
I suggest adding the account requests article to your watch list, then then if you see an entry and it looks genuine, email the requester as a test asking for a password, and when they reply, create the account and email them to say its done. <br />
<br />
--[[User:John Rumm|John Rumm]] 23:06, 23 April 2009 (BST)<br />
<br />
== Quiet in here today innit! ==<br />
<br />
<br />
For a while at least!<br />
<br />
--[[User:John Rumm|John Rumm]] 23:43, 24 April 2009 (BST)<br />
<br />
Grin :)<br />
<br />
I just hope it wont stop genuine contributions.<br />
[[User:NT|NT]] 00:13, 25 April 2009 (BST)<br />
<br />
== I just knobbled anonymous creation of pages... ==<br />
<br />
See what the spammers think of that ;-)<br />
<br />
--[[User:John Rumm|John Rumm]] 14:52, 19 May 2009 (BST)<br />
<br />
Ah good! nice one<br />
[[User:NT|NT]] 23:59, 19 May 2009 (BST)<br />
<br />
<br />
If this carries on, I can knobble all anonymous editing...<br />
--[[User:John Rumm|John Rumm]] 23:51, 15 April 2010 (BST)<br />
<br />
Sounds like a sensible policy tbh. I know its nice to allow it for the potential contributions, but all it ever brought before us was a mountain of spam<br />
[[User:NT|NT]] 23:59, 15 April 2010 (BST)<br />
<br />
== Protection ==<br />
<br />
You know I could knobble all anonymouse edits if you want. Then we would need to explicitly enable rights for a page to be edited by non account holders.<br />
<br />
--[[User:John Rumm|John Rumm]] 16:15, 21 August 2010 (BST)<br />
<br />
I'm wondering why that wasn't done before now. We seldom get anonymous contributions, just endless spam.<br />
[[User:NT|NT]] 08:45, 23 August 2010 (BST)<br />
<br />
== Wave goodbye to the spam ==<br />
<br />
ok I have blocked anonymous edits across the whole wiki. You can only post now when logged in. One side effect of this is that I have had to change the account creation procedure since there is not currently a way to override the default permission level on a per article basis. I may be able to install and extension to make this possible though later. <br />
<br />
--[[User:John Rumm|John Rumm]] 04:25, 10 September 2010 (BST)<br />
<br />
Phew. Though I hadn't thought about that issue. Maybe I'll put a note temporarily on the new accounts page.<br />
[[User:NT|NT]] 08:23, 10 September 2010 (BST)<br />
<br />
Already changed the instructions to say email or post to the group for an account. <br />
--[[User:John Rumm|John Rumm]] 18:01, 11 September 2010 (BST)<br />
<br />
Yes, I soon saw :)<br />
[[User:NT|NT]] 22:49, 12 September 2010 (BST)<br />
<br />
== Latest ==<br />
<br />
Latest has been mainly:<br />
* adding new pics<br />
* replacing pics with better ones<br />
* adding articles to existing categories<br />
* also a few article tidy-ups<br />
<br />
== Today ==<br />
<br />
Sorted out lots of article titles for linkability. No doubt a few links not yet sorted as a result, but they should get done sooner or later. If finished it'll make article writing easier & quicker.<br />
[[User:NT|NT]] 01:05, 9 December 2010 (UTC)<br />
<br />
== Boiler/Boilers etc ==<br />
Just replied on my talk page [[User:John Stumbles|YAPH]] 22:39, 7 February 2011 (UTC)</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=User_talk:John_Stumbles&diff=14761User talk:John Stumbles2011-02-07T22:37:16Z<p>John Stumbles: /* Article names */</p>
<hr />
<div>Talk to me here! [[User:John Stumbles|John Stumbles]]<br />
----<br />
Hi John<br />
<br />
I came across your excellent articles while researching a shower problem via various sites, and I'm hoping that perhaps you can help.<br />
<br />
My son has recently moved into a new (to him, IYSWIM) house. The house has been renovated by the previous owners and has a combi boiler. The problem is with the shower in the bathroom which is a "Victorian" style (i.e.brass & porcelain) and which although apparently "thermostatic" does not control the water temperature at all. The temperature varies randomly, but always too hot for comfort, no matter what the control setting is. I should mention that the control is a single lever for both flow and temperature.<br />
<br />
The markings on the shower mixer valve indicate that it is a "Force 10 Thermostatic". I am unsure if this is the name of the manufacturer, or the model. I cannot find any references to this name on t'internet at all.<br />
<br />
I have dismantled the valve, and tested the thermostat capsule in a bowl of hot water and it appears to operate OK.<br />
<br />
Have you come across "Force 10" before? Any ideas what to do next?<br />
<br />
TIA<br />
<br />
Peter Kay<br />
<br />
: Peter: I suggest you ask this on the newsgroup as you will get responses from people with a wider range of expertise and experience than just mine --[[User:John Stumbles|John Stumbles]] 11:18, 31 July 2007 (BST)<br />
<br />
Thanks John. I've posted a couple of times but nobody has come up with the answer yet! Thanks again.<br />
<br />
<br />
<br />
This has been discussed on the group before. AIUI a standard combi and standard thermostatic shower are incompatible. If you think about how the thermostatic shower controls temp, and how this affects a combi you should see why. The ng is the place tho.<br />
[[User:NT|NT]] 00:09, 1 August 2007 (BST)<br />
<br />
== DIY Heatbank ==<br />
<br />
Hi John<br />
Great easy to follow articles.<br />
Re the DIY heatbank, would you now suggest any modifications to the original? I'd particularly be interested in how best to link 2 100L standard direct cylinders together to form one store.<br />
Ian<br />
<br />
I've no experience of such an arrangement so I'd suggest discussing it in the diy newsgroup. --[[User:John Stumbles|John Stumbles]] 21:45, 20 November 2007 (GMT)<br />
<br />
== Done a picture upgrade... ==<br />
<br />
See [[Motorised_Valves]]. I added a link to the fill zoning article as well since that now has a nice diagrams for all the various plans along with detailed wiring centre schematics etc. <br />
<br />
--[[User:John Rumm|John Rumm]] 17:36, 26 August 2009 (BST)<br />
<br />
== SENTINEL X100 INHIBITOR ==<br />
<br />
Hi John<br />
<br />
I read with interest your test on inhibitors. We are currently investigation Sentinel X100 which appears to have altered it's dosing rate by 30%. Do you have any records dating back to 2004 when you carried out the test? Do you have the original paperwork showing the dosing rate at 100 to 1? <br />
<br />
Thanks<br />
<br />
Harvey Bowden (Harvey Water Softeners Ltd. www.harvey.co.uk,<br />
<br />
== Article names ==<br />
<br />
Hi John. Thought I'd best let you know why what's been done was done.<br />
<br />
Its standard practice in wikis to use article names that avoid plurals and capitalisation other than at the first letter. The reason is that its then simple to make links within the wiki, enabling readers to navigate around easily. Without this, linking is a slow process, and links are often broken, and often just not included.<br />
<br />
When an article is renamed from eg boilers to boiler, the wiki automatically creates a redirect to boiler under the heading boilers, so linking should never be broken. Wiki does this redirect seamlessly, so any link to boilers would go straight to boiler.<br />
[[User:NT|NT]] 13:30, 7 February 2011 (UTC)<br />
<br />
----<br />
<br />
The reason I noticed the Boilers article had been moved was because a link to it from an external website (mine!) had broken. The wiki had not created a redirect from the 'old' URL. This violates the sensible recommendation expounded by Tim Berners-Lee of the W3C "[http://www.w3.org/Provider/Style/URI Cool URIs don't change]"!<br />
<br />
Nor had the wiki automatically created redirects or changed links within itself, so after you'd changed the capitalisation of some article names my brag list on my user page had several red links.<br />
<br />
If you want to create ''new'' stubs that redirect to article names with the capitalisation and singularisation you prefer that's fine by me, but I feel strongly that we should keep the originals in place so that existing links - internal and from outside - continue to work. <br />
<br />
I think it's a bit like uk.d-i-y itself: we're in the 'wrong' place in the heirarchy - we should be at somewhere like uk.rec.d-i-y - but I think everyone agrees it would be wrong for all sorts of reasons to try to move the group since it is established where it is.<br />
<br />
[[User:John Stumbles|YAPH]] 22:37, 7 February 2011 (UTC)</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Underfloor_Heating&diff=14758Underfloor Heating2011-02-07T01:13:58Z<p>John Stumbles: Change John Guest UFH page URL</p>
<hr />
<div>''See the [[Central_Heating_Design#Underfloor|Central Heating Design article]] for pros and cons of underfloor heating compared to radiators etc.''<br />
<br />
The use of warmed floors to heat spaces goes back at least to the Romans who used [http://en.wikipedia.org/wiki/Hypocaust hypocausts] to heat buildings using wood as fuel. Modern Underfloor Heating systems ("'''UFH'''") can be [[Central Heating Design|designed]] and installed as part of a wet hydronic [[central heating]] system or can be separate Electrically heated areas.<br />
<br />
The following regards wet CH-based systems:<br />
<br />
== Suppliers ==<br />
<br />
=== Uponor ===<br />
<br />
[http://www.uponorhousingsolutions.co.uk/ Uponor] (formerly '''Wirsbo''') are long-established suppliers of UFH. <br />
<br />
{| style="width:85%" border="1" cellpadding="2"<br />
|-<br />
| Their web site's pages carry the now-common indication of the path through the document tree to the current page e.g. <br />
: Products > Underfloor Heating > PEX 15 Pipe<br />
but you can't always get further along the path from a given page! Instead you have to use the pop-up menus from the navigation bar on the left of the page.<br />
|}<br />
<br />
Requires (free) registration for <br />
[http://www.uponorhousingsolutions.co.uk/RegUsers/downloads.aspx PDF datasheet downloads] including:<br />
* [http://www.uponorhousingsolutions.co.uk/Downloads/Installation%20Guide%20for%20Domstic%20UFH%202006.pdf illustrated design & installation guide]<br />
* [http://www.uponorhousingsolutions.co.uk/Downloads/wirsbo%2020%20design%20guide%20may%202004.pdf Design guide]<br />
* [http://www.uponorhousingsolutions.co.uk/Downloads/Kanmor%20360e%20Weather%20Compensator.pdf weather compensator]<br />
<br />
Uponor supports installation in screeded solid floors, suspended floors with spreader plates or with their proprietary system using metallised bubble-wrap backing, and floating floors with 50mm panels.<br />
<br />
=== Continental===<br />
[http://www.continental-ufh.com Continental] are a significant established supplier of UFH in the UK.<br />
<br />
Their wesbite details the range of products which includes multi-layer AluPEX pipes and 5-layer PEX pipes. Their founder (Chris Ingram) is Chairman of the Technical Committee of the UK trade associaition, [http://www.uhma.info UHMA].<br />
<br />
Downloads available include:<br />
* [http://www.continental-ufh.com/download/CUFH_quote_form_web_r311007.pdf Free quote form]<br />
* [http://www.continental-ufh.com/download/CUFH_bro07_web_download_r311007.pdf Brochure]<br />
<br />
Latest industry [http://www.continental-ufh.com/news.asp news] and advice on [http://www.continental-ufh.com/floorcovering.asp floor coverings] is available<br />
<br />
Continental systems support installation in screeded floors, fit from above or below systems for timber joists, suspended floors and floating floors.<br />
<br />
<br />
=== Hepworth ===<br />
[http://www.hep2o.co.uk/quotes.htm Hepworth] (formerly '''Bartol''') are another long-established supplier of UFH in the UK. <br />
<br />
UFH Guides avalable as PDFs including:<br />
* [http://www.hep2o.co.uk/ufh/UFHFloorConstruction.pdf floor construction]<br />
* [http://www.hep2o.co.uk/ufh/UFHFloorLayouts.pdf floor layouts]<br />
* [http://www.hep2o.co.uk/ufh/TrainingGuide.pdf training guide] 'benefits' and installation practise<br />
* [http://www.hep2o.co.uk/ufh/UFHConservatoryPack.pdf conservatory pack] simple packaged kit for single solid-floored rooms using flow-limiting temperature valve in return circuit<br />
Supports solid, suspended and floating floors.<br />
<br />
=== Polypipe ===<br />
<br />
[http://www.polypipe.com/polypipe/products/building-products/ufch Polypipe UFH systems] (widely available in DIY outlets e.g. B&Q)<br />
* [http://www.ufch.com/ Trade site]<br />
** [http://www.ufch.com/Downloads/02-dandi-guide.pdf Design and Installation Guide] [PDF]<br />
* [http://www.freeyourwalls.com/ Consumer site]<br />
<br />
Floor types supported include [http://www.polypipe.com/polypipe/controller?action=BP-Products&categoryID=283 overlay] 18mm thick using 12mm pipe.<br />
<br />
<br />
=== John Guest ===<br />
<br />
(Makers of '''Speedfit'''). <br />
<br />
Their [http://www.speedfitufh.co.uk/ UFH web page] gives a comprehensive guide to:<br />
* basics of UFH<br />
* solid floor construction<br />
* design principles<br />
* controls<br />
* heatloss (with R values for different surface finishes)<br />
* pipe layout<br />
* output tables<br />
* installation practise<br />
<br />
=== Nu-Heat ===<br />
Nu-Heat supplies integrated underfloor heating, heat pump and solar solutions. With over 60 floor constructions the underflor heating can be incorporated into screed, floating and suspended timber floors.<br />
<br />
- [http://www.nu-heat.co.uk/s.nl/sc.7/category.18/.f Floor coverings]<br />
<br />
- [http://www.nu-heat.co.uk/s.nl/it.I/id.172/.f?sc=7&category=40 UFH Design Process]<br />
<br />
http://www.nu-heat.co.uk/<br />
<br />
Warm water underfloor heating works by pumping a controlled flow of warm water from any heat source through plastic tubing embedded in the floor. Because the emitting area is large, sufficient warmth is provided even on a cold winter day with no need for supplementary heating.<br />
<br />
=== Osma ===<br />
<br />
http://www.osmaufh.co.uk/<br />
<br />
=== Rehau ===<br />
<br />
http://www.rehau.co.uk/building.solutions/underfloor.heating/floor.systems/floor.systems.shtml<br />
<br />
=== Royalle ===<br />
<br />
Supply a range of typical UFH systems but also make a thin (15mm or 25mm finished) screeded system based on zinc-plated steel honeycomb which, it is claimed, can be laid over existing wooden floors, even those in poor condition. The system is also claimed to have relatively short warm-up and cool-down times.<br />
<br />
* [http://www.royalle.co.uk Royalle web site]<br />
* [http://www.royalle.co.uk/max4therm_underfloor.html Max4therm thin system]<br />
<br />
=== Floorheater ===<br />
<br />
System comprising thin "poly" panels grooved for PEX pipe with bonded foil heat diffuser. Panels can be cut with a craft-knife, and glued, screwed or nailed onto surface.<br />
<br />
Also available in thicker "Easy Panel" incorporating insulation.<br />
<br />
* [http://www.floorheater.co.uk/ Floorheater web site]<br />
<br />
[[Category:Plumbing]]<br />
[[Category:Heating]]<br />
[[Category:Floors]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=User:John_Stumbles&diff=14757User:John Stumbles2011-02-06T22:16:43Z<p>John Stumbles: Changed link to YAPH Gas Safe page</p>
<hr />
<div>I am a practicing [http://yaph.co.uk/ plumbing & heating engineer]. I do mostly domestic work - anything from changing a tap washer to installing a central heating system or bathroom (although I mostly concentrate on the smaller jobs). I live and work in Reading.<br />
<br />
For most of my career I worked in electronics, computer networking and lately hardware/software testing. I have always been a DIY-er, from messing around with electrics (including mains!) as a child, through to renewing the plumbing, electrics etc on the first house I bought in 1978. When I was made redundant from my IT job in 2002 I started doing small plumbing, electrical and general house maintenance jobs for friends and neighbours. I did a short training course at the local Technical College to acquire my NVQ in plumbing (actually called "Domestic Heating") which allowed me to enrol on their training for, and take, my ACS and become CORGI (now [http://yaph.co.uk/GasSafe Gas Safe]) registered. <br />
<br />
I am still interested in IT and have moved over to running Linux on all my home PCs, which are now entirely Microsoft-free. I maintain a [http://yaph.org.uk/ small web site of computer how-tos and suchlike].<br />
<br />
As a professional I am just as keen to share my knowledge with others through the uk.d-i-y newsgroup as I was when I was a pure DIYer. There is a great range of expertise amongst contributors to the group, including many other professionals in areas which are also the subject of DIY activities such as plumbing, heating, electrics, structural engineering, various building practices etc. And where I do have knowledge to contribute to a query or discussion the process of understanding a problem and attempting to explain my understanding of it is a good way of practicing the analytical and communication skills I need in my job!<br />
<br />
I am particularly keen in on wikis: I suppose that, as essentially DIY websites, they tickle my fancy for both DIY and IT! I am also a contributor to [http://en.wikipedia.org/wiki/User:John_Stumbles Wikipedia] and [http://tools.wikimedia.de/~daniel/WikiSense/Gallery.php?wikifam=commons.wikimedia.org&img_user_text=John_Stumbles Wikimedia Commons]. You can find my personal website [http://stumbles.org.uk/ here].<br />
<br />
In this wiki I have concentrated mainly on what I know something about: [[:category:plumbing|plumbing]] and [[:category:heating|heating]]. In my professional capacity I find that some of my clients are interested in how their plumbing and heating systems work and/or what choices are available for them in extending or replacing them etc., so I hope that the articles I write and contribute to here may be useful to them. I sometimes work alongside clients who DIY parts of jobs for themselves, for example installing a boiler for a client who is installing other parts of a CH system for themselves.<br />
<br />
I am particularly interested in energy conservation and efficiency as I consider that climate change is a real threat to our planet. (Whether or not it is a result of human activities - as has been the subject of discussion recently - it seems prudent to treat it as if it is, and in any case worthwhile to try to influence it for our benefit by our own actions.)<br />
<br />
You can leave messages for me on [[User_talk:John_Stumbles|my talk (discussion) page]]. If you have registered an account on this wiki then you can '''watch''' the page for my reply. (You also get your own [[User:Jo Bloggs|user page]].)<br />
<br />
<br />
----<br />
==Brag List==<br />
<br />
Here are some articles I've originated and/or done a fair amount of work on:<br />
<br />
* [[Plumbing]]<br />
* [[Central Heating]]<br />
** [[Central Heating Design]]<br />
*** [[Underfloor Heating]]<br />
*** [[Central Heating Radiators]]<br />
*** [[Central Heating Controls and Zoning]]<br />
**** [[Motorised Valves]]<br />
** [[Central Heating Operation]]<br />
*** [[Corrosion Inhibitor]]<br />
** [[Central Heating Repair]]<br />
** [[Fitting TRVs to Microbore]]<br />
* [[Boilers]]<br />
** [[Boiler Evolution]]<br />
** [[Combination Boilers]]<br />
* [[Domestic Hot Water]]<br />
* [[Domestic Hot Water Systems]]<br />
** [[Unvented DHW]]<br />
** [[Thermal Stores and Heat Banks]]<br />
*** [[DIY Heat Bank]]<br />
* [[Showers]]<br />
** [[Installing a Bar-type Shower Mixer Valve]]<br />
* [[3-dimensional pipe bending]]<br />
<br />
* [[Regulations]]<br />
<br />
* [[Electricity]]<br />
* [[Earthing and Bonding]] (from text by [[User:John Rumm|John Rumm]])<br />
<br />
Related to this Wiki itself<br />
* [[Main Page]]<br />
* [[Creating and Editing Articles]]<br />
* [[Example article]]<br />
* [[:Template:Accidental-deletion-warning]]<br />
* [[:Template:Under-construction]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Central_Heating_operation&diff=14756Central Heating operation2011-02-06T22:14:44Z<p>John Stumbles: Central Heating operation moved to Central Heating Operation: Oops - correct change back to original version</p>
<hr />
<div>#REDIRECT [[Central Heating Operation]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Central_Heating_Operation&diff=14755Central Heating Operation2011-02-06T22:14:44Z<p>John Stumbles: Central Heating operation moved to Central Heating Operation: Oops - correct change back to original version</p>
<hr />
<div>This article is about operating [[Central heating]] systems using hot water fed radiators. It assumes the system is functional.<br />
<br />
There are also articles about:<br />
* [[Central Heating Design]] which may help understanding what sort of system you have.<br />
* [[Central Heating Repair]] for help diagnosing and fixing a faulty system<br />
* Other heating topics are found by clicking the heating category link at the bottom.<br />
<br />
<br />
Fanned warm-air ducted systems are occasionally found in the UK. These operate quite differently and their use is not covered here. (There is a discussion on updating existing warm-air systems [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/cd973db3a3604624? here])<br />
<br />
<br />
==Time & temperature controls==<br />
* Programmer and room thermostat<br />
** check there is a room stat<br />
** check no other sources of heat or valves turned down in stat area<br />
* Programmable thermostat<br />
** fully programmable or set-back<br />
** optimum start (Honeywell issue)<br />
* combis with pre-heat<br />
<br />
===Setting boiler temperature control===<br />
As well as a room thermostat, there is also a thermostat on the boiler itself. This thermostat adjusts the temperature of the circulating heating water.<br />
<br />
The lower the temp of this water, the more efficient the boiler operates, but the lower is the system heat output. If a heating system is failing to keep the house warm enough, turning this thermostat up often resolves the problem. In milder weather it can be turned down to improve efficiency.<br />
<br />
Some systems experience kettling when this thermostat is adjusted too high. Kettling is water boiling in the boiler exchanger when the pump stops. It sounds like banging and thumping, and can prematurely damage some boilers.<br />
<br />
<br />
===Run 24/7 or turn up and down===<br />
Total energy use is always less when the system is turned down when not needed. At any moment, rate of heat loss is proportional to the temperature difference between the house interior and outdoors, so total heat loss is reduced when house temp is reduced when heat ins't needed.<br />
<br />
===Frost protection when house empty===<br />
Set the room thermostat to minimum or 5 degrees C. <br />
<br />
Switching the system fully off instead can sometimes result in water or heating pipes freezing and bursting, potentially causing thousands of pounds of damage.<br />
<br />
<br />
==Radiator controls==<br />
===Setting Thermostatic Radiator Valves (TRVs)===<br />
If there is a TRV on the radiators in the room with the room thermostat, these TRVs should be set to max temp setting.<br />
<br />
Radiators in other rooms that have TRVs should have their lockshield (manual) valves set full on, and the TRV adjusted to give the desired room temp.<br />
<br />
===Setting manual radiator valves===<br />
Check the valves on the radiators in the room with the room thermostat are fully open. To turn these valves full, screwing the caps anticlockwise. The temperature in this room is now controlled by the room stat rather than the rad valve.<br />
<br />
Adjust rad valves in other rooms to achieve even temperature through the house. With some houses the room temps take a day to stabilise. Little used rooms will generally be adjusted to provide a lower room temperature.<br />
<br />
With a new or very maladjusted system, all valves fully open is a good place to start from.<br />
<br />
<br />
==User maintenance==<br />
===Balancing radiators===<br />
Radiators are balanced by adjusting the manual lockshield valves or TRVs. See the Radiator controls section above.<br />
<br />
<br />
===Bleeding a CH system===<br />
Bleeding radiators is needed when some of the radiator is hot, but the top is not. This problem is caused by air buildup in the radiators, which is caused by <br />
* corrosion<br />
* sucking in air from the header tank<br />
* or pumping over in the header tank, which oxygenates the water<br />
<br />
To bleed a radiator, loosen the little bleed screw at one end of the top of the radiator using a radiator key or pliers. Air will escape with a hiss, when the hissing stops and just water comes out, retighten the screw. Dribbles can be anything from clean water to black, so have a towel ready to catch a little spillage.<br />
<br />
The need to bleed any more than very occasionally indicates some sort of problem. Topping up the system corrosion inhibitor solves this in a lot of cases.<br />
<br />
===Topping up a sealed system===<br />
* why? check for how pressure being lost<br />
<br />
===Setting a system bypass===<br />
<br />
==See Also==<br />
* [[Central Heating Design]]<br />
* [[Central Heating Repair]]<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
<br />
<br />
<br />
[[Category:Plumbing]]<br />
[[Category:Heating]]<br />
[[Category:Energy Efficiency]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Central_heating_operation&diff=14754Central heating operation2011-02-06T22:14:01Z<p>John Stumbles: Central heating operation moved to Central Heating operation: Changed name back to original capitalised version since change broke links elsewhere</p>
<hr />
<div>#REDIRECT [[Central Heating operation]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Central_Heating_Operation&diff=14753Central Heating Operation2011-02-06T22:14:00Z<p>John Stumbles: Central heating operation moved to Central Heating operation: Changed name back to original capitalised version since change broke links elsewhere</p>
<hr />
<div>This article is about operating [[Central heating]] systems using hot water fed radiators. It assumes the system is functional.<br />
<br />
There are also articles about:<br />
* [[Central Heating Design]] which may help understanding what sort of system you have.<br />
* [[Central Heating Repair]] for help diagnosing and fixing a faulty system<br />
* Other heating topics are found by clicking the heating category link at the bottom.<br />
<br />
<br />
Fanned warm-air ducted systems are occasionally found in the UK. These operate quite differently and their use is not covered here. (There is a discussion on updating existing warm-air systems [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/cd973db3a3604624? here])<br />
<br />
<br />
==Time & temperature controls==<br />
* Programmer and room thermostat<br />
** check there is a room stat<br />
** check no other sources of heat or valves turned down in stat area<br />
* Programmable thermostat<br />
** fully programmable or set-back<br />
** optimum start (Honeywell issue)<br />
* combis with pre-heat<br />
<br />
===Setting boiler temperature control===<br />
As well as a room thermostat, there is also a thermostat on the boiler itself. This thermostat adjusts the temperature of the circulating heating water.<br />
<br />
The lower the temp of this water, the more efficient the boiler operates, but the lower is the system heat output. If a heating system is failing to keep the house warm enough, turning this thermostat up often resolves the problem. In milder weather it can be turned down to improve efficiency.<br />
<br />
Some systems experience kettling when this thermostat is adjusted too high. Kettling is water boiling in the boiler exchanger when the pump stops. It sounds like banging and thumping, and can prematurely damage some boilers.<br />
<br />
<br />
===Run 24/7 or turn up and down===<br />
Total energy use is always less when the system is turned down when not needed. At any moment, rate of heat loss is proportional to the temperature difference between the house interior and outdoors, so total heat loss is reduced when house temp is reduced when heat ins't needed.<br />
<br />
===Frost protection when house empty===<br />
Set the room thermostat to minimum or 5 degrees C. <br />
<br />
Switching the system fully off instead can sometimes result in water or heating pipes freezing and bursting, potentially causing thousands of pounds of damage.<br />
<br />
<br />
==Radiator controls==<br />
===Setting Thermostatic Radiator Valves (TRVs)===<br />
If there is a TRV on the radiators in the room with the room thermostat, these TRVs should be set to max temp setting.<br />
<br />
Radiators in other rooms that have TRVs should have their lockshield (manual) valves set full on, and the TRV adjusted to give the desired room temp.<br />
<br />
===Setting manual radiator valves===<br />
Check the valves on the radiators in the room with the room thermostat are fully open. To turn these valves full, screwing the caps anticlockwise. The temperature in this room is now controlled by the room stat rather than the rad valve.<br />
<br />
Adjust rad valves in other rooms to achieve even temperature through the house. With some houses the room temps take a day to stabilise. Little used rooms will generally be adjusted to provide a lower room temperature.<br />
<br />
With a new or very maladjusted system, all valves fully open is a good place to start from.<br />
<br />
<br />
==User maintenance==<br />
===Balancing radiators===<br />
Radiators are balanced by adjusting the manual lockshield valves or TRVs. See the Radiator controls section above.<br />
<br />
<br />
===Bleeding a CH system===<br />
Bleeding radiators is needed when some of the radiator is hot, but the top is not. This problem is caused by air buildup in the radiators, which is caused by <br />
* corrosion<br />
* sucking in air from the header tank<br />
* or pumping over in the header tank, which oxygenates the water<br />
<br />
To bleed a radiator, loosen the little bleed screw at one end of the top of the radiator using a radiator key or pliers. Air will escape with a hiss, when the hissing stops and just water comes out, retighten the screw. Dribbles can be anything from clean water to black, so have a towel ready to catch a little spillage.<br />
<br />
The need to bleed any more than very occasionally indicates some sort of problem. Topping up the system corrosion inhibitor solves this in a lot of cases.<br />
<br />
===Topping up a sealed system===<br />
* why? check for how pressure being lost<br />
<br />
===Setting a system bypass===<br />
<br />
==See Also==<br />
* [[Central Heating Design]]<br />
* [[Central Heating Repair]]<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
<br />
<br />
<br />
[[Category:Plumbing]]<br />
[[Category:Heating]]<br />
[[Category:Energy Efficiency]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Central_heating&diff=14752Central heating2011-02-06T22:12:31Z<p>John Stumbles: Central heating moved to Central Heating: Moved back to original name (both words capitalised) since name change broke links elsewhere in this wiki!</p>
<hr />
<div>#REDIRECT [[Central Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Central_Heating&diff=14751Central Heating2011-02-06T22:12:31Z<p>John Stumbles: Central heating moved to Central Heating: Moved back to original name (both words capitalised) since name change broke links elsewhere in this wiki!</p>
<hr />
<div>Aspects of Central Heating are covered in separate articles:<br />
* [[Central Heating Design]]: choosing a design for, and installing a new central heating system; and understanding how an existing system is designed<br />
** [[Boiler]]s: short guide to different types of boilers<br />
** [[Central Heating Controls and Zoning]]<br />
* [[Central heating operation]]: maintaining a working CH system<br />
* [[Central Heating Repair]]: diagnosing and fixing a faulty system.<br />
<br />
== See Also ==<br />
*[[:category:heating|All articles in Heating category]]<br />
<br />
==External links==<br />
* [http://content.wavin.com/__C12574CC0048F5D9.nsf/0/6C35923328D92F18C12574CD0036247A/$FILE/THDesignConsiderations.pdf Hep2O Design Considerations] paper from Hepworth covering design and installation of domestic water supply and heating. Much of this paper is applicable to plumbing systems generally, and to plastic pipework systems beside the company's own "Hep2O".<br />
<br />
[[Category:Plumbing]]<br />
[[Category:Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Talk:Boiler&diff=14750Talk:Boiler2011-02-06T22:09:39Z<p>John Stumbles: Talk:Boiler moved to Talk:Boilers: a) original name was 'Boilers' (plural) and there are links to it from external sites which it is discourteous to break.
b) the article is about boilers in general not a boiler in particular</p>
<hr />
<div>#REDIRECT [[Talk:Boilers]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Talk:Boilers&diff=14749Talk:Boilers2011-02-06T22:09:39Z<p>John Stumbles: Talk:Boiler moved to Talk:Boilers: a) original name was 'Boilers' (plural) and there are links to it from external sites which it is discourteous to break.
b) the article is about boilers in general not a boiler in particular</p>
<hr />
<div>==Categories==<br />
Do boilers belong in appliances?<br />
[[User:NT|NT]] 16:03, 24 April 2007 (BST)<br />
<br />
I don't think so. In a commonsense sort of approach I feel they're different: you don't go out and buy a boiler the way you might to a washing machine or fridge. It's more like a Consumer Unit or perhaps a fixed aircon unit. --[[User:John Stumbles|John Stumbles]] 20:44, 24 April 2007 (BST)<br />
<br />
==Condensing boiler chimney flue liner==<br />
This is really just a bookmark. Maybe there'll be an article it can be used in one day :-)<br />
<br />
French manufacturer Poujoulat make a flexible chimney lining kit called Flexcondens.<br />
* http://www.poujoulat.fr/produits_fiche.asp?produit=44&liste_niveau1=&liste_niveau2=&liste_niveau3=&liste_equipements=&liste_besoins=produits_dessin2.asp&retour_liste=ok (in French - their UK website at http://www.poujoulat.co.uk doesn't have this at the time of writing) --[[User:John Stumbles|John Stumbles]] 00:03, 25 April 2008 (BST)<br />
<br />
== Worcester Discontinued gas boilers ==<br />
Found this list on http://www.worcester-bosch.co.uk/installer/literature/discontinued-boiler-literature/discontinued-gas-boiler-literature<br />
<br />
=== 230 series===<br />
* 230 (discontinued December 1997)<br />
=== 240 series ===<br />
* 240 BF (discontinued December 1997)<br />
* 240 OF (discontinued December 1997)<br />
* 240 RSF (discontinued December 1997)<br />
=== 280 series ===<br />
* 280 RSF (discontinued February 1997)<br />
* 350 series<br />
* 350 RSF (discontinued July 1998)<br />
=== Highflow 400 series ===<br />
* Highflow 400 BF (discontinued February 2002)<br />
* Highflow 400 OF (discontinued February 2002)<br />
* Highflow 400 RSF (discontinued February 2002)<br />
=== Greenstar series ===<br />
* Greenstar 25 HE Combi (discontinued August 2003)<br />
* Greenstar 30 HE Combi (discontinued August 2003)<br />
* Greenstar 28 HE System (discontinued August 2003)<br />
* Greenstar 29 HE Conventional (discontinued August 2003)<br />
* Greenstar 40 HE Conventional<br />
* Greenstar 30 HE Plus Combi (discontinued August 2003)<br />
* Greenstar 35 HE Plus Combi (discontinued August 2003)<br />
* Greenstar 40 HE Plus Combi<br />
* Greenstar 25CDi (discontinued April 2007)<br />
* Greenstar 30CDi (04/2005 - 03/2007)<br />
* Greenstar 35CDi (discontinued April 2007)<br />
* Greenstar 40CDi (discontinued April 2007)<br />
* Greenstar Highflow 440 (discontinued October 2008)<br />
=== i series ===<br />
* 24i (discontinued November 2004)<br />
* 28i (discontinued November 2005)<br />
=== Si series ===<br />
* 24Si II (discontinued June 2007)<br />
* 25Si (old model: October 2001 - March 2002)<br />
* 28Si (February 2000 - March 2002)<br />
* 28Si II (discontinued June 2007)<br />
=== i Junior series ===<br />
* 24i Junior RSF (discontinued Aug 2007)<br />
* 28i Junior RSF (discontinued Aug 2007)<br />
=== CDi series ===<br />
* 24CDi BF (discontinued March 2005)<br />
* 24CDi OF (discontinued March 2005)<br />
* 24CDi RSF (discontinued June 2007)<br />
* 26CDi Xtra RSF (discontinued June 2007)<br />
* 28CDi RSF (discontinued June 2007)<br />
* 35CDi (discontinued October 2001)<br />
* 35CDi II RSF (discontinued Aug 2007)<br />
=== CBi series ===<br />
* 14/19 CBi (discontinued December 2006)<br />
* 19/24 CBi (discontinued December 2006)<br />
* 9/14 CBi (discontinued December 2006)<br />
=== SBi series ===<br />
* 15SBi RSF (discontinued January 2007)<br />
* 24SBi RSF (discontinued January 2007)<br />
=== Highflow 400 Electronic series ===<br />
* Highflow 400 Electronic BF (discontinued March 2005)<br />
* Highflow 400 Electronic OF (discontinued March 2005)<br />
* Highflow 400 Electronic RSF (discontinued March 2006)</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Boiler&diff=14748Boiler2011-02-06T22:09:39Z<p>John Stumbles: Boiler moved to Boilers: a) original name was 'Boilers' (plural) and there are links to it from external sites which it is discourteous to break.
b) the article is about boilers in general not a boiler in particular</p>
<hr />
<div>#REDIRECT [[Boilers]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Boilers&diff=14747Boilers2011-02-06T22:09:38Z<p>John Stumbles: Boiler moved to Boilers: a) original name was 'Boilers' (plural) and there are links to it from external sites which it is discourteous to break.
b) the article is about boilers in general not a boiler in particular</p>
<hr />
<div>This article is about '''Boilers''' used for [[Central heating]] and, usually, [[DHW| hot water]]. Such boilers usually use Natural Gas, Oil or LPG as fuels. <br />
<br />
Many people seem to be confused by the words '''Condensing''', '''Combi''', '''System''' and '''Heating''' which are applied to types of boilers.<br />
<br />
== Types of Boiler ==<br />
<br />
=== Condensing ===<br />
<br />
Condensing - also known as ''High Efficiency'' - boilers gain extra heat from the fuel they burn by cooling their exhaust (''flue'') gases so that the steam present in hot flue gas turns to water giving up its ''[http://en.wikipedia.org/wiki/Latent_heat Latent Heat]''. This typically adds about 10% to the boiler's efficiency.<br />
<br />
=== Combi ===<br />
<br />
Combination boilers produce [[Domestic Hot Water]] directly (rather than the boiler heating a cylinder of water as in a conventional system). Since they are usually intended to provide most of the components of a central heating and DHW system in one package they usually contain the components of a sealed system, and often a timer as well.<br />
<br />
=== System ===<br />
<br />
System boilers contain the components (pressure vessel, pressure relief discharge valve, pressure gauge and sometimes filling arrangement) to make a ''Sealed System'' (see Ed Sirett's [http://www.makewrite.demon.co.uk/SealedCH.html Sealed System FAQ]). Combi boilers also usually contain these components, so a System boiler can be regarded as a Combi boiler without the DHW-producing components (and some boilers are exactly so: there are spaces where the DHW components of the Combi version of the boiler would fit). System boilers also tend to include the circulation pump within the boiler.<br />
<br />
=== Heating ===<br />
<br />
A Heating-only (or ''regular'') boiler just heats the ''primary'' water circulating through the radiators and hot water cylinder etc. It does not have the components for a sealed system and may not even contain a pump.<br />
<br />
=== Permutations ===<br />
<br />
A boiler may be:<br />
* condensing and a combi<br />
* condensing and non-combi: i.e. system or heating<br />
* non-condensing and combi<br />
* non-condensing and non-combi: i.e. system or heating<br />
<br />
Current Building [[Regulations]] require that new and replacement boilers must generally be Condensing types. The choice of combi, system or heating is not stipulated.<br />
<br />
== See Also ==<br />
* [[Boiler Evolution]]<br />
* [[Domestic Hot Water Systems]]<br />
* [[Central heating]]<br />
* [http://www.makewrite.demon.co.uk/BoilerChoice.html Ed Sirett's Boiler Choice FAQ]<br />
<br />
[[Category:Heating]]<br />
[[Category:Plumbing]]<br />
[[Category:Energy Efficiency]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14318Motorised Valves2010-12-06T20:54:17Z<p>John Stumbles: /* Spring return valves */</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the valve to the open position until the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring pulls the mechanism (and the motor) back, returning it to its original, closed, position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably ''the'' most common type and make of valve found in domestic CH systems. Note the flushing/override lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|768px|Click for larger image]]<br />
<br />
[http://wiki.diyfaq.org.uk/images/d/d2/YplanSchematic.gif See full-size image]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main [[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-on/motor-off (MOMO) types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring is not compatible with modern spring return 3-port valves; the Flow-share requires CH CALL and SAT and only HW CALL whereas spring-return types require only CH CALL but HW CALL and SAT.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14317Motorised Valves2010-12-06T20:53:19Z<p>John Stumbles: /* 2-port */ typos, clarification</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the valve to the open position until the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring pulls the mechanism (and the motor) back, returning it to its original, closed, position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably ''the'' most common type and make of valve found in domestic CH systems. Note the flushing/override lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|768px|Click for larger image]]<br />
<br />
[http://wiki.diyfaq.org.uk/images/d/d2/YplanSchematic.gif See full-size image]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-on/motor-off (MOMO) types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring is not compatible with modern spring return 3-port valves; the Flow-share requires CH CALL and SAT and only HW CALL whereas spring-return types require only CH CALL but HW CALL and SAT.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14316Motorised Valves2010-12-06T20:51:35Z<p>John Stumbles: /* 2-port */</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the valve to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably ''the'' most common type and make of valve found in domestic CH systems. Note the flushing/override lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|768px|Click for larger image]]<br />
<br />
[http://wiki.diyfaq.org.uk/images/d/d2/YplanSchematic.gif See full-size image]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-on/motor-off (MOMO) types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring is not compatible with modern spring return 3-port valves; the Flow-share requires CH CALL and SAT and only HW CALL whereas spring-return types require only CH CALL but HW CALL and SAT.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14315Motorised Valves2010-12-06T20:50:24Z<p>John Stumbles: /* 3-port */</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably ''the'' most common type and make of valve found in domestic CH systems. Note the flushing/override lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|768px|Click for larger image]]<br />
<br />
[http://wiki.diyfaq.org.uk/images/d/d2/YplanSchematic.gif See full-size image]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-on/motor-off (MOMO) types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring is not compatible with modern spring return 3-port valves; the Flow-share requires CH CALL and SAT and only HW CALL whereas spring-return types require only CH CALL but HW CALL and SAT.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14314Motorised Valves2010-12-06T20:42:02Z<p>John Stumbles: /* Drayton Flow-share (3-port MOMO) - discontinued */ remove bit about wiring being quite complicated when it appeared, add note about how it's different from current arrangement</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably '''the''' most common type and make of valve found in domestic CH systems. Note the flushing lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|768px|Click for larger image]]<br />
<br />
[http://wiki.diyfaq.org.uk/images/d/d2/YplanSchematic.gif See full-size image]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-on/motor-off (MOMO) types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring is not compatible with modern spring return 3-port valves; the Flow-share requires CH CALL and SAT and only HW CALL whereas spring-return types require only CH CALL but HW CALL and SAT.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14313Motorised Valves2010-12-06T20:37:06Z<p>John Stumbles: /* 3-port */ change 'motor-open/motor-close' to 'motor-on/motor-off (MOMO)'</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably '''the''' most common type and make of valve found in domestic CH systems. Note the flushing lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|768px|Click for larger image]]<br />
<br />
[http://wiki.diyfaq.org.uk/images/d/d2/YplanSchematic.gif See full-size image]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-on/motor-off (MOMO) types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring was quite complicated when it first appeared (1970s?) so whilst installation was straight-forward, maintenance was difficult for plumbers with no knowledge of the system. The wiring is not compatible with modern spring return 3-port valves.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14312Motorised Valves2010-12-06T20:18:38Z<p>John Stumbles: /* Spring return valves */ increase size of image and add link to full size .gif</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably '''the''' most common type and make of valve found in domestic CH systems. Note the flushing lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|768px|Click for larger image]]<br />
<br />
[http://wiki.diyfaq.org.uk/images/d/d2/YplanSchematic.gif See full-size image]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-open/motor-close types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring was quite complicated when it first appeared (1970s?) so whilst installation was straight-forward, maintenance was difficult for plumbers with no knowledge of the system. The wiring is not compatible with modern spring return 3-port valves.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Talk:Motorised_Valves&diff=14311Talk:Motorised Valves2010-12-06T20:13:22Z<p>John Stumbles: /* Obsolete Drayton valve */</p>
<hr />
<div>need to add info about<br />
* differences in wiring of spring-return & non-spring valves<br />
* how 3-port mid-position valves work<br />
* pictures<br />
<br />
Re the orange picture, it took me some puzzling to work out what it was, a text label would really help.<br />
[[User:NT|NT]] 08:01, 10 January 2007 (GMT)<br />
<br />
But there _is_ a text label under the picture - ?<br />
<br />
--[[User:John Stumbles|John Stumbles]] 19:15, 10 January 2007 (GMT)<br />
<br />
I think the reference to Hydronic wrt a 3 way valve is a spelling mistake perhaps you mean hydraulic, certainly it doesnt make any technical sense as its the tradename if the Smiths fan assisted plinth heater (a finned coil with axial blower)<br />
<br />
The original Honeywell spring return 3 way valve with mid position was a curiously convoluted solution which has been shrouded in mystery untill the description provided (tkx btw) - personally as a professional engineer i hate it aand regard it as a nasty bodge. But a million homes probably still have this device in their Y plan systems.<br />
<br />
I think it worthwhile to discuss the earlier system where a TRV was installed on the outlet of the HW heating coil to give a praticular DHW temperature.<br />
<br />
As I recall - some 30 years ago - there was no zone valve and I think the pump only came on when CH was demanded and only pumped through the radiators. The HW tank was mounted above the boiler and the heating coil was gravity circulated and had 28mm tubes<br />
<br />
: Good point - that might fit well in this section [[Central_Heating_Controls_and_Zoning#Gravity_DHW:_C-Plan|on C Plan]] systems. IIRC there was a popular valve often used for this with a trade name that I forget - something like silitron valve or something like that? --[[User:John Rumm|John Rumm]] 03:15, 13 October 2010 (BST)<br />
<br />
The controller (similar to the Honeywell st699 but and earlier model?) had a mechanical interlock on the sliders controling CH and HW.<br />
<br />
you could have<br />
<br />
All off<br />
HW on 1x 2x<br />
HW + CH on 1x 2x<br />
<br />
NOT<br />
<br />
CH on by itself<br />
<br />
Come to think of it, I dont remember a HW coil bypass gate valve being fitted (not very kind to the boiler (a potterton 40,000 Btu model) but I dont remeber any operating problems.<br />
<br />
<br />
= Obsolete Drayton valve =<br />
Interesting discovery. I'm curious who is [[User:A_tranter]]?<br />
<br />
I've removed the comparison with the Sunvic electronic MOMO which seems spurious since the Drayton under discussion is not - unlike the modern Sunvic MOMO - a drop-in replacement for the 'standard' Honeywell-etc mid-position valve (the standard type requires CH CALL and HW CALL and SAT, whereas the Drayton seems to want CH CALL and SAT and HW CALL). In this respect, clever as the Drayton may be, the old blue Switchmaster is more compatible with current systems.<br />
<br />
I've also changed the text describing the bullet-point list to be that it's a list of features, not of advantages of this valve over modern designs, since some of the listed points (e.g. the plastic cam) are actually disadvantages! Likewise the claim that the discontinuation of this design was the result of a conspiracy withing the heating controls industry to eliminate longer-lived designs. (I'm not saying that isn't the effect of the move to spring-return valves, but there's no evidence for the conspiracy theory and there's a sort of Occam's Razor rule that where something could be conspiracy or cock-up it's generally the latter!)<br />
<br />
[[User:John Stumbles|YAPH]] 20:13, 6 December 2010 (UTC)</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14310Motorised Valves2010-12-06T20:08:29Z<p>John Stumbles: /* Drayton Flow-share (3-port MOMO) - discontinued */ remove final sentence implying conspiracy to make unreliable valves!</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably '''the''' most common type and make of valve found in domestic CH systems. Note the flushing lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|512px|Click for larger image]]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-open/motor-close types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring was quite complicated when it first appeared (1970s?) so whilst installation was straight-forward, maintenance was difficult for plumbers with no knowledge of the system. The wiring is not compatible with modern spring return 3-port valves.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14309Motorised Valves2010-12-06T20:07:16Z<p>John Stumbles: /* Drayton Flow-share (3-port MOMO) - discontinued */ add point about different pipework arrangement</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably '''the''' most common type and make of valve found in domestic CH systems. Note the flushing lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|512px|Click for larger image]]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-open/motor-close types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring was quite complicated when it first appeared (1970s?) so whilst installation was straight-forward, maintenance was difficult for plumbers with no knowledge of the system. The wiring is not compatible with modern spring return 3-port valves.<br />
* The pipework arrangement is also different from modern valves, with inlet being on one of the short arms of the 'T' and the central leg of the 'T' being the CH out port.<br />
Unfortunately the excellent design was discontinued, possibly because they didn't fail for 15-20 years by which time 'better' valves with shorter lifespans had been invented by the plumbing industry.<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14308Motorised Valves2010-12-06T20:03:16Z<p>John Stumbles: /* Drayton Flow-share (3-port MOMO) - discontinued */ remove metal gearing comparison with Sunvic since, as discussed, the valves aren't equivalent</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably '''the''' most common type and make of valve found in domestic CH systems. Note the flushing lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|512px|Click for larger image]]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-open/motor-close types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal.<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring was quite complicated when it first appeared (1970s?) so whilst installation was straight-forward, maintenance was difficult for plumbers with no knowledge of the system. The wiring is not compatible with modern spring return 3-port valves.<br />
<br />
Unfortunately the excellent design was discontinued, possibly because they didn't fail for 15-20 years by which time 'better' valves with shorter lifespans had been invented by the plumbing industry.<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14307Motorised Valves2010-12-06T20:01:59Z<p>John Stumbles: /* Drayton Flow-share (3-port MOMO) - discontinued */ remove 'better than modern designs' since some listed features are worse!</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably '''the''' most common type and make of valve found in domestic CH systems. Note the flushing lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|512px|Click for larger image]]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-open/motor-close types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design has the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal (the Sunvic MOMO valve has plastic gearing).<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring was quite complicated when it first appeared (1970s?) so whilst installation was straight-forward, maintenance was difficult for plumbers with no knowledge of the system. The wiring is not compatible with modern spring return 3-port valves.<br />
<br />
Unfortunately the excellent design was discontinued, possibly because they didn't fail for 15-20 years by which time 'better' valves with shorter lifespans had been invented by the plumbing industry.<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14306Motorised Valves2010-12-06T20:00:34Z<p>John Stumbles: /* Drayton Flow-share (3-port MOMO) - discontinued */ clarify 'only one wire live' statement</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably '''the''' most common type and make of valve found in domestic CH systems. Note the flushing lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|512px|Click for larger image]]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-open/motor-close types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live at any instant) which drove the valve to each of the 3 positions. <br />
The design is far better than most modern designs with the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal (the Sunvic MOMO valve has plastic gearing).<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring was quite complicated when it first appeared (1970s?) so whilst installation was straight-forward, maintenance was difficult for plumbers with no knowledge of the system. The wiring is not compatible with modern spring return 3-port valves.<br />
<br />
Unfortunately the excellent design was discontinued, possibly because they didn't fail for 15-20 years by which time 'better' valves with shorter lifespans had been invented by the plumbing industry.<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Talk:Motorised_Valves&diff=14305Talk:Motorised Valves2010-12-06T19:57:16Z<p>John Stumbles: section about the obsoltere Drayton valve</p>
<hr />
<div>need to add info about<br />
* differences in wiring of spring-return & non-spring valves<br />
* how 3-port mid-position valves work<br />
* pictures<br />
<br />
Re the orange picture, it took me some puzzling to work out what it was, a text label would really help.<br />
[[User:NT|NT]] 08:01, 10 January 2007 (GMT)<br />
<br />
But there _is_ a text label under the picture - ?<br />
<br />
--[[User:John Stumbles|John Stumbles]] 19:15, 10 January 2007 (GMT)<br />
<br />
I think the reference to Hydronic wrt a 3 way valve is a spelling mistake perhaps you mean hydraulic, certainly it doesnt make any technical sense as its the tradename if the Smiths fan assisted plinth heater (a finned coil with axial blower)<br />
<br />
The original Honeywell spring return 3 way valve with mid position was a curiously convoluted solution which has been shrouded in mystery untill the description provided (tkx btw) - personally as a professional engineer i hate it aand regard it as a nasty bodge. But a million homes probably still have this device in their Y plan systems.<br />
<br />
I think it worthwhile to discuss the earlier system where a TRV was installed on the outlet of the HW heating coil to give a praticular DHW temperature.<br />
<br />
As I recall - some 30 years ago - there was no zone valve and I think the pump only came on when CH was demanded and only pumped through the radiators. The HW tank was mounted above the boiler and the heating coil was gravity circulated and had 28mm tubes<br />
<br />
: Good point - that might fit well in this section [[Central_Heating_Controls_and_Zoning#Gravity_DHW:_C-Plan|on C Plan]] systems. IIRC there was a popular valve often used for this with a trade name that I forget - something like silitron valve or something like that? --[[User:John Rumm|John Rumm]] 03:15, 13 October 2010 (BST)<br />
<br />
The controller (similar to the Honeywell st699 but and earlier model?) had a mechanical interlock on the sliders controling CH and HW.<br />
<br />
you could have<br />
<br />
All off<br />
HW on 1x 2x<br />
HW + CH on 1x 2x<br />
<br />
NOT<br />
<br />
CH on by itself<br />
<br />
Come to think of it, I dont remember a HW coil bypass gate valve being fitted (not very kind to the boiler (a potterton 40,000 Btu model) but I dont remeber any operating problems.<br />
<br />
<br />
= Obsolete Drayton valve =<br />
Interesting discovery. I'm curious who is [[User:A_tranter]]?<br />
<br />
I've removed the comparison with the Sunvic electronic MOMO which seems spurious since the Drayton under discussion is not - unlike the modern Sunvic MOMO - a drop-in replacement for the 'standard' Honeywell-etc mid-position valve (the standard type requires CH CALL and HW CALL and SAT, whereas the Drayton seems to want CH CALL and SAT and HW CALL). In this respect, clever as the Drayton may be, the old blue Switchmaster is more compatible with current systems.</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14304Motorised Valves2010-12-06T19:49:59Z<p>John Stumbles: /* Drayton Flow-share (3-port MOMO) - discontinued */ remove comparison with Sunvic MOMO</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably '''the''' most common type and make of valve found in domestic CH systems. Note the flushing lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|512px|Click for larger image]]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-open/motor-close types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live) which drove the valve to each of the 3 positions. <br />
The design is far better than most modern designs with the following features:<br />
* Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal (the Sunvic MOMO valve has plastic gearing).<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring was quite complicated when it first appeared (1970s?) so whilst installation was straight-forward, maintenance was difficult for plumbers with no knowledge of the system. The wiring is not compatible with modern spring return 3-port valves.<br />
<br />
Unfortunately the excellent design was discontinued, possibly because they didn't fail for 15-20 years by which time 'better' valves with shorter lifespans had been invented by the plumbing industry.<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Motorised_Valves&diff=14303Motorised Valves2010-12-06T19:38:24Z<p>John Stumbles: link to 'this author' (of this section)</p>
<hr />
<div>This article is about motorised valves used in [[Central Heating]] systems. Motorised valves are a type of electrically actuated valve (others include solenoid valves and valves using electrically-generated thermal effects).<br />
<br />
Motorised valves generally comprise:<br />
* a synchronous electric motor<br />
* gears to reduce the speed and increase the torque output of the motor<br />
''The motor and gears are often combined in a package known as a '''Synchron''' motor.''<br />
* a linkage from the output gear to the [http://en.wiktionary.org/wiki/hydronic hydronic] part of the valve<br />
* one or more switches (usually [http://en.wikipedia.org/wiki/Microswitch microswitches]) actuated by, for example, a cam attached to the output linkage<br />
* a spring: see below<br />
: the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.<br />
* a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.<br />
<br />
== Configurations of motorised valve ==<br />
Valves are commonly found in the following configurations:<br />
<br />
=== 2-port ===<br />
The valve has 2 pipe connections ('''ports''') and permits or blocks flow between the ports depending on whether it is actuated or not. Flow is permitted when the valve is actuated and blocked in its resting state.<br />
<br />
When the valve is energised a synchronous motor drives the vale to the open position untill the motor stalls and stays in that position. When the valve is required to close then power is removed and a spring return drives the mechanism ( and the motor) backwards to its original closed rest position.<br />
<br />
=== 3-port ===<br />
The valve has 3 pipe connections, in a '''T''' formation. The centre leg of the '''T''' is the inlet and the two short arms are the outlets, usually referred to as ports '''A''' and '''B'''. Actuation controls whether the flow from the inlet passes to the '''A''' or '''B''' port. In the resting state flow is to the '''B''' port (usually the hot water circuit). <br />
<br />
[[Image:CH_motorised_valve_Honeywell_mid-pos.jpg|frame|'''Honeywell 3-port mid-position spring-return valve''' Probably '''the''' most common type and make of valve found in domestic CH systems. Note the flushing lever shown just behind the black cable on the left]]<br />
There are two types of 3-port valve:<br />
; Diverter valve<br />
: This is a simple change-over version of a 3-port valve: when the valve is actuated all flow is diverted from one port to the other. When deactivated, a spring returns flow back to the original port - there is no mid position that can feed water to both ports at once.<br />
<br />
; Mid-position valve<br />
: In this type of valve there is a stable state in which flow from the inlet can pass to both ('''A''' and '''B''') outlet ports simultaneously. This type of valve is commonly found in domestic central heating systems where it controls flow of hot water from a boiler to hot water and radiator circuits in a [[Central_Heating_Controls_and_Zoning#CH_and_DHW_zones:_Y-plan|Y-plan]] system configuration.<br />
'''<br />
It should also be noted that these mid position valves usually contain a lever underneath the motor head. This can be used to move the valve physically to the mid position for flushing the system. This is used when refilling the system and bleeding all the air out of the system. After use it must be returned to the default rest position as driven by the spring (B HW demand) <br />
<br />
These 3 port valves were originally pioneered by Honeywell to support their Y Plan. A particularly annoying feature is that the valve had no physical valve position indicator (as per the Switchmaster below). This was a time waster for a technician faced with a faulty CH system and possible sticky valve. Even the modern Sunvic MoMO valve only has a rudimentary mid position indicator which can be difficult or impossible to observe. An experiment has shown that a coloured disc can be fitted around the valve shaft once the motor head has been removed - easy job not invalidating the guarantee. It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down.'''<br />
<br />
== Types of motorised valve ==<br />
<br />
=== Spring return valves ===<br />
In these types when power is applied the motor and gears act against the force of a spring to operate the valve. When power is removed the spring returns the valve to its resting position. In a 2-port valve this is the closed position. In a 3-port valve the resting position is where flow from the inlet passes to the '''B''' port (DHW).<br />
<br />
These types of valve consume power whenever they are open (and, in the case of 3-port valves, often even when they are not). In 2-port valves the motor runs until the valve is fully open and then stalls as the actuator mechanism cannot move any further. 3-port valves are more complicated: a description can be found in the [http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm uk.d-i-y FAQ]. An example of how a 3-port valve integrates into a system:<br />
<br />
[[Image:YplanSchematic.gif|512px|Click for larger image]]<br />
<br />
For detailed wiring diagrams of Y Plan and other zoning systems see the main <br />
<br />
[[Central_Heating_Controls_and_Zoning|CH Zoning article]].<br />
<br />
=== Motor On / Motor Off (MOMO) valves ===<br />
<br />
In these types of valve the motor is used to drive the motor from one position to the next. Switches in the mechanism stop the motor when it has reached its desired position.<br />
<br />
Since the motor only runs whilst the valve is changing from one state to another there is a saving in energy compared to valves where the motor runs continuously while the vale is open. Such valves may also be more reliable since the motor and surrounding components will run cooler.<br />
<br />
==== 2-port ====<br />
<br />
This type of valve changes from it closed (off) to its open (on) position when power is applied to one terminal, and from open to closed when power is applied to another terminal.<br />
<br />
[[Image:2PortMoMoValve.gif]]<br />
<br />
These types of valves are occasionally found in domestic central heating systems: usually as '''Satchwell''' or '''Sunvic''' valves with grey plastic heads. [[#External Links|Sunvic]] manufacture both MOMO and spring-return valves in similar casings.<br />
<br />
If a motor-open/motor-close valve is replaced by a spring-return valve, or vice-versa, the controls wiring must be modified to suit. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat (or progstat) and an extra wiring conductor between the 'stat and the valve.<br />
<br />
<!--- gaah! I've had to put the following text and the associated picture into an invisible table to prevent the text of the following section getting wrapped to the left of the picture, which looks wrong since the following section is nothing to do with the picture. --><br />
<br />
{| style="width:100%" border="0"<br />
|-<br />
|valign="top"|This type of valve is also found in non-domestic installations. <br />
|[[Image:CH motorised valve 2-port industrial.jpg|frame|'''Industrial 2-port motorised valve'''<br />
<br>The large orange box on the right houses the motor and gears.<br />
<br>The smaller orange box on the left contains the switches.]]<br />
|}<br />
<br />
==== 3-port ====<br />
<br />
[[#External Links|Sunvic's]] SDMV series 3-port valves are motor-open/motor-close types but are wired identically to spring-return valves. Since they only consume power when moving from one position to another (A to mid-position, mid-position to B, B to mid-position and mid-position to A) they save electrical power compared to spring-return 3-port valves. Compared to the Honeywell-type 3-port valve's 2 microswitches, one diode and 2 resistors the Sunvic valves contain more electronics: two relays and 3 micro-switches. Additionally they use two circuits each comprising a mains-voltage capacitor, bridge rectifier, electrolytic capacitor and diode to drive the relays which are 24V DC coil types, rather than using relays with mains-voltage coils: presumably the latter would be larger and/or more expensive than components of these circuits. However despite the (still relatively modest) amount of electronics in the Sunvic valves they may be expected to be more reliable than the spring return valves since:<br />
* the motor does not have to overcome the pull of the spring when moving towards the B position, and uses the motor rather than a spring to return all the way back to the A position, so a motor of given power can deal with greater friction in the mechanical components of the valve before failing to operate it properly<br />
* the valve head runs cooler as it is not dissipating heat from the electrical current passing for hours on end, which should reduce heat-related failure of components<br />
<br />
===== Switchmaster =====<br />
<br />
'''Switchmaster''' valves with bright blue plastic heads are found in some older domestic installations. <br><br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(end).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(top).jpg]]<br />
[[Image:CH_motorised_valve_Switchmaster_3-port_mid-pos_(inside).jpg]]<br />
<br />
* A [http://groups.google.co.uk/group/uk.d-i-y/tree/browse_frm/thread/e0dbe785f96b1fd5/5e1d68bc6f5b6b77?hl=en&rnum=1&q=switchmaster+va1&_done=%2Fgroup%2Fuk.d-i-y%2Fbrowse_frm%2Fthread%2Fe0dbe785f96b1fd5%2F7a62c7dcf1d4a074%3Fhl%3Den%26lnk%3Dgst%26q%3Dswitchmaster%2Bva1%26#doc_592aeebb15be127a thread on uk.d-i-y] suggests that these are '''NOT''' wired as for spring-return - cf Y Plan schematic diagram above).<br />
<br />
{| border=1; cellpadding=6 <!-- border: 1 is on, 0 is off; cellpadding is space (pixels) between text and border --><br />
| red<br />
| sw live to boiler & pump<br />
|-<br />
| orange<br />
| HW on (from cylinder 'stat)<br />
|-<br />
| white<br />
| HW off (from cylinder stat)<br />
|-<br />
| yellow<br />
| CH on (from room 'stat)<br />
|-<br />
| blue<br />
| neutral<br />
|-<br />
| green/yellow<br />
| earth<br />
|}<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/68c6cd970a83291e Another thread] discusses wiring and plumbing changes required to replace this type of valve.<br />
<br />
===== Drayton Flow-share (3-port MOMO) - discontinued =====<br />
<br />
This MOMO valve from the 1970/80s has largely disappeared. The actuator used just 4 wires: a neutral and 3 others (only one of which was live) which drove the valve to each of the 3 positions. <br />
The design is far better than most modern designs with the following features:<br />
* There are no electronics in the actuator (the Sunvic MOMO valve has electronics which are prone to failure). Valve positioning is done via a single relay in the wiring box and 4 microswitches in the actuator.<br />
* The low gearing means that the motor can still move the valve as it stiffens up with age (although it takes 2 and half minutes to move from end to end).<br />
* The motor gearing is all metal (the Sunvic MOMO valve has plastic gearing).<br />
* There is a valve position indicator which is also a manual override (allowing the valve to be put at any position quickly by hand). The valve re-engages with the actuator when they next align.<br />
* The weak spot was the large single piece plastic cam used between the motor and the valve. Eventually the metal parts started to grind away the plastic at one end or the other and spares were no longer available (although [[User:A_tranter|this author]] has rebuilt both ends of his cam with metal parts and it has been running now since 1978).<br />
* The usual MOMO advantages of only drawing power when changing position and being positively driven in both directions.<br />
* The wiring was quite complicated when it first appeared (1970s?) so whilst installation was straight-forward, maintenance was difficult for plumbers with no knowledge of the system. The wiring is not compatible with modern spring return 3-port valves.<br />
<br />
Unfortunately the excellent design was discontinued, possibly because they didn't fail for 15-20 years by which time 'better' valves with shorter lifespans had been invented by the plumbing industry.<br />
<br />
[[Image:Drayton-valves.gif]]<br />
<br />
== See Also ==<br />
<br />
* [[Central Heating Controls and Zoning]]<br />
<br />
== External Links ==<br />
[http://www.sunvic.co.uk/motorised_valves.htm Sunvic motorised valves]<br />
<br />
[[Category: Plumbing]]<br />
[[Category: Heating]]</div>John Stumbleshttps://wiki.diyfaq.org.uk/index.php?title=Underfloor_Heating&diff=13231Underfloor Heating2010-05-21T10:52:35Z<p>John Stumbles: /* Rehau */ update link</p>
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<div>''See the [[Central_Heating_Design#Underfloor|Central Heating Design article]] for pros and cons of underfloor heating compared to radiators etc.''<br />
<br />
The use of warmed floors to heat spaces goes back at least to the Romans who used [http://en.wikipedia.org/wiki/Hypocaust hypocausts] to heat buildings using wood as fuel. Modern Underfloor Heating systems ("'''UFH'''") can be [[Central Heating Design|designed]] and installed as part of a wet hydronic [[Central Heating]] system or can be separate Electrically heated areas.<br />
<br />
The following regards wet CH-based systems:<br />
<br />
== Suppliers ==<br />
<br />
=== Uponor ===<br />
<br />
[http://www.uponorhousingsolutions.co.uk/ Uponor] (formerly '''Wirsbo''') are long-established suppliers of UFH. <br />
<br />
{| style="width:85%" border="1" cellpadding="2"<br />
|-<br />
| Their web site's pages carry the now-common indication of the path through the document tree to the current page e.g. <br />
: Products > Underfloor Heating > PEX 15 Pipe<br />
but you can't always get further along the path from a given page! Instead you have to use the pop-up menus from the navigation bar on the left of the page.<br />
|}<br />
<br />
Requires (free) registration for <br />
[http://www.uponorhousingsolutions.co.uk/RegUsers/downloads.aspx PDF datasheet downloads] including:<br />
* [http://www.uponorhousingsolutions.co.uk/Downloads/Installation%20Guide%20for%20Domstic%20UFH%202006.pdf illustrated design & installation guide]<br />
* [http://www.uponorhousingsolutions.co.uk/Downloads/wirsbo%2020%20design%20guide%20may%202004.pdf Design guide]<br />
* [http://www.uponorhousingsolutions.co.uk/Downloads/Kanmor%20360e%20Weather%20Compensator.pdf weather compensator]<br />
<br />
Uponor supports installation in screeded solid floors, suspended floors with spreader plates or with their proprietary system using metallised bubble-wrap backing, and floating floors with 50mm panels.<br />
<br />
=== Continental===<br />
[http://www.continental-ufh.com Continental] are a significant established supplier of UFH in the UK.<br />
<br />
Their wesbite details the range of products which includes multi-layer AluPEX pipes and 5-layer PEX pipes. Their founder (Chris Ingram) is Chairman of the Technical Committee of the UK trade associaition, [http://www.uhma.info UHMA].<br />
<br />
Downloads available include:<br />
* [http://www.continental-ufh.com/download/CUFH_quote_form_web_r311007.pdf Free quote form]<br />
* [http://www.continental-ufh.com/download/CUFH_bro07_web_download_r311007.pdf Brochure]<br />
<br />
Latest industry [http://www.continental-ufh.com/news.asp news] and advice on [http://www.continental-ufh.com/floorcovering.asp floor coverings] is available<br />
<br />
Continental systems support installation in screeded floors, fit from above or below systems for timber joists, suspended floors and floating floors.<br />
<br />
<br />
=== Hepworth ===<br />
[http://www.hep2o.co.uk/quotes.htm Hepworth] (formerly '''Bartol''') are another long-established supplier of UFH in the UK. <br />
<br />
UFH Guides avalable as PDFs including:<br />
* [http://www.hep2o.co.uk/ufh/UFHFloorConstruction.pdf floor construction]<br />
* [http://www.hep2o.co.uk/ufh/UFHFloorLayouts.pdf floor layouts]<br />
* [http://www.hep2o.co.uk/ufh/TrainingGuide.pdf training guide] 'benefits' and installation practise<br />
* [http://www.hep2o.co.uk/ufh/UFHConservatoryPack.pdf conservatory pack] simple packaged kit for single solid-floored rooms using flow-limiting temperature valve in return circuit<br />
Supports solid, suspended and floating floors.<br />
<br />
=== Polypipe ===<br />
<br />
[http://www.polypipe.com/polypipe/products/building-products/ufch Polypipe UFH systems] (widely available in DIY outlets e.g. B&Q)<br />
* [http://www.ufch.com/ Trade site]<br />
** [http://www.ufch.com/Downloads/02-dandi-guide.pdf Design and Installation Guide] [PDF]<br />
* [http://www.freeyourwalls.com/ Consumer site]<br />
<br />
Floor types supported include [http://www.polypipe.com/polypipe/controller?action=BP-Products&categoryID=283 overlay] 18mm thick using 12mm pipe.<br />
<br />
<br />
=== John Guest ===<br />
<br />
(Makers of '''Speedfit'''). <br />
<br />
Their [http://www.johnguest.com/linkpages/UFHinstADV.htm UFH web page] gives a comprehensive guide to:<br />
* basics of UFH<br />
* solid floor construction<br />
* design principles<br />
* controls<br />
* heatloss (with R values for different surface finishes)<br />
* pipe layout<br />
* output tables<br />
* installation practise<br />
<br />
=== Nu-Heat ===<br />
<br />
http://www.nu-heat.co.uk/<br />
<br />
=== Osma ===<br />
<br />
http://www.osmaufh.co.uk/<br />
<br />
=== Rehau ===<br />
<br />
http://www.rehau.co.uk/building.solutions/underfloor.heating/floor.systems/floor.systems.shtml<br />
<br />
=== Royalle ===<br />
<br />
Supply a range of typical UFH systems but also make a thin (15mm or 25mm finished) screeded system based on zinc-plated steel honeycomb which, it is claimed, can be laid over existing wooden floors, even those in poor condition. The system is also claimed to have relatively short warm-up and cool-down times.<br />
<br />
* [http://www.royalle.co.uk Royalle web site]<br />
* [http://www.royalle.co.uk/max4therm_underfloor.html Max4therm thin system]<br />
<br />
=== Floorheater ===<br />
<br />
System comprising thin "poly" panels grooved for PEX pipe with bonded foil heat diffuser. Panels can be cut with a craft-knife, and glued, screwed or nailed onto surface.<br />
<br />
Also available in thicker "Easy Panel" incorporating insulation.<br />
<br />
* [http://www.floorheater.co.uk/ Floorheater web site]<br />
<br />
[[Category:Plumbing]]<br />
[[Category:Heating]]<br />
[[Category:Floors]]</div>John Stumbles