supporto auto per palmari qtek s100 jeep wrangler roma hard cam piedi italiani www immobiliare il ponte it giradischi aiwa slaipotesi alternative celebrita sxy aggressor storia calcio agriturismo lerici cd giorgia everybody gotta learn sometimes pioneer televisione plasma fabio lety sumer jam 2003 atlantic schilly 3 testo quando volveras centro sportivo strani giorni una donna per amico marea 16 super mop malerba video clips usher lavoro cesenatico lusitano polacco italiano bromes www pantene c l surgun altec lansing 4 1 epiphone les paul hub usb frontale hp compaq ipaq puzzle hentai belle infermiere tutto bungaro hpcompaq ipaq rz1710 pocket pc vendita vettura batman 10 las cartas sobre la mesa raul ornelas olympus xd 512mb shape works citta di bayonne marta wisniewska here i go again dirty dancing 2 havana nights kazaa 243 stilo 19 jtd masterizzatore dvd rw elif ece barebone vendita affitto venezia epson t028 super trombate povera sora manga porno terni bmw 328ci infanzia vocazione e prime esperienze di giacomo casanova veneziano f1 manager i truffatori la noche cubana cd www studioaperto san bernardo piccolo paparizou prezzi della fiat 1500 nuova audi sportback dsg diesel auto calcio classifica serie b l ispettore gadget lultimo caso cattivi cu cross racing championship 2005 pornostar italiane free mx 1000 logitech boogeman ricetrasmittenti intek danimarca vasco un senso casio ex s500 nikon 80 200 d dscp100 p120 flash card canon integratore proteine formula one 04 the reasor paranoid android istituti commerciali di stato gioie testo inno champions league tempesta a liverpool delgadillo monitor lcd 17 silver reggae free his eye aureal sq2500 recorder dvd dvix age of myth titans nba courtside 2002 ibm hard disk e floppy cavi component lexmark cartucce inkjet la playstation 3 in un thriller californiano marino alessandro gazzetta martesana citroen 2 volkswagen polo 1400 diesel free movies informatica point sas ortodossia voisine roch goma anna e il re del siam honda varadero moto router adsl 8 porte gigaset a 100 siemens cordless bouquet di fiori juegos juegos com pregnant petrus de dacia empire heart angel mugler nero recode 2 suonere parlate musica populara dfi lanparty ut nf4 ultra lucariello mc s starlight lyrics seat milano sky italia softcam risultati esame avvocato 2003 mitsubishi eclipse lettore divx portatile tv volo messico programma audio per cd eskimo sport telefono con lettore mp3 e memoria ballerini amici manuela folliero mio mitac 168 oil spills video emozione per sempre sms sensuali freek a leek punto star 1999 supporto a ventosa palmare nbr case vacanza palermo no frost whirlpool un uomo facile san salvador radio edit cage bird alicia keys the space rebel mappi srl www analaura resistire masterizzatore usb masterizzatori cd sunn agriturismo vieste case prefabbricate auto asus 15 sxga dawn of the zombie stelle della moda w google it javanoid ii chere mark adventures goodnight moon shivaree painting cavalieri di colombo songs mp3 offerta playstation batteria motorola per v3688 colchicina hotelsex com ritter georg august dietrich windows media center computer parah www guadalupe com ar enzo maiorca renato magari video telefono cane king ciak la tana della volpe rossa piratas del caribe manuale winmx radebeul calendario aida yespica palmariva eretria www sborrami gay km0 alfa romeo diesel auto km 0 jeans diesel pantaloni uomo nwes 2004 noi non siamo angeli turtule vudeo porno senior buyer (italia nord ovest) le 4 stagioni apple ilife reggia caserta natale de gregori 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).
Motorised valves generally comprise:
- a synchronous electric motor
- gears to reduce the speed and increase the torque output of the motor
The motor and gears are often combined in a package known as a Synchron motor.
- a linkage from the output gear to the hydronic part of the valve
- one or more switches (usually microswitches) actuated by, for example, a cam attached to the output linkage
- a spring: see below
- the above components usually comprise one module, often known as the 'head', which may be detatched from the parts below for repair or replacement.
- a valve controlling flow of water in the hydronic system, actuated by the head: this part is often known as the 'body'.
Configurations of motorised valve
Valves are commonly found in the following configurations:
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.
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 A port.
There are two types of 3-port valve:
- Diverter valve
- This is a simple change-over version of a 2-port valve: when the valve is actuated all flow is diverted to the B outlet.
- Mid-position valve
- 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 Y-plan system configuration.
Types of motorised valve
Spring return valves
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 A port.
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 uk.d-i-y FAQ and here is a diagram showing a 3-port valve in a Y-plan CH system
Motor On / Motor Off (MOMO) valves
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.
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.
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.
ENERGISE ENERGISE TO CLOSE TO OPEN | | white yellow | | o o / / o/ o o/ o------- orange ----> TO BOILER | | | | ----------- ----------- | ------- | | | MOTOR | | | ------- | blue | NEUTRAL Switches are shown in their non-actuated states which occur when the valve is neither fully open nor fully closed. The switch on the left operates when the valve reaches its closed position. The switch on the right operates when the valve reaches its open position.
These types of valves are occasionally found in domestic central heating systems: usually as Satchwell or Sunvic valves with grey plastic heads. Sunvic manufacture both MOMO and spring-return valves in similar casings.
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.
|This type of valve is also found in non-domestic installations.|
Sunvic's SDMV series 3-port valves are motor-open/motor-close types but are wired identically to spring-return valves.
These Switchmaster valves with bright blue plastic heads are found in some older domestic installations. The author is unsure whether the wiring of these differs from that for spring-return valves.