Motorised Valves

televisore 32 pollici puppet master il burattinaio hotel maria traveldock zen micro annuncio personali sardegna van halen right here right now ignis lavatrici foto annunci coppie esibizioniste free porn movies stati mascatilor windows 2003 small business geforce ultra una demo di tredici bionda in paradiso fingere monitor lcd 17 multimediale pivot tarocco zen osho praga rodolfo ii www sou par com eurosong 2003 processore intel pentium 4 3 2 ghz elisa bagordo amore com ef 500 dg st sigma flash pentax optio s 60 canti di kiko ballu i goblin libri noleggio auto avis vhs costa e ale tiziano ferro and jamelia universal play lo voglio grosso codreanu questione casetta prefabbricate paola sexy idata transcargo oh boys laverda spa dmr e75 box drive esterni lancia ypsilon multijet platino lancia delta integrale hf ferry boat www montecitorio philips 6010 elettrico valzer polka klezmer san martino in strada schede video ati radeon 9600 xt gesu e il signor berretti rossi vacanza 2004 birra scacchi animato assassinio per cause naturali lou x hokey air opus pistorum amore sublime pantaloni sport burger machine asrock 775s61 kipling margarita legge fallimentare matrix save screen pci x600xt hard disk portatile che cosa c e fuoco liquido usfamily net guia gai de mikonos city car oakley penny polished intelligienza www foto gratis it fray mocho jane slalom rebel supreme robbie williams casse golf 2003 kimberly nicole cameron divetente litle toni univision com musica aston martin db7 volante taroudannt severina vuckovic movie lamore senza limiti srednje skole titti e silvestro asciugamano elettrico via libera www dovecomequando it www dolcini com antonio tabucchi www insomnia it paris palace hotel abit as8 3rd eye etichette companie aeree fiori brindisi fiat marengo fiat grande punto diesel 5 porte amore maledetto traduttore simultaneo latino prezzo computer jeden osiem palm treo autorita di vigilanza cauzioni mia a he tastiera e mouse per playstation 2 milano malaga inviti alle feste parapendio palmare pocket pc hp fiat punto 1998 gpl dear anne il dono della speranza ricetta pasta mandorla peugeot 406 sw s5000 obiettivi pentium d 840 3 2ghz 800 2mb dualcore lettini fasciatoi buste salvaspazio bonbon kotto haute www gta san andreas com centro assistenza akai roma cordless aggiuntivi segreteria fax sodimm 512 mb ddr pc2100 gangsta band roxy t ferro con jamelia annuncio gratuiti personali foto el ultimo mohicano veglie di preghiera ufficio udine uomini superdotati la regione centrale sonsuz ol kloficker aeoliscus memory album joanne woodward televisore al plasma panasonic ati radeon x600 256mb auto da tuning key for art arabesque una questione damore nomi gnomi qormi vondrackova jovannotti ciao mamma base musicale trombate bollenti tara james calicino packard bell vt900 mala rodriguez roberto magi srl importo contributo integrativo cassa consulenti del lavoro epson aculaser cx11n video massacro ossezia hard c waffle gold nike speechfx ass munchers wake death shadow s m40x 128 www eurostar it toshiba 220 dvd raccolta log di attivazioni amd 64 3700 harrypotter com movilnet venezuela volkswagen polo aziendale formichi carlo ypsilon 1 3 multijet oro yamaha 1000 scandalo corfu il mio amino vende il mia ia hii affare cuore deurne (belgio) ragazze danesi www trucoteca warcraft com storia cinese lockheed martin ariston avtf 129 glasgow cose fare jeans diesel autunno inverno masterizzatore cd e lettore dvd video di eminem sborrata in bocca kawasaki er5 ferri stiro con caldaia polti hotel le grazie play station 2 gran turismo 4 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:

2-port

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.

3-port

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.

Honeywell 3-port mid-position spring-return valve Probably the most common type and make of valve found in domestic CH systems.

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.

2-port

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.

Industrial 2-port motorised valve The large orange box on the right houses the motor and gears. The smaller orange box on the left contains the switches.

3-port

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.

External Links

Sunvic motorised valves