Motorised Valves

piedmont music gabry ponte geforce 6200 tc pcie toner samsung clp 510 bmw 316i kling gl disiz la peste clip art fantasmi manzanilla dragonsta din tei misa guardato a vista batteria ricaricabile 9v bouble booble nikon coolscan 50 www win magazine notthingam lollipop autoradio navigatore lake of tears sones jarochos ciao amico padre pio toni santagata video cartone porno fascia neoprene prepuzio video profilax player portatile casino on line valigia da viaggio zucchero dvd pupenude adsl magik giel sexy larticolo 2 xd 64 radiocomandi hitec gay passivi televisore lcd 32 pollici samsung fai che non hi fi a parete norton 2005 full dvd xp samsung syncmaster 913v cavity box per neonato femme a poil durna duran burrago cavo casio sami yusuf hinh khoa than ho ngoc ha bruno del turco cheba zina claudio baglioni amore bello capitan tsubasa itinerario vienna orologi fossil donna chiara conti acquedotto lucano in questo mondo di robots gigabyte k8n citroen c2 exclusive video registratore obiettivo canon 50 nuovi dettagli sul film di doom testo di buonasera dottore camera ferrara musica e totalitarismo batteria sony npfp 70 nas sata annuncio affitti ragusa manuela arcuri sexi mixer a 2 canali dwx unione democratici di centro nuova hyundai tucson il ballo del pio pio pamala hp pavilion amd athlon 64 rei e verde il compleanno europeo xbox canzoni russe ballo latino wondering radio majestic sp 10 il washington post punta su sony descargar revista d art 1 comma 336 kjs srl software ici 2004 dkvm 2k xantia 18 16v c2 nuova sistema 5 1 alfa gta dnc i cavalieri della regina sony vaio centrino dont tell my donne mature troie townsville tissue doppler riprese nascoste hp palmare h2210 gig nikko radiocomandati toquino testi montreal hotel www chirugia del pene com hanna manifestino www fuckit it foto di alessandra nuda batteria sony npfp 50 www quannhala com corsi di cucina in liguria scheda video fx eroticmanga amore trova anima gemella pavilion dv1250ea carioca village club pixma 4000 mezdeke un killer per lo sceriffo maras nicolas uribe vulcano figlio di giove immagini nokia 7610 rudy annuncio personali napoli dlink dwlg122 terme romagna ritratti i figli del nilo galeata comune di slot per pcmcia tom rider www campania e salutala per me apple 4gb plasma pioneer jacques levavasseur ragazzo frankfurt am main elezioni regione calabria 2000 ca orologio the prayer michael gray the weekend finanziamento fondo perduto hi fi dvd toner per canon ep 27 scuola romana rorschach annunci con viva street it allco spa peta www unina2 it jinxi sony vaio s4m s risparmio carburante vaccinazioni v ieni da me www caparezza it multifunzione hp stampanti elenco telefonico bielorussia siti di libri vajont marco paolini ragazzo di colore lettore mp3 portatile telecomando www lnd crl it rudy ectro azione avventura il tempo delle mele 1 sony cmt dv2d ben webster musica world basalto samsung yh 820 sdlt hp lladro com saldi estivi 2004 bachi da seta riassunto del libro di conan benq masterizzatore l angelo nero nokia hdr1 notebook 100 gb coppie over liviu guta si daniela gyorfi passeggino leggero lcd casio 2 5 infermiere puttane hdd 250gb frontalino lavastoviglie bmw alessandria caserma vigili del fuoco napoli op 102 no 4 beethoven altek srl www hitland com hacia la libertad 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