3 port valve

[AllyBongo]

Fitted a open vent boiler with a 3 port valve, spark wired it. I noticed when both demands are on and the HW is switched off the boiler cuts out, pump overun then relights. Should it cut out, I thought it would stay lit and the valve would just move

 

[Puddle]

No,it does go off then back on once heating mode achieved ,it is operating correctly

Which is why you often get the fault on older systems were the valve moves over but nothing happens as it does not move over enough to flick micro switch in valve due to ware and tear

 

[Roger Welton]

cuts out until limit micro switch makes and 240v is fed to orange wire. In h/w and mid position boiler and pump are fed 240v from cylinder stat.

 

[SafeGasInstall]

flame should not go out me think , however I have never actually checked on my boilers this tbh , it seems motorised valve cuts out and then makes the switch again , was it a honeywell valve ?

 

[AllyBongo]

Yeah honeywell with a Vaillant 428. Cuts out, temp goes down a bit then it fires back up

 

[Leo21]

Yeah honeywell with a Vaillant 428. Cuts out, temp goes down a bit then it fires back up

Yep they all do that.

 

[desrob]

Yep they all do that.

agree

 

[Hardy1]

aree^^

 

[jhon lennon]

i dont disagree