Another Potterton Housewarmer fault. Switches itself on and off when off at prog

[armyash]

Hi guys went to have a look at this tonight, customer switches boiler off at the programmer, it goes off. Then it comes back on again.

Any ideas?

Faulty programmer? Drayton LP5SS

 

[Chalked]

Sticking motorised valve end switch?

check orange wire for current.

 

[armyash]

So if i'm getting current at the orange wire with ch and hw off at programmer, that would be a stuck motorised valve, correct?

 

[Chalked]

So if i'm getting current at the orange wire with ch and hw off at programmer, that would be a stuck motorised valve, correct?

Probably.
But make sure that the brown is dead. If the brown is live could be prog or a back feed.

But yes, if the brown is dead and the Orange is live, it's a new motorised valve.