Potterton Suprima 40

[trooperman]

Winter is coming so turned heating back on and have got the same problem as last year. Hot water system works fine but heating only comes on when it feels like it. I've had Homeserve out but they didn't seem to know how to find the fault. They changed the PCB then room stat. Now seem to think it might be the Boilermate electrics, which they know nothing about. If I move the lever on the motorised valve that sometimes makes the heating come on. Any ideas??

 

[kevplumb]

have the valve checked

 

[SullyTheGoldfish]

trooperman,

did you get this sorted? if it's a boilermate II i can tell you what the different PCBs do.

Andy

 

[MANDATE]

sounds like the 3 port valve to me!
All depends if motor drives quadrant/valve beyond mid point. Suggest you remove the actuator head from valve and watch the D shaped hole as you try the various positions ie HW...........HW/CH..........CH.
I bet it never gets to the CH position because the valve is too stiff or the motor is knackered.
suggest you do search on 3 port valves