Potterton Suprima 50 not turning CH off via thermostat

[mcstarfish]

Hello, hope someone can help....I have a Potterton Suprima 50. When I turn the stat up to the click the CH comes on, no prob. However when i turn the stat down and it clicks again the CH still stays on!

If I turn the CH off at the programmer it STILL stays on! However if I turn the HW off at the programmer, then the CH turns off!!

Anyone got any ideas as to the cause of this fault? I read some other topics about this boiler & the pcb seems to be a common faulty component, could this apply in my case?

Any help would be greatly appreciated....thanks in advance...mcstarfish.

 

[ollski]

3 port valve passing?, does your heating come on whenever water is being called for?

 

[mcstarfish]

Thanks for the quick response Ollski, no the heating doesn't come on when water is being called for, it only comes on when the stat is clicked on......it's just getting the bl**dy thing off again that causes problems!...

 

[Garfeild]

Does the boiler keep going too?

 

[mcstarfish]

Not sure I understand your Q garfield - when I turn the stat down the boiler keeps going, when i turn the CH off at the programmer the boiler keeps going, when I turn the HW off at the programmer that is the only time that the boiler stops running, hence cooling the house down at last!

 

[Rob]

what motorised valve(s) do you have?

 

[mcstarfish]

Rob, Here's my system:

Potterton Suprima 50 boiler
Danfoss CP15 electronic programmer
Danfoss thermostat
Sunvic SD2701 3 port actuator valve
Potterton Celsia pump (code 8268E 0399)
Danfoss WB12 wiring box

Thanks again in advance....

 

[Rob]

some basic electrical checks would make it alot easier. fault with the electrics in the head of the 3 port is all i can think for the moment but as i said being there and carrying out some basic checks would probably make it fairly obvious.

 

[bster]

has the stat/programmer worked as normal befor this fault occured or have you just moved to this property?

 

[mcstarfish]

house is 10 years old, moved in two years ago, did have another problem when first moved in - the boiler kept shutting off - red led lit, reset didn't help - had to let it "timeout" & eventually would right itself & the green led would come back on. This fault seemed to fix itself after a couple of months although I did find by turning the temp on the stat on the water tank down slightly did seem to help?...

now this new problem has started....my gut feel is that the stat & programmer are working ok.....any other ideas?....i have seen other posts about the pcb & bad soldering joints...could this be possible for my prob? - I will check the pcb anyway and update tomorrow...

 

[Garfeild]

Sounds like the 3 way valve,if the boiler "ignores" what the room stat tells it to do.

 

[KNMSMOM]

ollski

does your heating come on whenever water is being called for?

Yes!!! Have tried everything from reseting boiler (Suprima 80) to turning timer off to turning thermostat off, but nothing will prompt it to go off.

If the heating has gone off on it's own and a hot water tap is turned on the heating comes on and nothing seems to make it want to go back off. I'm convinced that we have a monster boiler..Please help![/quote]