Heating wont turn off

[PeteK]

I've got a fully-pumped gas CH & HW system. My problem is that the boiler fires even when the control unit (timer) says that both the CH and Hot water are off. I don't have a separate frost thermostat (unless its built-in to the boiler - a British Gas "F2"). A British Gas engineer did call, and replaced a motorised valve motor, but that made no difference at all.

I was under the impression that the valve could not operate the boiler unless the timer was in the "on" position. The BGas engineer said that I was wrong (and he's the expect, not me) but if he's right, what is the point of the timer anyway ?

Any suggestions that don't include calling in British Gas would be greatly appreciated.

TIA,

Pete K

[ARWadsworth]

Look at

check what sort of system you have. If it is an S plan then I would suggest a faulty valve not just a valve motor. Adam

[PeteK]

Adam,

Thanks for the tip, I'll have to study the diagrams and try to determine which one I have, but at first glance it is eother an "S" or a "Y".

Cheers,

Pete K