My 70ff Boiler has had difficulty igniting. I would find that the fan was running but the boiler/rads were cold, after some coaxing with the rest knob it would eventually ignite. I think a faulty PCB and Thermistor may be the cause? I planned to tackle the job when the weather warmed up, however the problem seemed to have stopped now that the boiler is only heating the hot water (Y Plan system). But another problem has arisen, the pump over run seems to last far longer than it use to and hot water is being pushed up the vent pipe back into the feed and expansion tank. Has anyone else had this problem and does my initial view that the PCB /thermistor are faulty still hold?

Joe

Joe, June 2008

strange how your getting pump over from the vent with a bypass and two rads without trv's.
its not very often that you get pump over on a y plan as one route is always open.
its poss your cold feed from tank to system is blocked as that can cause pump over.

no heating most common a mid position valve fault.
poss the motor in the actuator first suspect

hi-spec plumbing & heating, June 2008

Hi
Bypass Valve fitted all but 2 rads (towel heaters) have TRVs

joe, June 2008

have you a bypass valve fitted to the system ?
have all your rads got trv's fitted ?

hi-spec plumbing & heating, June 2008