Boiler cutting out

Very unlikely to be the pump - if that fails, the overheat stat *will* trip and the boiler will then do nothing at all.

Does your boiler have a row of (maybe 3) LEDs which come on in sequence during the firing cycle? If so, how many of these are lit?

The boiler is clearly *trying* to fire - otherwise the fan wouldn't run. Depending on how far it's getting through the firing cycle you could have a problem with the pressure switch, pilot solenoid, ignition system or main gas valve. It's also possible - perhaps even likely in view of the fact that it seems to be temperature dependent - that you could have some iffy electronic components on the control board.

Agree with you here if the pump failed completely but the pump is at a guess 13 years old its pumping but I wonder if its not pumping as efficiently as it once was and the flow rate through the boiler has been dreuced therefore raising the temperatire within the boiler.

Only one light comes on when a demand for heat is required and this does light up.

Have put in a new pressure switch and I can hear that switching. The PCB is new as well so doubt that is at fault.

Still baffled.

Andrew

I had a similar problem and it was down to the fan ,it did this for a while then eventually failed completely,I sourced a second hand one from

Alex

In message , Set Square writes

No it's a stelrad 7b pcb

no disco lights

Although it looks like a pcb fault to me, I can't see what would be susceptible to such temperature problems

In message , a_mcbride writes

Has the pilot solenoid failed?

In message , Alex writes

I'm always here