Sime C/H boiler not firing.

[warpaint]

Sime Friendly Format 100e c/h boiler has stopped working. Following sequence of events... Pump runs, fan runs, air pressure switch clicks, then fan stops after a couple of seconds. Fans starts and so on. It never tries to ignite. Gas present, elecs obviously, water pressure OK. Same on DHW and c/h mode. Suggestions??

 

[Agile]

It sounds as if the ignition circuit is failed although the problem could be caused by a faulty air pressure switch.

APS is a CORGI job to test or replace.

PCB is expensive if its only the APS at fault.

Tony

 

[warpaint]

The diaphram is fine, suck and blow on the tubes and there seem to be no leaks. The fan stays running if you squeeze either of the tubes and hold the pressure, but there is still no attempt to ignite.