Air Pressure Switch
If it's lighting it's unlikely to be the APS, has to be something to do with flame detection. If the APS didn't make, the boiler would never light.
I have seen a problem where the HT lead to the ignition electrode was broken. The spark could still jump the break in the conductor within the insulation and light the flame, but the current for flame detection couldn't, so the gas would shut off. BUT, it wasn't on this boiler, which has a separate flame detection electrode (in the case I describe, the ignition electrode was also used for flame detection) so may not be applicable here.
I would test the cable to the flame detection electrode for continuity and replace if necessary.
i always replace both
as baxmax said check the aps and polarity
aps Air Pressure Switch
Maybe i am stating the obvious here but do you have your own registration? Competant?
If not you have already broken the law........this site doesn't facilitate diy gas.......other posters note this too
Quite apart from that, early on he said that the wire had been disconnected and it still faulted.
The problem is that he had employed a "plumber" who had no idea about boiler fault diagnosis!
Tony
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