Baxi Combi 80e flame failure?

I had exactly this problem on my Baxi 105e. The fan would run and it would have a few abortive tries and then it would give up and start flashing the flame failure LED (sometimes with or without the fan failure LED). I changed the pressure switch (£24) and the fan (£102), to no avail. My third attempt was to change the PCB (£122), and it has fixed the problem.

Looking back, I wish I had trusted my instincts....... Originally I tested the pressure switch was actually switching the power using a 240v test screwdriver and it indicated that it was working OK. I needlessly changed the switch and fan because of the fan LED flashing. Then, when I removed the PCB, there was an obvious burn mark around one of the terminals on the back, indicating this was definately the problem - wish I had looked in the first place.

Other comments - replacing the fan is far more difficult than it first looks - Replacing the PCB is easy, but the actual replacement part is slightly different to the original, so refer to the wiring diagram on the back of the front cover.

All-in-all its fixed for £248, which is probably what it would have cost to get a boiler man in!!! (You win some, you lose some......)

Davy the hapless DIY'er
November 2009

I have taken off the cover to the heat exchanger and watched the two electrodes as the boiler tries to reset - only one of them seems to be sparking. Is that normal? On a couple of occasions the gas has ignited for a split second. Im not sure if this would help with the diagnosis?

Someone has suggested to me that it may be the fan not functioning properly. Maybe the air pressure switch failing? If this was the case, would this stop the boiler from lighting?

midvale99
November 2009

it sounds like to me there maybe no gas coming through,the gas valve needs checking,or it could be a fault on the flame rectfication side so the cable needs checking including electrode.or pcb

sw plumbing
November 2009