BAXI 105e - Intermitent ignition & removing connectors

[JoeNW]

I have a BAXI 105e. The boiler has started to fail intermittently (daily) with the flame LED flashing red, indicating an ignition fault. If I follow trouble shooting section H of the installation guide and do a reset it doesn't always clear the fault, sometimes takes quite a few attempts before the flame will come. I've had the combustion chamber open, everything is clean (and now cleaner) and the spark gap looks fine. As it will reset after a few attempts I'd assume the spark generator and PCB are OK. The PCB was replaced two months ago. The boiler is just out of warranty, having run for two years without this problem. Before I call out a professional I wondered if anyone could possibly give a clue to the cause?

When I went through the guide for checking the electrodes it required the power wires to the fan to be disconnected, I didn't actually do this, the power and gas were isolated and it didn't seem to interfere with removing the cover. The reason I didn't remove them though was because I applied considerable brute force but they didn't seem to be budging and I didn't want to end up with broken connectors. Is there a knack to removing these type of connectors? It looks like the wires are fitted into a plastic sleeve that fits over a bayonet connector. Do you have to squeeze the sleeve somehow or was I just a coward and I should have pulled harder?

Any advice much appreciated.

 

[Gas2Air]

Use a pair of snipenose pliers and gently weave the connectiions off. It sounds as though it's the electrodes and/or gas valve.

Either way get a pro in.

 

[JoeNW]

Thanks for the advice.

Suspect the gas valve may well be the cause. Noticed this morning that when the ignition is succesful I can hear a valve operate and a flow of gas shortly before the spark generator operates. When it fails to ignite there is no sound of gas flowing. So either the conditions for the valve to open are not being met all the time or the valve is simply failing.

I'll get someone to come in and fix it before it fails completely.