Baxi 80Eco fault

[mikegas]

I went to look at this boiler on friday for my mates mum, she said it would fail to work intermittently either failing to fire up at all or working for an hour then cutting out, other times it would work fine but the hw had been luke warm for a while, another engineer has replaced the diverter valve about a month ago in an attempt to cure the hw fault.

so when I got there the boiler fired up fine for ch and hw but the hw was luke warm, I also noticed the outlet sealing collar which connects the elbow from the fan to the inner flue had split away so I thought that might be what was causing the intermittent fault as its just above the venturi, I replaced the collar and put the hw fault down to a blocked plate heat ex which is on order, she phones me today to say its failing to fire again so ive just been round and had another look and the pump runs, flow switch proved, fan runs at normal speed, i could hear the aps clicking over but it wouldn't go to ignition so I checked the pcb for any loose connections and as I pushed on the pcb it fired up but it then wouldn't go off even if I switched the selector to standby, so i'm thinking the pcb is goosed? could the pcb could also be responsible for the hw fault or am I looking at 2 faults? don't want to be stuck with a plate heat ex and out of pocket. Also does my diagnosis seem right or is there anything else I need to check before I order a pcb. Any advice appreciated as I don't do a lot of breakdowns. Thanks in advance

 

[diamondgas]

sounds like aps.... you can check the resistance though the aps when it switches.... expect 0 ohms or very low at least... comon intermittent fault is due to dirty conections on the microswitch The phex is a common one too. If the scale of lights on the front rise quickly then thats a good indicator to a restricted flow

 

[mikegas]

sounds like aps.... you can check the resistance though the aps when it switches.... expect 0 ohms or very low at least... comon intermittent fault is due to dirty conections on the microswitch The phex is a common one too. If the scale of lights on the front rise quickly then thats a good indicator to a restricted flow

There is no scale of lights on this boiler mate just flame indicator and flame failure lights

 

[arran197]

Check the NTC sensor on them too, they can give all sorts of issues if playing up. Might even be worth putting a new one on anyway if it's cheap enough. Causes intermittent firing cause it knows it should be on, but doesn't know how hot it's getting.

 

[mikegas]

The mi's do point to the pcb but i'll try a thermistor first as they are only a few quid, cheers