Baxi 105 HE APS or PCB failure?

8 Mar 2007
Reaction score
United Kingdom
My boiler pilot light goes off and on intermittently. The fan seems to stay on but the pilot light doesn't. You can sometimes hear the boiler re-igniting several times before it either stays off or stays on and then you can sometimes hear it re-igniting over the operation period. It is intermittent and can fire up with no problems on occasions. Twiddling with the tap or switching it off and on can trigger the pilot back into action. My problem is everyone is off a different opinion what it is, APS, PCB and Divertor Valve. I don't mind getting it repaired but I don't want endless costs till someone gets it correct.

Any ideas would be appreciated.
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If the APS was faulty would the boiler not fire/ignite at all or could it still fire up intermittently?

Thanks in advance
Yopur boiler does not have a pilot it just lights the gas when it needs to.

You need a competent CORGI to diagnose the fault and correct it.

You should not pay for any parts fitted which do not correct the fault. Its not your fault if he makes an incorrect diagnosis.

We always charge to diagnose a boiler fault and it seems as if you are getting people to come round without paying them! If you dont pay them then you can hardly expect them to give you free diagnostic work.


Thanks for the reply.

I havent had anyone round at the moment becuase I wanted to get an idea of where the problem may lie hence put the question on the forum.
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My car doesn't always start. Can anyone advise what the problem is, over the net? Unlikely.
Someone who knows how it works, has to be there.
Yes appreciate where you are coming from but from the symptons mentioned someone might be able to indicate where the problem may lie.
Yes appreciate where you are coming from but from the symptons mentioned someone might be able to indicate where the problem may lie.

The problem lies within the boiler. Its a gas train problem which means that we cannot give detailed advice to anyone who is not CORGI registered.

In any case its impossible to diagnose exactly whats wrong without being there and inspecting and testing the operation.

There are lots of posts on here which have been submitted by no CORGI registered people but have been answered....All im after is in indication as to whether the problem may be with the APS or PCB. If the APS was faulty would the bioler not light the gas at all
APS, PCB and Divertor Valve.
Ive seen dodgy flow switches and thermistors cause similar problems but seeing as you don't know a pilot from a burner flame I too am not prepared to take you in any further. I just want you to know that there are cheaper things that could be the cause of your problem but if you want to see my asre in Binn's window then tell me it was the diverter valve that was causing it.
It's hard to say precisely what's wrong from here as already stated, but it shouldn't be hard for a competent corgi repair engineer to get to the bottom of it with the boiler in front of him.
The divertor valve was changed approximately 1 month ago. #

The same problem is also seen when CH is turned on

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