Baxi 80 he instant not firing up but no warning lights

[khlv374]

I have an intermittent problem where the boiler isn't firing on hot water and central heating demand but there are no warning lights and demand lights light up as normal. It's been reoccurring now for over 12 months. When I have investigated the wiring to the PCB everything looks fine. I've tried changing the PCB and this hasn't solved it. The boiler seems to go through cycle - pump runs, I can hear fan, but no clicks for ignition. Sometimes I open bottom, wiggle things around and then it comes back to life, but I can't pinpoint what I may have done to do this (all wiring looks fine!). It's really frustrating and if anyone can help me pinpoint where to look for this problem I would be very grateful.

Many Thanks, Paul

 

[adlplumbing]

couple possabilty but you would need an rgi to check it out

 

[45yearsagasman]

More than likely a fault inside the combustion chamber. For safety's sake get it repaired by a pro. Quite commonly not expensive to repair.

 

[khlv374]

I read some similar posts and there was one which said a gentle knock to the side of the boiler next to the APS got it working. I tried this when not firing up and all been ok since. Does this sound like a faulty APS? Wiring there looked fine and sensing tube was not blocked.

 

[Agile]

You should not have opened the combustion chamber as a DIYer.

Now to need to call an RGI to check/replace the APS and examinine the integrity of the case seal.

Tony

 

[Blooflame]

Mate, this is a dead easy one.
1/ Source a good and reputable Gas trainer
2/ Pay them several thousand pounds to gain the qualification
3/Pass your ACS (this actually allows you to work on the appliance).
4/ Locate the fault without exposing you or your family to premature demise or prosecution. Or..... hire a professional RGI. Can't apologise for my sarcasm but all the other lads have said it all.

 

[khlv374]

Well a recommended RGI came out while the boiler was in fault mode and ran some checks. Unlike what I thought previously the fan was not running. So to recap the pump is running, no fan, but no warning lights, only the usual demand lights on the panel where appropriate.

He rang BAXI and they took him through some diagnostic checks, which all pointed back to the PCB. However the PCB has been changed twice and the same fault persists. Therefore he believes some component of the boiler is intermittently throwing the PCB such that it does not send a signal to start the fan. Unfortunately that is all he could offer. If anyone has seen anything like this before or could suggest what component might cause such an effect I would be very grateful. I think the clue perhaps lies with whatever circuit wouldn't throw up a fault light.

Once he put everything back together it randomly started working again, but it will only be a matter of time before the next time. He recommended Baxi's boiler cover, but I'm worried of inconvenience during the winter and would much rather bottom this one out.

 

[picasso]

If the pump is running check the flow switch is making.