potterton performa 24 no heating or hot water

Hi guys im a registered gas engineer and i have a problem which iv not come across before,wondering if anyone can help?
I was called out to a breakdown on a potterton performa 24 which is also a baxi 105 (same boiler just rebadged)
this boiler broke down and another engineer came out to it replaced the pcb and left it not working with the spark generator missing and the wiring to it in dissaray. the engineer didnt go back to it for 2 weeks hence i was asked to fix the boiler, so no problem jumping onto someoene elses work it was okd by the other guy!
Now i checked the usual, divertor valve,240v to fan,correct feed to air pressure switch,replaced spark generator and lead,replaced safety thermostat cut out but still not working.
the boiler goes to flame failure (turn reset button anti clockwise to reset fan runs air pressure switch proves divertor valve operates but then goes to flame failure as no spark is generated)
after being on to baxi technical i have also replaced selector switch& wiring loom from m1 on pcb to pump and divertor.I found out that the pcb was not brand new but had been in storage on the other engineers van for a while.before iorder a brand new pcb is there anything else that could cause the problem?

Reverse polarity ...does it run on a "fly lead " ? is the house earthing good ?
Could be many things...but if the p.c.b was not fresh/new.............

I always power the PCBs for 2-3 minutes and then reset in one go for at least 10-20 seconds!

Dont know who you are working for or with but leaving a boiler not warking for two weeks seems pretty criminal to me.

In any case we have a special part of this forum where trade questions are best asked.

Tony

These boilers are not rocket science , you say you have checked for 240 volt on various parts but have failed to mention voltage checks on the obvious parts in question.

With a replacement board power up and immediately reset for 5 seconds.

eeyore9 said:

before iorder a brand new pcb is there anything else that could cause the problem?

Click to expand...

Join the Combustion chamber and I'll tell you.