intermittent flame failure main combi 24 he

[byronelvis]

hi guys.
my fault finding is pretty basic, so usually stick to installing but usually post on here before/if i attempt a repair to save myself losing a fortune ,haha.so any experience always welcome.
anyway... intermittent flame failure on DHW and heating as reported by my mate. when i went today reset would not get it to fire as it had been doing for mate but he has not tried it within the last month as he works away so it is no longer intermittent.
Pump runs,fan spins strongly, i removed the clear pressure switch tube from the fan venturi and gently sucked.the pressure switch clicked but sounded a tad 'spongey" rather than the usual crisp click that other makes usually sound.no attempt is made at ignition.there is gas at the inlet on the valve,no signs of resistor burn out on the board but i did notice the condense trap was completely dry.i thought this strange as it does not look to have leaked, rather dried up or evaporated.
anything obvious to you guys that ive overlooked or you need me check?
cheers
Brent

 

[Agile]

Sorry but this is a gas/combustion related problem.

You need to ask gas questions in the combustion chamber part of the forum where we can try to help you.

Tony