Sometimes my Myson Apollo 80Si boiler fails to ignite. the problem is that when this happens, the gas does not switch off and pours out through the flue.
I have had both the PCB and gas valve replaced but the fault still exists.
The modified lead was also fitted with the PCB
The boiler is currently condemned (obviously)with a sticker on it.
As the fault is intermittent, it can only be reliably generated by disconnecting the HT lead (I think that's what it's called !)
BAXI/Potterton still say it's PCB or Gas valve but I can't see it and they refuse to come out due to age of boiler(15yrs ish)
Can anyone help please.

Martin Smith, August 2007

Check that the pilot and main coils on the gas valve are wired correctly and not crossed over

Ian, August 2007

yes spark is fine now. original ingition problem ie not lighting was due to electrode being out of position. That was put right and it lights ok. The issue is that if you disconnect the ignition lead to stop it sparking, gas still pours out of the burner.

Martin, August 2007

If the main burner is coming on before the pilot lights then you are lucky it does not light, If you have had a gas valve and pcb fitted already then I would suspect that it is only the pilot gas that it is on. if you have already had a new ignition lead, then the only other 2 things left which are the cheapest and the ones i would have changed first are the spark electrode and pilot injector. does the spark look good when it is trying to light.

gary.wright53@googlemail.com, August 2007

The sticker says "Mains gas pouring through burner without a pilot being established".

I live in Somerset, near Cheddar.

Martin Smith, August 2007

If you have had someone condemn it what was the reason on the warning notice, what area do you live

gary.wright53@googlemail.com, August 2007