pilot lights fine. when calling for both heating and hot water pump runs but burner will not ignite or should i say very rare as sometimes it will, you here gas valve click and it fires but only on the odd occasion. this is a balanced flue not fanned with an old multifunctional valve with a nob to change to pilot on or off, electric supply seems fine to the boiler i can only think of gas valve, With the boiler being resonably simple but i cant be certain any advice would be a apreciated.

Tony, June 2008

The problem appears to be a malfunctioning solenoid which operates the main burner valve. Check that the two single cables that go into the gas valve are undamaged and are connected properly at the control panel end.
DO NOT undo or start exploring the gas valve itself.

cledlyn, June 2008