Ok where do i start, boiler intermitantly locks out, have take fan assembly out and cleaned all pipes, checked sparking electrodes, and seem to be ok, have swapped PCB but can not get boiler to fire. Pump runs, fan cuts in, igniters fire but no flame is it air pressure switch or gas valve etc. Has anyone got any clues

Darren, February 2009

if ignition takes place at electrodes, but no flame then you need to see if they is voltage at gas valve? if their is voltage then gas valve is at fault because it is not lifting the solinoid. however if flames ignite then goes out you need to be checking flame sensor eighter at electrode or at pcb thanks. remember you need to be corgi registered to do this work. john

john, February 2009