my boiler lights the goes out every 5 or 6 seconds on heating and hot water flow and return clear pump running aps working fan working motorised head working have cleaned out plate to plate heat ex checked electrode connections at first i thought there was some dirt in heat ex or boiler parts causing it to overheat or stick somewhere but after 2 hours of investigation and checking micro switches and venturi it leaves me , with ignition box fault , pcb or something else .if any one can help it would be apprieciated thanx

browni, August 2008

does this happen when boiler has warmed up ? if so definately ignition box. (have you tried thirmister ) sounds like ignition box though.

gary, August 2008

cheers for that lads will check them out much apprieciated

browni, August 2008

possible earth fault like T says, also poss high limit stat, or sensor.

linea has sensor at h/ex and high limit on pipework to h/ex,

iain, August 2008

check your earthing, sounds like a flame recification issue

T, August 2008