Vailant Boiler problem

[alextg]

I have a Vailant boiler VCWGB 282EH that does not always light correctly. When the hot water is turned on the gas turns on, the igniter sparks, the gas lights but then immediately goes out, the boiler continues through this cycle until it either lights or locks out and has to be reset.

[jomifl]

Is the circulating pump working properly?

[terence7556]

does your central heating side work ok? if not what happens?

[alextg]

The circulating pump works fine, and both the hot water and central heating work fine if/when the gas fires up and stays lit, the problem is that it does not always light properly. The boiler goes through a rapid cycle, it sparking, the gas lights, then goes out immediately, then it sparks again, the gas lights and then goes out etc etc. It does this repeatedly until it either stays lit or the cut out button pops out. I thought it might be the flame sensor but I have changed that and there is no change.

[gucciman]

I would have been looking at the flame sensor too, could be a pcb problem.

[tamborine]

it may need a new thermacouple - they do burn out

[tamborine]

this is the thingy - dead easy to DIY, very cheap @ B&Q

http://homerepair.abo...ouple_replacement.htm