When i put my boiler on to central heating it fires up then runs for roughly 5-10 seconds then the flame goes out, then it re-ignites. It does this 3 or 4 times the goes into fault with a solid red light.I have checked the pump and it seems to be operating okay. Also when it is asked for hot water it acts similarly to when on central heating, it does however work on hot water, most times but not always, if the hot water tap is fully opened.

Scott Robertson, September 2008

What you said above, i assume it works however most times when hot tap open full, is that correct?

if so id be looking towards the low gas pressure setting.

ch fires on high then drops to low which is when it could be going out.
dhw open full would prob keep burner on high keeping burner fired.
dhw open partially, burner would have to modulate down to low and could be going out then.
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if it was faulting in the same way on both all the time id be thinking of a primary thermistor but seems more gas valve related to me.

maybe time for an engineer call as a quick 2 min check would confirm/rule out pressure problem

iain, September 2008