Sometimes the electrode fails and causes it to spark in the wrong place (called arking). Always start with the cheapest solutions. If you can see a spark and it fails to ignite this may be the problem. Do not attempt to adjust the gas flow pressures or anything like that. Call the experts.
Liam
July 2011
need further squence of start of boiler any noise, fan cycle etc
k
February 2011
I can answer this question...
Potterton Profile 80E, no pilot light on the boiler. ?
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