Check your gas valve - is the control knob still set in the 'Light Pilot' position? If so then the easy solution is to turn it into the 'Burner On' position!!
If this is not the case then check the gas valve is receiving a voltage - if it is and the burner wont light then the gas valve is faulty and will need replacing.
Gas58man, March 2012
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I can answer this question...
I have a Serwarm 50 Elite boiler which will not fire up although the pilot ?