have u checked the minimum water level. Some systems shut down below 1.5 bar pressure and you have to top them up from the cold supply tap. This might be located at the cold water inlet of the boiler. This sometimes happens if you have a leak in the CH radiators. Bleed the air out of any radiators and then refill the boiler to at least 1.5 bar and see if it kicks in.
Richard
August 2006
I can answer this question...
my hot water and heating is not coming on, on my worcester combi boiler?