WE HAVE A SWIFTFLOW Glowworm 80 COMB-BOILER. It has not been used for over 6 months as house is being renovated. Now need to get things warmed up and get boiler working. The instant hot water from tap is working OK - the pilot lights up ok etc. But the Central Heating is not working at all and will not switch on. Also the fan is contiually going and will not slow or stop. Could it be that the pump has a problem - impellar not going round/stuck? or could it be electronic? Thanks for any ideas about this problem.