I have a 3 year old Baxi Solo HE boiler. Lately it has tripped twice. All three lights are off and, using the Baxi fault finder, I checked the electrical supply at the incoming terminals on the boiler - no power. At this time, the boiler controller in the kitchen is showing lights indicating that the HW and CH are both ''on''. Next to the controller is the main switch for the central heating and, for no particular reason, the first time this happened I switched the power off and on again. the boiler ''Mains On'' light came on and the boiler started. It has run OK for several weeks and today the same thing happened. I switched the power off and on again and the boiler started. Can anyone explain this and suggest how I can fix it. I don't want to go away on holiday in winter worrying whether the boiler is going to trip out again.