Baxi boiler trips without apparent cause

[Slaydeuk]

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.

 

[gas112]

Boiler gets it power through the clock then roomstat/cylinder stat then through motorised valve/s microswitch .
With programmer on and boiler not working check for power at and through room/cylinder sat . then make sure the actual motor on motorised valve/s have motored over to make the microswitch inside allowing live to go to boiler and pump.
Motors are known to break down under use and come back off of the microswitch thus cutting power to boiler

 

[Slaydeuk]

Thanks gas112. I suppose I'll have to wait until the problem occurs again to be able to track the power supply through the various components you list.

 

[petertheplumber12]

If you can't trace fault easily and need to go away, bypass the programmer for heating and go straight into room stat and set it on a low setting say 10degrees C and leave boiler stat on middle setting. If you have an immersion heater and you are likely to use it, make sure it is a modern one with overheat cutout the old type are dangerous.

 

[Slaydeuk]

Thanks for that. I'm about to start trying to trace the fault.