how can i fix my baxi combie 105he?

its a fault on the diverter valve or the ch flow switch if you have the service manual look for the ch micro switch keep an eye on it turn of water and central heating. now turn on central heating and u should see a pin come forward and turn on the heating if the pin is already forward and does not retract when u turn of the heating its a faulty washer in the valve if it does retract and heating remains on then most likely faulty micro switch if all else fails new pcb gl

kash
September 2010