when heating is on the boiller keep comeing on then going off, so radiators are hot then cold hot then cold, its now started doing the same thing when the water is on, turn the tap on the water gets hot the boiler clicks off then on off then on, im lucky to get a hot bath, can any one help.

alison, September 2007

I had this problem on a Baxi Bahama 100 combi. Nearly drove me mad. After several days I changed the fan proving switch.
The rise in temperature in the fan compartment must have just pushed the switch into open circuit, shutting down the burner with no lock out. Boiler would then restart briefly. Naturally before cracking it I had bought an expensive PCB board to no avail.
Good luck.

Peter, September 2007