My biasi boiler works ok for hot water, but as soon as the central heating is put on, the boiler will not fire up. Has anybody any ideas why this would happen. I would be grateful for any suggestions

steve CG, October 2009

Agree with the above. The diverter valve can be very sensitive. Mine would not work because of a dripping hot tap. This slight demand for hot water caused the system to remain in the hot water position (i.e central heating off).

Changed washer and problem solved. Worth a check.

Kev, October 2009

im guessing you have a combi boiler... if so i should imagine that you have a faulty diverter valve. (this i understand is an electronic valve which opens as you make a demand for the heating) if the valve is failing then the boiler in return will have nothing to fire up for. I am not however, technical in the world of the lovely boiler.. but it does sound very similar to a problem i experienced a short while ago.
hope you get it sorted, and at worst you may be cold.... but at least you wont smell! good luck

danny, October 2009