Hot water ok ,but central heating won't work?

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