when the hot water is heating up some of the radiators also get hot even though the radiator heat is not switched on. now i have wanted the radiators on they dont seem to get hot and the boiler doesnt seems to stay on unless the water is heating at the same time. i have tried bleeding the radiators but doesnt seem to of made much difference.

Debbie, October 2009

In the inside of your boiler there is a device called a diverter valve - which, as the name suggests, diverts heated water to either your radiators or hot taps...you don't get both. If this valve has stuck, you can get the symptom you describe.

John, October 2009