My boiler fires up every couple of minutes for about 10 seconds then shuts down again,there is nothing in the house calling for heat and i have turned the central heating switch off on the boiler leaving it running for hot water only.
this has not cured the problem.

nigel beviss, May 2007

Does the central heating come on properly if you switch the heating switch on? Is the first bit of hot water unusually hot?
The boiler has hot water priority and if the water valve is sticking on it won't allow the heating to respond and will keep trying to bring the boiler on for hot water. You may also find that the pump never shuts down. Need to know more..

T.H.S, May 2007