It was the microswitch that detects the water flow. It was sticking in the closed position.
A new microswitch from Maplin cost me £1.99
Saved me a fortune. Thanks for your advice. :D
Hi
When I turn on a hot tap the hot water light on my baxi combi boiler 80e comes on as you'd expect.
When I turn the tap off again the light stays on. This then prevents the central heating from comming on.
If I switch the boiler off and on again, the hot water light is reset and the...