Hi my baxi 105e instant boiler is stuck in the hot water mode i.e light on constantly. The hot water works fine but it won't switch to heating also sounds like the fan or something is running all the time.

Gary Beresford, April 2010

fixing a boiler is generally nothing more difficult than replacing a defective part, but the following problem makes it difficult to identify the culprit.
- Central heating works ok.
- There is no hot water.
- Lights start with nothing, the upper red neon start to light up indicating temperature build up, then they all (just the upper red neons) start flashing insanely, and then cut off.

Robin Brown, April 2010

you need a new microswitch, and probably the diaphragm and seal replaced, they can leak causing the switch to short circuit causing a constant demand

Ian, April 2010