my baxi 105e when you call for hot water it fires no problem and delivers ok. But when you switch the tap off the green led stays illuminated and wont switch back to central heating. If i switch the hot tap on and off quickly sometimes this works and the pre heat flashes the led for a period and then the led will go off. This is a pain because you will fill a bath and then realise an hour later your central heating has been off.

graeme, September 2008

Paul

Yes i also had that problem which was solved by replacing the diaphram. I have now solved this problem after much head scratching. It is actually the spring that has lost its tension within the DHW valve and is not returning the spindle to its original location. They do not sell the sping as a spare part(typical) so i had to put the whole DHW valve, about £34. This itself is held in place by a circlip(similar to the micro switch) and the 2 no small pipes,dead easy to replace. This will fix your problem.
cheers

graeme

graeme, October 2008

Hi Graeme. I have the same issue at the moment and I'm considering replacing the diaphram that is part of the actuator that presses the microswitch when the tap is turned on.

If I take the microswitch housing of by undoing the clip to the right of it I can see the actuator rod. If I push this in and then reassemble its fine for a while but then as you say after running tap for a while its broken again. I'll let you know if replacing the diaphram helps.

I replaced it once before last year as I was having an opposite problem where the light would not come on when turning the tap, this was fixed by a new diaphram. I'll let you know.

Paul, October 2008