What's wrong with my boiler? (PigletJohn?)

[Selks]

Anyone have an idea what is going on with my boiler...

It's a Baxi combi boiler, about eight years old, always been dead reliable.
However the hot water is now not working unless the heating is on. Heating on - hot water no problem. Heating off - water runs cold and boiler does not fire up. Heating seems to be working fine, although the radiators do seem hotter than usual. Thermostat problem??

Any ideas? I've got someone coming out tomorrow (hopefully) but wondered if anyone in the know had any ideas in the mean time.

No answers I'm afraid, but much sympathy, mine is currently doing the opposite - if you turn the hot water on, the radiators warm up - we had a plumber out who said it was a valve that needed replacing and probably not worth paying for because the boiler is getting on a bit

Thanks Toomuch. Sorry to hear about your boiler.

I think it might be the flow switch, that detects you have a hot water tap running. Sometimes they work if you have a hot bath tap gushing but not if a basin tap is trickling.

Too much rain, I suppose it is the diverter valve in a combi. If you had a cylinder, the 3 port switch is outside the boiler and an easy plumbing job to change. Are you sure he doesn't just want the more profitable business of selling you a new boiler?

Hi Piglet, thank you for that. Is it an expensive thing to fix, would you say?

I wouldn't have thought so, unless the maker has designed it to be difficult to get at

of course I might be wrong about the cause.

Cheers Piglet. The power of Google seems to confirm what you're saying. Plumber yet to get here but soon hopefully.

if its a baxi combi 80e (series of red lights that illuminate as the boiler gets hotter?) then i would say 90% its the hw flow switch as PJ already said. Its an easy job for any competant engineer on this model. Which area are you in?

I think you might be right pigletjohn, we are getting a second opinion on it later this week, thanks

NW, Salty. Are you a plumber?

Im a gas engineer. London based though

Cool. Thanks for your input