water heating problem

[nitsypee]

Hoping you guys might be able to help with this.

My combi boiler (Alpha HE CB25) seems to be erratically heating my water: when I turn on the hot tap, unless I turn the tap to full power the boiler usually won't heat the water. When I'm using the shower it's the same, and sometimes it just turns off the heat completely, leaving me in a freezing shower.

Speaking to my local plumber, he reckons it's "probably" the diverter valve, though he admitted he couldn't guarantee it. For putting in a new one, including labour, it will be around £500.

This seems a lot of money to pay for something that will "probably" fix the problem.

Any thoughts?

[nitsypee]

Just giving it another trial, I think I was wrong to state that it was "erratic". It's pretty much every time - the water is only heated if the tap/shower is on full power/turn. Otherwise the boiler shuts off, and you get freezing cold water.

Is my boiler clogged up?

[Arthur Jackson]

Assuming it uses a pressure drop diaphragm to sense the tap it sounds like it has a split in the diaphragm which needs the tap flat out to give enough drop to operate the diverter and microswitch. Probably a £20 rubber diaphragm.
HOWEVER, I'm no boiler man and some combis work in other ways.

[xllifts]

We had the very same trouble with the very same boiler. It is usually the seal/flange thing in the divertor but to save fiddling round trying to seat them properly etc we just change the whole diverter valve assembly. Cost £100 from plumbbase and did it ourselves in about three hours, took longer to drain and refill the system than changing the part.

[eskidavies]

500 notes fking rip off hes making 400 quid labour for an hours job a new valve is 100 a repair kit about 20-30 taking the piss

[dirkgently]

eskidavies said:

500 notes fking rip off hes making 400 quid labour for an hours job a new valve is 100 a repair kit about 20-30 taking the piss

A Diverter valve for the alpha is towards the top end of £200, then there is the misery of working on the damned thing, (which wont have been touched since it last broke down)and then hopeing that nothing breaks, leaks or otherwise goes wrong before you get paid.

[Deva Link]

Don't British Gas have a fixed fee repair service that would be lower even than that £200 parts cost?

[Arthur Jackson]

dirkgently said:

....then there is the misery of working on the damned thing,

Cheap combi boilers make me think of this.....