My power shower again..working intermittently, why?

[littlewren]

Following on from the problem of my power shower suddenly not working......four days ago, I decided to switch it on in the airing cupboard just to see if it now worked, and it did. Great, I thought, whatever it was has fixed itself. Two hours later, my daughter went to use it and it wouldn't work again.

Two days passed and I decided to try again yesterday. It worked, then an hour later it wouldn't.

Has anyone any new ideas as to what it could be that's making it work intermittently like this? It still makes a little noise when I put the switch on in the airing cupboard, I don't know if this is a clue but it has done this for a long time.

Surely it now can't be the pump?

Any help would be gratefully received as I'm still loathe to call anyone out until I have more of an idea as to what could be wrong.

Many thanks,

Carrie :)

[Ian Stirling]

Some designs of pump can suffer from metastability, when instead of it properly starting, it sits there and hums.

This can especially happen when it wears.

[Ed Sirett]

One of the failure modes of booster pumps is that the magnetic float which activates the pump corrodes (despite being encased in plastic) and swells up. The float has a way of half jamming in the pipe and so failing to start the pump.

This may or may not be the case hear it might also be compounded by the action of a themrostatic mixer (which when it cools shift to 100% hot say but not when it's still warm). This may or may not be the case here.

[littlewren]

Thanks for your messages Ian and Ed.

So Ed, it could just be that it needs one of these new floats? Would an electrician be able to have a look at the problem, only I know a reliable one and I don't know any plumbers and am scared of being ripped off. :(

Thanks very much,

Carrie