Shower Pump turns on at random

[derekpara]

The new pump on my power shower will come on unexpectedly when the shower is not in use. No water comes from the shower head - I just hear the pump whirring. The only way I can stop it is by switching the electrical supply off then on again or putting the shower on for a few seconds.

Any idea why this is happening and what I can do about it ?

The pump is a dual feed, ie hot and cold supply.

Cheers.

D

[Old_Geezer]

Not familiar, but I'd suspect a pressure sensor having problems.

[AlBags]

There are flow sensors in the power unit normally.
I would think the problem lies with one of those.
Is there enough head on the supplies?

[derekpara]

Well, the pump is next to the hot water cylinder and the cold is off the mains, which isn't very strong upstairs. Following advice from a friend I've fitted a non-return valve on the hot supply, so perhaps I should fit one on the cold. What do you think ?

Thanks.

[AlBags]

I would think one on the hot would cure it ..
What head does the manual say? and does it mention rising/pressure supplies?

[derekpara]

Thanks, AlBags. The valve on the hot supply hasn't made any difference.

This pump is a replacement for similar one that worked perfectly for years.

I'll check the manual, but it was fitted by a professional (friend) who is coming to fit a non-return valve on the cold supply in the next few days.

Cheers.