Shower Pump starting on its own

[TheMrX]

Well not exactly on its own....Sometimes if you turn the hot water tap on/off in the kitchen or bathroom, there will be a short (0.5 sec) burst of the shower pump coming into life. No water is expelled from the shower but the pump makes a noise as if the shower has been turned on momentarily.

I'm guessing its some sort of airlock in the hot water system but how do I resolve it?

It's wierd that it seems to come and go. Will be okay for a few days then will do it for a few days before stopping again.

I've tried to backflush the hot water supply from the mains and that appears to fix it (for a while) but nothing permanent. Is there some sort of valve I can fit before the pump to stabilise the pressure after it so it isnt affected by the other hot taps being used?

Any help appreciated.

 

[Parkymike]

The pump has switches that sense water flowing past them.When you are turning on your taps the pressure in the pipework drops.When the tap is turned off the pressure builds again and there must be a slight movement of water in the pipe passing the switch.Have you had the water off and not quite turned on the isolation tap or fitted a tap with a greater flow.

 

[TheMrX]

No, not done anything with the plumbing at all.

 

[Parkymike]

Maybe swithes are just getting tired then.

 

[TheMrX]

So would that mean a new pump?

Or could I reduce the flow slightly to the other hot taps?

 

[tamz]

So would that mean a new pump?

No. Just flow switch.

 

[picasso]

do you know which kind of pump you have, ?(positive or negative head)

 

[TheMrX]

I'm not sure.

The pump is on the floor, at the same level as the base of the hot water cylinder. The cold storage tank is in the loft above.

So I'm not sure whether that makes it positive or negative?

 

[tamz]

I'm not sure whether that makes it positive or negative?

Positive