Shower Pump Won't Turn Off

[jezboxley]

Hi,

I recently installed a new 3 bar shower pump on the ground floor of my 4 storey terraced house to feed a new shower room on the 4th floor. The pump is situated within 1 metre of the hot water cylinder on the ground floor and is fed hot water from the cylinder via a surrey flange. The shower pump's cold water feed comes from a roof tank situated above the new shower. Pipework between the pump and the shower / tank / cylinder are continuous lengths of polyethylene (PE-X) barrier pipe and connected with push-fit fittings except where it connects the surrey flange.

The pump works a treat and supplies nice water pressure to the shower in the new bathroom. The problem I have is that 99% of the time it refuses to turn off. When the shower is shut off the pump downstairs begins 'pulsing' as if it is turning itself on and off. At first it appears that the pump has shut off but then the pulsing begins. The only way I have found to turn it off is to gently ease the shower back on and turn it off again very slowly, but this is not guaranteed to work every time.

Does anyone have any ideas what could be causing this? Is it a rush of water back to the pump from the shower that is triggering the pump mechanism again? Would fitting one way check valves prevent this at all?

Any help is appreciated as I have run out of ideas.

Thanks,

Jez

 

[breezer]

pressure switch needs adjusting

 

[chrishutt]

I think you're probably right! The outlets of the shower pump have flow switches. One or both of these is being triggered by oscillations in flow when you shut the shower valve off abruptly.

If you close off the hot and cold inlets to the pump in turn you might be able to determine which is causing the oscillations. It may be that an air pocket in either hot or cold pipes may be causing the oscillations. Are you sure you've cleared all the air from the pipes?

 

[jezboxley]

Thanks for the quick reply guys! I take it the pump will need to be sent back to the manufacturer to adjust the pressure / flow switches? Doesn't appear to be anywhere where I can adjust them.

I think the pipes are clear of air. I let the shower run with the pump turned off for around 10 minutes and then let it run with the pump for a further 10. Some air came out at first but this soon stopped. Is there a better way of clearing possible air pockets?

I shall have a go tomorrow at turning off the inlets in turn to find if there is one at fault. This won't damage the pump in any way by just having one feed running will it?

Cheers guys,

Jez

 

[chrishutt]

It might be better to check the hot and cold flows by putting the shower on it's hottest and coldest settings. If the problem is much worse with one than the other, that narrows it down. If you want the pump manufacturer to check the shower pump, leave it installed and call the manufacturer. They would need to check it installed.