Shower Pump with Non-Return Valve

[PhilD2]

Hello
The instructions on my pump say "Do not install a non-return valve or devices which contain non-return valves in the suction (inlet) pipework to the pump. The pump must be free to vent to the supply tanks at all times".

My pump is fitted between the shower mixer and the shower head but I do have a non-return valve fitted on the hot feed to the shower mixer - does this still count as being in the inlet pipework? If so could this be the reason why my pump sometimes fails to cut in? If I remove the non-return valve then my overflow pipe starts spurting out water continuously. Is this anything to do with the pressures being different for the hot and cold feed to the shower?

Any help anyone could offer would be greatly appreciated.

This topic gives more detail.

//www.diynot.com/forums/viewtopic.php?p=768665#768665


Thanks
Phil

 

[seco services]

read your last post why has your cold got more pressure than the hot ?
it is fed from the cws tank in loft or from mains water supply ?

 

[PhilD2]

Hi
The cold is fed from the cws tank directly to the shower.

To be honest I'm assuming it is greater pressure but thinking about it I'm basing that on the hot and cold feed to the bathroom sink where the cold is substantially more powerful but in that instance the cold is mains fed so that is not a sensible comparison.

It may be that they are the same pressure.

Sorry to be so vague but this is all a minefield to me.

Thanks
Phil

 

[PhilD2]

Hi
It now doesn't seem to be cutting in at all. I had a shower yesterday afternoon and a day later it still isn't cutting in. Previously it would generally be a couple of hours or so after having a shower until it would cut in again.

Cheers
Phil

 

[Breesey]

You need balanced, dedicated feeds and the pump should come before the shower mixer.

 

[PhilD2]

Hi
It's a single impeller pump, I understood that single impellers came after the shower mixer.

 

[Breesey]

Oh right!!