PEV / PRV & Twin Impeller

4 Aug 2012
Reaction score
Tyne and Wear
United Kingdom
Hi all,

Just looking for a little advice!

I'm in the middle of fitting a power shower..

Cold is mains fed and hot is to be pumped due to low pressure..

The problem is, I'm stuck with a twin impeller pump, and I know cold mains should never be pumped directly (bought it a while ago, just got round to fitting shower)

Would it be ok to run the cold mains through a pressure reducing valve before going into the pump, or possibly run both hot and cold through a pressure equalising valve before the pump? And then outlets of the pump to the shower mixer

Or: Run HW on both sides of the pump (so it doesn't run dry on C/W side), and run C/W straight to mixer (through prv)

Or: Bite the bullet and buy a single impeller for H/W, with c/w straight to mixer (through prv)

Any help would be much appreciated

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Run a cold feed from the tank to the pump.

I'm not quite sure that the tank is big enough, I think the tank would probably empty quicker than it could fill while feeding the cold water side of the mixer as well as the water heater. Fitting a bigger water tank wouldn't be an option either :(
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Why do people come on here for advice, then promptly ignore sound advice from a professional?
I get it day in, day out from counterboys who ring for advice, then go on to contradict me with crap ideas that wouldn't work in a million years.
Sadly, the counterboys are 'professionals'.
Well, thanks for the warm welcome, but I was simply providing more details of my situation, like I don't think the C/W tank would be big enough, and that I already have the leading pipe work and mixer fitted.. I provided this is as a prompt to see if anyone had an alternative solution to best fit my situation

I do genuinely appreciate the replies but there's no need to get hostile
Not being hostile in the least. Merely stating a truth.

Either bodge you town pump to dual hot use and reduce your mains pressure.

Or do it properly and feed the shower from the cold tank. That might require adding more cold water storage.

No one is going to sanction a fact idea like sticking mains water through what is likely to be a cheap plastic shower pump.

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