Shower booster pump installation (boost all outlets)

1 Jul 2014
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United Kingdom
hi, have a indirect hot water cylinder with hot and cold both fed from a 80 gallon cold water tank.

Have recently fitted a thermostatic bath shower mixer tap as didn't want to chase walls/remove tiles to fit a dedicated shower. Both has poor flow plus the flow to basin tap is generally poor which I'm guessing is due to a gravity fed system.

Planning on fitting a salamander 2bar twin negative head booster pump in airing cupboard.

I want it to boost all outlets in my house.

Would it be ok to fit a Surrey flange on the hot and run 22mm to pump as the hot suppy l, and where the old hot draw off on top of the cylinder tees off for the hot supplies cap that part of then connect the outlet of the boosted hot back into the hot water circuit?

For the cold it is ok the find the cold down services from the cold water tank cut into it and fit an elbow into the pump and again fit the boosted cold back into the other side of the cold pipework? Wouldn't have thought I'd need a dedicated suppy as I'm boosting all outlets and not just the shower?

Do I need to fit non return valves on the other side of the pump or will they all ready be built into the pump?

And finally, is it worth fitting a AAV on the inlet to both hot and cold supplies feeding pump to help with any air issues?

Thanks in advance for your help/advice.

My skill set for plumbing is pretty good, so far I've fitted my own bathroom and replaced hot water cylinder in my old house.
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If you're looking for a whole house (do you really need it downstairs?) one of the ST Monsoon pumps, at least 3 bar, would be my recommendation.
Yes, use a surrey flange but don't cap off the vent going up to the attic/cold cistern, the cylinder needs that as part of its safety features, cap the hot supply just after the T to the vent, on the distribution pipe.
Check what cold outlets are tank fed. You will have at least one cold mains fed tap, usually the kitchen sink, do you need any more?
No reason you can't use the current water circuit as both the dedicated feed and distribution circuit for the cold and distribution for the hot. How sound is the current pipework, it's been dealing with low pressure up till now, is it sound enough to take mid to high pressure?
No valves in between the feeds and pump apart from the supplied ISO valves on the flexi's. Both tank fed so no need for check valves.

All that being said, you need to apply a bit of thought and design the system accordingly. Negative pump? Have you pipework at the level or above the cold cistern? Height to the hot cylinder? Take into account - toilet, if it gets used at 3am do you want the pump firing up? Do you really want the pump firing up any other time water is being used? Do all outlets really need pumped? If the pump fails, how big an impact...etc. Just a few things I'd crossoff.
If you are worried regarding the pump making a noise at 3am when someone uses the toilet, you can plug the pump into a timer so that it only works between 6.30am to 11pm.

The toilet would still refill.


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