Positioning of pipes for a gravity fed power shower All aspects of plumbing questions and answers, help, tips and information

[mweb]

Hi. This is my first post, I've had a look for others but didn't see anything so sorry if this has been covered... I have a cold water (loft) and separate hot water tank (airing cupboard, directly below the cold tank).

One bedroom has an old ensuite thermostatic mixer shower fed from the cold and hot water tanks (gravity only). The pipes run the length of the house in the attic and down into the ensuite.

I'm fitting an Aqualisa power shower in the bathroom (it's a pumped one for gravity systems).

Is it reasonable to supply the Aqualisa by branching off the hot/cold feeds to the ensuite shower?
If I did that is there any benefit to branching out closer to the cold/hot tanks (both showers are the other end of the house) or does it not matter?
Would I need a single/double check valve after the branch for the ensuite to stop the Aqualisa pulling water back from it?
Finally... if I did branch off the ensuite feeds I'd need to take the pipework along then up (equal tee) - evelvation of about 3 inches to take it in to the pump - is that likely to work and again would a single/double check valve help avoid any chance of the Aqualisa having to suck air through at the start of each use?

Thanks for any help and Happy Christmas!

[marrtin]

Power showers use huge amounts of water. Plumbed as you suggest, if the power shower was running, and someone tried to use the ensuite shower, it would very probably work in reverse ie, air would be sucked in through the shower head.

The pump should be placed as close to the cylinder as possible so that they are pumping water not sucking it.

If both showers are thermostatic, why not fit the pump to work both showers?
Ok, if both were used at once, you would obviously notice a reduced flow, but so what?

Plumb as much as possible where both supplies are shared in 22mm.

Check valves reduce performance, and are not necessary