Plumbing in shower pump to existing pipework

[bucksdecor]

I'm sure this will have been covered but I cant find the answer.
I want to put a twin 1.5 bar shower pump feed in. Due to difficulty running new pipes from cylinder. Could I tee off before the first services (ie sink then bath). I am aware there would be a danger of air being drawn back, so is it possible to fit a directional flow valve after the tee to the pump and before the sink to solve this possible problem

 

[Cpplumber]

This would hopefully prevent air being drawn back if someone opened a basin tap as you suggest.

The problem lies with air being drawn in from the configuration prior to this. The design of the hot water cylinder is that air and micro bubbles would find their way up the vent pipe and some inevitably would find its way down the hot water service Pipework. I would always suggest following manufacturers guidance and most specify a flange or suitable connection to de-aerate the water before the pump gets involved. Some manufacturers don't specify anything however, but always try and follow as best you can or you stand no chance with a warranty.

In the absence of anything instructions I favour a surrey flange to protect the pump from air. I can appreciate you say you can't run additional Pipework but air in a pump can be pricey...

you could always consider putting the pump in the airing cupboard and boosting both hot and cold supplies to the bathroom in question to benefit from increased flow to your bath as well if you have one?

 

[bucksdecor]

That's a good idea. Being 1.5 bar would it be ok to run it thru the mixer taps on the sink and bath. not to savage?