Bathroom Fitting

Teeing in a second thermostatic shower to existing pumped shower

Anonymous user 01/03/2024 - 2.50 PM

I have a pumped thermostatic shower in our en-suite, (pump in airing cupboard, fed with 22mm direct supplies from HW cylinder and CW storage tank in loft, then 22mm up through loft to shower). This is brilliant and has worked fine for over a year. Am now refitting the main bathroom, and want to tee off the 22mm (pumped side) pipes just above the airing cupboard to feed a new shower, (as well as the existing en-suite one). After T-ing in and running the new pipes, and simply connecting the new H and C outlets into a T in the new shower area, (with an iso valve on the outlet as a temporary test set-up.) I got pumped H and C through the new outlets, but found the existing shower ran cold... The H water was going through the new pipework as both H and C legs were warm. Removing the T, and simply capping the new H & C separately, and existing shower is back to normal. Question, if I simply connect the new thermostatic shower to the H & C outlets, will both showers run correctly? Or will H or C be able to make their way through the thermostatic mixer of the unused shower (even if this shower is off) and prevent shower being used working properly? (We appreciate we may not be able to run both simultaneously, due to stored water capacity etc. and do not intend to. It will be one or other.)