Water Pressure with mixer valve/combi

[colmar]

I'm in the process of refurbishing my bathroom. I'll be replacing the existing bath with a walk in shower. Will be installing a thermostatic mixer valve fed by mains on the cold side and a combi boiler (Logic Combi c30) for thr hot.

Ideally what I'd like to do is have the mixer valve at the entrance to the walk in showervand the shower head at the other end. I have to raise the shower tray anyway to accommodate the waste into a communal pipe. This provides an opportunity to take the mixed water pipe from the mixer valve under the tray and then back up to the shower head. I've not measured it precisely but this would mean a pipe run from the top of the valve to the shower head of somewhere between 4 and 5 metres.

So the question is this. Should I expect a pressure drop at the shower head compared to the mixed water pressure coming out the top of the valve. If so how would I measure that drop without actually running all the pipework I.e is there some kind of mathematical equation for this scenario. Or would I get the sane pressure at both ends with the combi boiler pump doing the work for me?

 

[Timmy D]

The boiler doesn’t have a pump on the hot water.

Your plan is fine, I’ve done it plenty of times and is my preferred method. I bury the pipe in the wall rather than under the tray.

Here’s a couple I’ve done.

Ceiling outlet…

 

[colmar]

Nice work. I'm going to be using the new fangled waterproof shower panels so it's more important than ever to get it right as I don't want to be ripping them off when the shower ain't working the way I want. Expensive mistake!!! They're not cheap but are more or less seamless and easier to maintain. No grout to discolour. Didn't realise there's no pump for hot out of the boiler. Learn something new every day.

I've more or less decided that the best way to do this is to 'mock it up' before I put the tray in or wall finishes on just to see what the performance would be like in either scenario. I've actually installed a not dissimilar arrangement for a client several years ago and really did it without much thought and, like you I buried the mixed hot/cold in the wall.

Thanks for thr input

 

[colmar]

Thanks. I'll try to find a hard copy as I havnt got a kindle