Shower Advice - different pressures

Hi
If the cold gravity supply is ok, how about connecting it to feed the combi?

Balanced pressure, happy days?

Regards
Peter

 

Presumably you've checked the filters on the shower cartridge? Not unknown for crud to get into cold storage tank. (Ref my earlier post!)

 

You need the correct flow restrictions if you want to use an unbalanced supply

 

Pump on the cold supply?

 

Hi Phil.

One of the first things you've said is "Lately my shower has had issues with the cold water..."

Can you confirm that, before 'lately', everything worked fine? In which case it isn't a 'design' or installation fault but that something has changed in your system to cause this imbalance. So I wouldn't be looking to rejig the plumbing or add pumps. But instead try and work out what's gorn wrong.

It could be (a) a slight blockage or alteration carried out to your cold storage tank affecting the cold supply to the shower (is it shared?), or (b) a slight change to your incoming mains pressure affecting the hot supply to the shower, or (c) a faulty mixer cartridge.

The obvious fact is, it worked before, so something has since 'changed'. I wonder what

As said above, you'd normally have both shower feeds coming from the mains with a combi boiler system. But clearly yours hasn't been plumbed that way - tho' it still worked.

What floor are you on, and how far above if the cold storage tank - I'm assuming it's a few floors if it's been working fairly well?

A shower cartridge will need water supplies at roughly the same pressure to operate properly. I'm guessing that, since yours did seem to work ok, your mains pressure ain't that brilliant 'cos you are up a couple of floors, and that your cold stored water pressure is pretty nifty as it's a couple of floors further up?! In other words, your mains might be at less pressure than 'normal' and your stored at higher than 'normal' - so they almost balance out! So, overall, the shower is 'happy'.

(Unless, of course, there is already a pump fitted to your cold supply that's failed?)

Is it the pressure difference wot's caused your shower cartridge to fail? I doubt it. I can't see how it would.

So, I think what I would do is (1) confirm there isn't a pump already fitted on the cold from the tank (I doubt if there is), (2) confirm there isn't a PRV or any other type of adjustment valve fitted on the hot supply to the shower (I doubt that either), (3) try and judge whether the cold supply (from the tank) to your taps is any different to what it was before (turn them fully on and try and remember...) and (4) try and judge whether the hot supply to your other taps is as good as before (turn them on fully and ditto).

If the results of this are 'no', 'nope', 'yup' and 'yep', then I reckon the chances are your cartridge - ie the shower mixer unit - is 'faulty' or needs a clean or replacement.

If you decide to replace the whole shower mixer, then go for a good quality one and also email the manufacturers (or read the specs) providing them with details of your system first and ask if it'll be ok. And/or whether you will need to add any other device as well for pressure balancing.

 

I've had a look at the installation instructions for that mixer you linked to above. It can cope with a huge range of pressures - very impressive - but does suggest (in the troubleshooting section) that the pressures should be fairly balanced.

Before getting one of them, ask the manufacturer. Describe your system in detail.

By the way, what did the plumbers say?