What size pipe for thermostatic shower?

[bazza1410]

Hi, I am undertaking a bathroom refit which involves replacing a bath with a walk in shower. The hot and cold feed pipes going to the bath are 22mm and I was wondering if I can use this feed for a thermostatic shower or will I need to reduce down to 15mm? Do you get showers that are 15mm and 22mm? It's a system boiler if that makes a difference. Thanks.

 

[JCplumb]

You'll need to reduce to 15mm for the shower. If it's gravity hot water you're going to struggle with a mixer shower unless you get a pump but that brings its own problems.

 

[bazza1410]

Should I just stick to an electric shower then? Do you think it definitely would not work?

 

[bazza1410]

Should I just stick to an electric shower then? Do you think it definitely would not work?

could it be possible there is already a pump fitted as the en-suite shower is a mixer shower?

 

[PlumbBobBob]

when you use the ensuite shower can you hear a pump going at all?

 

[bazza1410]

I've never noticed before but I will give it a listen. Are they fairly easy to install because if a pump is the way to go I would rather install one.

 

[PlumbBobBob]

if you haven't noticed it running chances are you haven't got one tbf

 

[bazza1410]

The current set-up was fine for the bath will it really make a big difference to the shower. I would only be extending the pipes by a couple extra feet with that really make that much of a difference to the pressure

 

[Plumbstar Tom]

gravity showers are never very good unless pumped IMHO

 

[bazza1410]

I don't think I would fancy fitting the pump myself. If I supplied the pump does anybody have a rough idea how much a local plumber would take to install it?

 

[JCplumb]

Without eyes on the job, my advice would be that the easiest option is likely to be an electric shower, if you want a good strong shower you'll be looking at a higher rating than 8.5kw, make sure you choose the shower before the sparky runs the cables for it and let him know the rating.
If you're on a gravity system with or without a pump and you already have an en suite shower you could be looking at the water running out if both showers are used at the same time. You are limited by the amount of stored hot water you have and the size of the cylinder header tank which may need to be upsized bringing logistical problems re loft access, strength of base etc.
If a pump is used and you don't already have one - a surrey / essex flange would need to be installed on your cylinder.
Nine times out of ten the easiest solution is run some cabling and bung an electric shower in, unless you're thinking of changing your water systen to a combi or unvented system.

 

[bazza1410]

Ok thanks for your advice. There are only two people in the house (my parents) so i dont think running out of water would be an issue, but having poor pressure would! The wiring and plumbing are already there for electric shower as we had one above the old bath. They just dont look as good imo.

 

[Radioman]

Having done this expertise for all the OAP's in my immediate and distant family I would avoid an electric shower, they are never as good as a proper digital shower. To make it as safe as possible you will need to replace all the wiring to code, possible meaning a new consumer unit, and even then the life span of the shower is limited, especially in hard water areas unless a water softener is installed . Trust me you want complete reliability and a good shower. Fit and forget solution is an Aqualisa Digital, sourced on line, easy install, 5 year warranty.

 

[bazza1410]

Thanks for your input but the problem I have is the low pressure from a gravity fed system. Is the shower you are talking about electric?

 

[kris]

A mixer will work good depending on head of pressure as i used to have a gravity shower on groundfloor , hw on first and big cwsc in loft. it was always great gravity pressure because of heights and the pipes were ran properly with least bends as poss and they were all formed bends, your problem youll have is your bath will be cold water main is it ?
and your hot gravity so wont be balanced, Me personally i hate lecky showers as poor flows but sometimes needs must ,

 

[bazza1410]

Now looking at getting combi boiler as current one is 20 years old and that would fix all problems. Who would have thot getting a decent shower could be such a pain!

 

[kris]

True enough bazza