Thermostatic Mixer Advice

[alfa20ad]

Hello. Currently in the process of changing an electric shower into a thermostatic mixer shower, its a bit of a long story with the builder but the existing shower area was basically bodged in to fit and tiled over concealing a few of the builders hacks into the plasterboard walls and getting the bottom tray to fit, its been a bit of a PITA.

I have stripped this area back to the stud partitions and will be installing a thermostatic mixer shower. I have the existing cold feed already in place and will need to lift flooring to fit the hot feed, will install again in 15mm speedfit.

The question i ask is what parts do i need to purchase in order to secure the pipes firmly behind the stud wall in order to fit the mixer bar. Also do i need to fit non return valves to the hot and cold water feeds?

 

[Ben-gee]

So you have a mains cold feed, how is your hot water supplied? If it’s unvented cylinder or Combi boiler then crack on, if you have gravity hot then wait for further advice.

If you are using a bar mixer valve then you can bring plain pipe out at 150 centres and secure the valve using a front fixing kit ( this is the easiest method). Put a piece of 18mm ply flush to the front of your studwork and drill 20mm maximum holes for your pipes, then you’ll have something to screw into.
Finish wall (tiles/ boarding) then drill right through this finish but not through the ply and attach fittings with stainless steel wood screws - it will never move and you could hang from it should you so wish.

As you’re using plastic pipe clip it to the studwork to stop it banging around when the valve is shut off.

The valve should have non/return valves built in at the hot/cold connections.

 

[alfa20ad]

So you have a mains cold feed, how is your hot water supplied? If it’s unvented cylinder or Combi boiler then crack on, if you have gravity hot then wait for further advice.

If you are using a bar mixer valve then you can bring plain pipe out at 150 centres and secure the valve using a front fixing kit ( this is the easiest method). Put a piece of 18mm ply flush to the front of your studwork and drill 20mm maximum holes for your pipes, then you’ll have something to screw into.
Finish wall (tiles/ boarding) then drill right through this finish but not through the ply and attach fittings with stainless steel wood screws - it will never move and you could hang from it should you so wish.

As you’re using plastic pipe clip it to the studwork to stop it banging around when the valve is shut off.

The valve should have non/return valves built in at the hot/cold connections.

The system is on a Combi boiler, was thinking of half copper using the Marflow PL8 and then fixing the speedfit onto the copper work which would give a nice sturdy fix. Does this sound alright?

 

[Darren Jackson]

As Ben-Gee quite rightly points out it is important to know if you have a high or low pressure hot water system. As the the hot & cold feeds need to be balanced.

 

[alfa20ad]

As Ben-Gee quite rightly points out it is important to know if you have a high or low pressure hot water system. As the the hot & cold feeds need to be balanced.

The system operates just over 1 bar. The boiler is fed direct from mains pressure. The bath tap is also a thermostatic mixer tap and the feed for the shower would come directly off this.

 

[Ben-gee]

Yes that sounds fine.

 

[alfa20ad]

Yes that sounds fine.

So just to clarify... im good to go on this?

Also what about the PL8 bracket, do you guys think this is a sturdy fix to studwork using copper pipe as droppers and using speedfit to connect to the 15mm PEX barrier pipe at the bottom. Copper Pipe will also protrude through tiles obviously.

 

[Ben-gee]

I suspect it will be good, I happen to prefer my ply method because I will do all of the hidden work in bent/soldered copper which I trust and do in fact guarantee. And in my opinion you can’t get a better fixing than a screw into face of ply, or sturdy timber.

 

[king of pipes]

Yes you are good to go i have used this bracket i would advise you use 15mm copper pipe and adapt to speed fit where appropriate ,well bracketed pipework is a must ,balanced supplies , isolation valves accessible of course, one other thing i would say is fix the plate to a piece of ply set it back in the stud work at least by 25mm before any boarding is fixed and test the first fix before hand best of luck. kop

 

[alfa20ad]

Thanks for your help guys most appreciated.