Installing a new Mixer Shower

[Dexman]

I have just had a Combi installed and as a result my current mixer shower is now only pumping out hot water. I have bought a new Thermostatic Mixer to replace my existing one. The measurements seem to be the same and they are both exterior fitting so I assume it is a straight replacement ! Can anyone advise my on how easy this job is ? I believe I have to stop the water supply, open the taps in the kitchen to drain the system and then unscrew the old mixer and put on the new one ! Is it that simple ? Will it effect my new Combi in any way if I empty the water supply ? Do I need to switch it off atall ?

 

[Gees]

Why is your original shower now only producing hot water?
I would investigate this first before ripping it out cos the new one may suffer the same problem.
Its simply a matter of turning off the boiler
open all the taps to drain down
Replace shower
turn on water
Run water through hot and cold taps
Turn on boiler.

 

[corgiman]

probably cos it aint a combi friendly one gees

Follow the above and you will be grand mate

 

[Dexman]

Cheers for your help

It does run hot and cold but then the hot overides the cold.

 

[ChrisR]

Presumably before the combi you had a gravity fed HW system with a HW cylinder? If so you would have had CW fed from the loft tank too. If that's still operating it gives much lower pressure than the hot , so you would get the result you see. If that's correct so far then it's the combi installer's fault. He should have removed the tank in the loft (or left it solely for supplying wc) and conected your bathroom taps CW to the mains. Then MOST shower valves would work.

If he's such a dork then there will be other things wrong too!