Thermostatic shower vale plumbing/fault Drainage and wastage systems and plumbing help, advice and answers

[Randy79]

Hi all, new on here but i'm in the process of doing my bathroom and have come up against a problem.

I've plumbed to an external thermostatic shower valve in 15mm copper pipe, with an isolation valve on both hot and cold supplies.
With the hot water pipe matching up with the red spot on the shower valve (no installation instructions for this item) the shower temp control seems to work in reverse. ie warm (not hot) when should be cold and cold when should be 38degrees and past.
This is running off a new codensing combi boiler.

This is the valve that i have:
Google "phoenixwhirlpools.co.uk/pages/products/shower-valves/exposed-thermostatic-valves/luxury-round-exposed-thermostatic-bar-valve-sv008"

I have tried it with the supplies reversed and this gives you cold when cold and hot when hot, but nothing inbetween. You can get it to hot but not regulate it back as it shuts off the cold supply.
I have had the valve replaced but still the same.
Is their anything i can check before i go back to the supplier again?
Is it a plumbing problem?

Any help or thoughts gratefuly recieved.

[plumbbob]

I have tried it with the supplies reversed and this gives you cold when cold and hot when hot, but nothing inbetween. You can get it to hot but not regulate it back as it shuts off the cold supply.

This is exactly how a thermostatic valve will work if the supplies are reversed so your first installation was right.

If you have a problem with temperature, I would investigate the possibility of uneven flow rates between the hot and cold that the mixer is unable to tolerate. Try closing the isolator on the cold input by varying amounts to see how this effects the temperature.

Were any green or yellow discs supplied with the fittings?