Output from new thermostatic valve locks on hot and no warm water

diy_massacre · May 26, 2022

Hi

I have a problem with my new concealed shower unit from Bristan, detailed below, I either get to much hot water or cold water but never warm.
"Bristan PM2 SHC3STP C Prism Recessed Thermostatic Dual Control Shower Valve with Two Integral Stopcocks, Chrome, Three Outlet"

Background

Gravity fed system
Electric shower pump
Only connected the bath for now
Previously a 22mm pipework now 15mm thermostatic valve
Cold water pressure very good at ground kitchen sink level
Bathroom pictures in first floor of house.
Instructions of Bristan install followed see attached.

Problem

I either get hot water ( v hot) or cold but no warm despite moving the water temp valve.
If I start at Max cold the bath will deliver cold water whether pump is off or on.
If I start at Max cold turn to hot then back again to max cold the water temp stays very hot, whether pump on or off.

Testing

With water temp set Max Cold turn on the bath tap on and get lots of cold water no issue.
With water temp set Max Hot turn on the bath tap on and get lots of hot water no issue.
With water tap set to Max cold, output cold, then set to medium, the water gets very hot and despite setting to Max cold it never returns to cold.
Both the above tests were done with pump on and pump off configurations and similar results concluded.

Please suggest problem areas?

Basher · May 26, 2022

I think the symptoms are typical of hot and cold transposed.
The whole unit is not on the wall the wrong way up, is it?
Intrigued by the fact the knobs on yours are pointing upwards, but on all the pics on the web they point down.
(I appreciate you can probably put the knobs on pointing any direction!)

The whole unit looks rather symmetrical - I'm afraid I can't see any distinguishing features to tell if the above is just a stupid suggestion!!
PS I now think HOT is marked on the casting, so my suggestion is probably way off!

diy_massacre · May 26, 2022

Basher said:
I think the symptoms are typical of hot and cold transposed.
The whole unit is not on the wall the wrong way up, is it?
Intrigued by the fact the knobs on yours are pointing upwards, but on all the pics on the web they point down.
(I appreciate you can probably put the knobs on pointing any direction!)

The whole unit looks rather symmetrical - I'm afraid I can't see any distinguishing features to tell if the above is just a stupid suggestion!!
PS I now think HOT is marked on the casting, so my suggestion is probably way off!

After checking the face of the knob upwards I think you are correct, there were no distinguishing marks on the body (completely blank) I will turn it around and try again. Many thanks!

Ben-gee · May 26, 2022

It could be easier to switch the output pipes at the pump to see if that makes it work properly.

diy_massacre · May 27, 2022

diy_massacre said:
After checking the face of the knob upwards I think you are correct, there were no distinguishing marks on the body (completely blank) I will turn it around and try again. Many thanks!

Thanks! It took me 10 min to swap it round and it works now, many thanks. sorry to have missed this minor error. Many thanks

diy_massacre · May 27, 2022

Ben-gee said:
It could be easier to switch the output pipes at the pump to see if that makes it work properly.

Many thanks Ben-Gee - thats a good idea! But I turned the tap around, took 10 minutes and it now works, thankyou for your input.

Welcome to PlumbersTalk.net

American Visitor?

Output from new thermostatic valve locks on hot and no warm water

diy_massacre

Attachments

Basher

diy_massacre

Ben-gee

diy_massacre

diy_massacre

Similar plumbing topics