Problematic thermostatic mixer shower

[Jimmy McMahon]

Hi all,

I hope you are well.

We bought our first property in the middle of last year and as such, this has been my one of my first experiences of having to do anything remotely DIY related (we have previously lived in rented properties where the landlord sorted out the DIY, via their contacts). The property has 3 showers (Triton thermostatic mixer showers), all fed from an Ideal Instinct 24 combi boiler.

2 of the showers work absolutely fine.

The shower in the main bathroom however does not maintain its temperature when the temperature handle is stationary. The water either runs red hot or freezing cold with intermittent blasts of "warm" water in-between. Moving the temperature handle does not result in the expected outcome (i.e moving the temperature handle to hot does not necessarily make the water hotter. The water temperature that is output seems to be random).

I had a read online and the suggestion was to replace the thermostatic valve in the bar, which I did earlier in the week, to no avail. The temperature does not remain "shower friendly" for long enough. The issue with the temperature not going up or down consistently when the handle is moved still remains.

One thing I have noticed is that when I touch the left hand side of the bar, it is cold and the right hand side of the bar is hot. This suggests that the shower has been piped up the wrong way around doesn't it? Could this be attributing to the problem?

I was going to just buy a completely new shower bar and see if this improves things, however I am a little confused as to why replacing the thermostatic valve with a new one had no real impact on the issue. Does this suggest there is another issue here?

If I do buy a new shower bar, would there be any issues in me installing it upside down to accommodate the pipes being the wrong way around? (I know the real answer is to get the pipes plumbed the right way round, but I am looking for a temporary fix for now which will allow the shower to be used).

Any advice would be much appreciated

I was going to go and buy a new shower bar later today, but I would be interested in your views around whether that would be a waste of money based on the scenario described above.

Many thanks in advance
Jimmy

 

[Rob Foster]

Hi all,

I hope you are well.

We bought our first property in the middle of last year and as such, this has been my one of my first experiences of having to do anything remotely DIY related (we have previously lived in rented properties where the landlord sorted out the DIY, via their contacts). The property has 3 showers (Triton thermostatic mixer showers), all fed from an Ideal Instinct 24 combi boiler.

2 of the showers work absolutely fine.

The shower in the main bathroom however does not maintain its temperature when the temperature handle is stationary. The water either runs red hot or freezing cold with intermittent blasts of "warm" water in-between. Moving the temperature handle does not result in the expected outcome (i.e moving the temperature handle to hot does not necessarily make the water hotter. The water temperature that is output seems to be random).

I had a read online and the suggestion was to replace the thermostatic valve in the bar, which I did earlier in the week, to no avail. The temperature does not remain "shower friendly" for long enough. The issue with the temperature not going up or down consistently when the handle is moved still remains.

One thing I have noticed is that when I touch the left hand side of the bar, it is cold and the right hand side of the bar is hot. This suggests that the shower has been piped up the wrong way around doesn't it? Could this be attributing to the problem?

I was going to just buy a completely new shower bar and see if this improves things, however I am a little confused as to why replacing the thermostatic valve with a new one had no real impact on the issue. Does this suggest there is another issue here?

If I do buy a new shower bar, would there be any issues in me installing it upside down to accommodate the pipes being the wrong way around? (I know the real answer is to get the pipes plumbed the right way round, but I am looking for a temporary fix for now which will allow the shower to be used).

Any advice would be much appreciated

I was going to go and buy a new shower bar later today, but I would be interested in your views around whether that would be a waste of money based on the scenario described above.

Many thanks in advance
Jimmy

Your in the right place , most of the experts are out on patrol, so wait and see, I am a Ch engineer, so cannot really help
Centralheatking

 

[Chuck]

The symptoms you describe are those that occur when the hot and cold supplies have been swapped. Traditionally, the hot supply is on the left and the cold supply is on the right. This convention applies to taps on basins, etc. and needs to be adhered to for safety reasons. (People are in the habit of expecting the RH tap to be cold and can accidentally scald themselves if this is not the case.) I mention this because you need to check that when you swap the supplies to the shower you don't reverse the supplies to basins/baths as a side-effect.

I've never tried fitting one upside down. I'd expect it to work as a short-term test but I'd want to check the manufacturer's instructions (or by phone) before doing it permanently. There may be some non-obvious legionella risk if it's the wrong way up, for example.

 

[Jimmy McMahon]

Thanks for your replies.

As a temporary fix do you see any point in my buying a new shower bar and just installing it upside down (which I expect is how the current bar has been installed to get around the pipes being the wrong way around) ?

Or am I barking up the completely wrong tree here ? I am still dubious as to why the new thermostatic valve replacement had no effect.

Cheers

 

[Chuck]

I am still dubious as to why the new thermostatic valve replacement had no effect.

When correctly installed, the thermostat responds to 'too cold' by closing the RH port and opening the LH port, which maintains the current state. If the pipes are reversed this 'negative feedback' action becomes 'positive feedback', which will tend to flip to either fully cold or fully hot. It will be possible by fiddling with the lever to get the shower into a 'warm' state but this will be 'metastable' and will soon degenerate into fully cold or fully hot unless you intervene by constantly tweaking the lever.

There was nothing wrong with the first thermostat, other than being incorrectly piped, so replacing it made no difference.

 

[Riley]

Why would the thermostatic cartridge being replaced have any impact if its piped wrong ??

 

[Rob Foster]

Why would the thermostatic cartridge being replaced have any impact if its piped wrong ??

Because one might try it just to see, I am often upside down as you all know ...paloma faith is good at fitting thermo showers...she has been upside down and made a fortune
Rob Foster aka centralheatking

 

[ShaunCorbs]

You can flip it but don't forget everything will be backwards on the controls if you happy with that flip it

 

[Rob Foster]

You can flip it but don't forget everything will be backwards on the controls if you happy with that flip it

but if you look in a mirror when operating it all will be ok !

 

[Welder]

You can flip it but don't forget everything will be backwards on the controls if you happy with that flip it

Shauns correct, but personally I'd get the supplies swapped over elsewhere and keep what you have.

 

[Rob Foster]

Shauns correct, but personally I'd get the supplies swapped over elsewhere and keep what you have.

Spot on advice in my opinion
Rob Foster ...chk

 

[Jimmy McMahon]

Thank you everybody.

When correctly installed, the thermostat responds to 'too cold' by closing the RH port and opening the LH port, which maintains the current state. If the pipes are reversed this 'negative feedback' action becomes 'positive feedback', which will tend to flip to either fully cold or fully hot. It will be possible by fiddling with the lever to get the shower into a 'warm' state but this will be 'metastable' and will soon degenerate into fully cold or fully hot unless you intervene by constantly tweaking the lever.

There was nothing wrong with the first thermostat, other than being incorrectly piped, so replacing it made no difference.

Hi Chuck.

Thanks for the reply.

*Probably silly question alert*
If I was to go with the workaround of turning the shower bar upside down so that the hot and cold are going in to the correct sides of the bar, would I need to swap the postion of the thermostat to the other side of the bar or does it not matter which side it is on physically (i.e will it still respond to too hot or too cold the same way you described even though it would physically be on the opposite side of the bar / pipes?)

Cheers

 

[Chuck]

This poses the question around if I was to go with the workaround of turning the shower bar upside down so that the hot and cold are going in the correct sides of the bar, would I need to swap the postion of the thermostat to the other side of the bar or does it not matter which side it is on physically (i.e will it still respond to too hot or too cold the same way you described even though it would physically be on the opposite side of the bar / pipes?)

I don't understand why you are confused, which may mean I've missed something. I'm assuming that you can just rotate the whole assembly by 180° in the plane of the wall. So, the outlet port will move from bottom to top, HW inlet port from left to right, and CW inlet port from right to left. As a result HW will flow into the HW port and CW will flow into the CW port.

 

[Riley]

If you swap the thermostatic valve across then you’re in the same position. It’s the position of the valve compared to the hot and cold that makes it work

 

[Jimmy McMahon]

Hi Chuck, I completely understand the turning the whole bar upside down methodology. The question was more around the physical location of the thermostatic valve (as you mentioned about when setup correctly that the RH and LH valves are closed off or opened depending on the too hot / too cold scenarios).

As of right now, the thermostatic valve is on the right hand side of the bar (physically).

When I unscrew the bar and flip it, the thermostatic valve will then physically be on the left hand side and the on / off control on the right hand side.

Does this make any difference, or will the thermostatic valve still operate in the way you mentioned?

I suppose I am looking for confirmation as to whether this statement is true or not :-

"The physical location of the thermostatic valve is irrelevant and it will operate exactly the same way if the bar is piped in correctly (hot - left, cold - right)"

Cheers

 

[Riley]

Most if not all thermostatic bar showers have a specific hot and cold side. If piped wrong they don’t work. That’s it end of!

Rather than flipping it upside down get the piping fixed

 

[Jimmy McMahon]

Hi Riley, to get the piping fixed, I would assume mean knocking through the tiles behind the shower to correct it? Or can it be corrected elsewhere?
If the first option, then I am happy with the workaround as long as it works. The bathroom it is in will only be used by guests when they come to stay.

Cheers

 

[Riley]

Do the pipes run down in the wall or up? Is it a shower over a bath?? There could be the possibility of going through the wall on the other side and patching it. Much easier. I really wouldn’t be working around

 

[Jimmy McMahon]

added in error

 

[Riley]

You are but we can’t vouch for how this will affect overall performance or warranties.

 

[Jimmy McMahon]

Hi Chuck, I completely understand the turning the whole bar upside down methodology. The question was more around the physical location of the thermostatic valve (as you mentioned about when setup correctly that the RH and LH valves are closed off or opened depending on the too hot / too cold scenarios).

As of right now, the thermostatic valve is on the right hand side of the bar (physically).

When I unscrew the bar and flip it, the thermostatic valve will then physically be on the left hand side and the on / off control on the right hand side.

Does this make any difference, or will the thermostatic valve still operate in the way you mentioned?

I suppose I am looking for confirmation as to whether this statement is true or not :-

"The physical location of the thermostatic valve is irrelevant and it will operate exactly the same way if the bar is piped in correctly (hot - left, cold - right)"

Cheers

I think I have just worked this out in my head haha.

In a correct setup, the thermostatic valve would be on the right hand side of the bar (next to the cold water pipe).

My current setup has the thermostatic valve next to the hot water pipe due to the incorrect piping.

By flipping the shower bar I am essentially moving the thermostatic valve next to the cold water pipe in my setup, replicating a "correct" setup.

 

[Jimmy McMahon]

You are but we can’t vouch for how this will affect overall performance or warranties.

Thanks Riley. I know the permanent solution is to get the pipes sorted. I can confirm I have just flipped the bar upside down and the shower now actually works as expected. This should see me over the Christmas period when we have people visiting and then I can potentially look at a more permanent solution after Christmas.

Thanks for everyone's help and all the very best for the New Year.

Cheers
Jimmy