Problem with a thermostatic shower

[Rodolphe]

I was called to replace a leaking thermostatic shower. The client elected to buy a whole new tap, the same model as the previous one, which was only 4 years old.

Upon dismantling the old one, I noticed the hot and cold pipes were inverted. I mounted the new shower as the old one was (i.e. cold/hot are inverted).

The shower won't stop playing up. It doesn't maintain a constant temperature, instead heats up until almost scalding. It will tend to cut off cold water flow altogether, although sometimes will do the same thing to the hot.

Although the shower is brand new, I am thinking that the new cartridge is faulty. However, can the fact that the pipes are inverted have an effect that I am too stupid to recognise? After all the old shower was mounted in exactly the same way as the new one is...

Thanks in advance for your advice.

 

[chris watkins]

I was called to replace a leaking thermostatic shower. The client elected to buy a whole new tap, the same model as the previous one, which was only 4 years old.

Upon dismantling the old one, I noticed the hot and cold pipes were inverted. I mounted the new shower as the old one was (i.e. cold/hot are inverted).

The shower won't stop playing up. It doesn't maintain a constant temperature, instead heats up until almost scalding. It will tend to cut off cold water flow altogether, although sometimes will do the same thing to the hot.

Although the shower is brand new, I am thinking that the new cartridge is faulty. However, can the fact that the pipes are inverted have an effect that I am too stupid to recognise? After all the old shower was mounted in exactly the same way as the new one is...

Thanks in advance for your advice.

You don't want me to answer the last bit of the question do you ? If it states that the hot should be on the left & cold on the right then that's what it should be. The mixed water passes over a thermostatic file which expands or contracts depending if it is getting too hot or cold, this movement is used to change the mix of water. So lets say the water coming out of the shower head is getting to hot the sensor file expands & that causes the hot to be shut down a little (& normally the cold to be increased at the same time) restoring the correct temperature, but of course in your installation instead of the hot being closed, it is the cold !!! It can't operated correctly if piped up the wrong way around.
Hope that helps ?
BTW some shower valves have two outlets so can appear to be installed upside down if the other outlet on the other side has been used.

 

[Rodolphe]

Well, I feel like a muppet now, but at least I learn something every day.

Thanks Chris.

 

[chris watkins]

No probs, you wont do that again will you !!
PS always check problem showers by moving temp level fully cold direction & it should go cold & then back the other way to fully hot. If not it is piped-up wrong, we see it all the time, you are not the first.

 

[Mike Jackson]

On some showers it is possible to turn the cartridge around to cope with reversed supplies. This may have been done on the old shower.