Shower - Hot and cold plumbed wrong way, or not?

[nervous123]

I know I've posted this once before, but wanted to double check before I get someone to smash up my tiles!

Our Crosswater shower thermostatic mixer valve doesnt quite seem to work.

Turned fully to the left gives perfectly hot water, and fully to the right gives perfectly cold water. However, if starting from the right, it only mixes nicely til valve has been turned about a third (=pleasantly hot). Thereafter, it is boiling hot - all the way to the left. {Also, once hot, turning the valve back to the right does not reduce the temperature.}

So....does this sound like the hot and cold supplies are plumbed the wrong way round - or, as I am hoping - that the Crosswater cartridge is dirty or faulty?

Thanks a lot.

 

[Axel]

Crosswater shower valves are a bit dodgy, I have found. Even the replacement cartridges can play up even when new.

I believe that on coldest setting the valve shuts off the hot flow, so if it was piped the wrong way round, then the water would come out ho on the coldest setting.

I have seen new Crosswater valves supplied with the temperature labeling the wrong way round, just to confuse matters further.

If you take out the cartridge, you should be able to see the two ports the hot and cold come through. Turn off the cold and hot supply, and then turn on only one of them gently and see which port the water comes through. Can't tell you which port is which but their tech support should know.

This is a test you can do without taking off tiles.

 

[nervous123]

If you take out the cartridge, you should be able to see the two ports the hot and cold come through. Turn off the cold and hot supply, and then turn on only one of them gently and see which port the water comes through. Can't tell you which port is which but their tech support should know.

This is a test you can do without taking off tiles.

Thanks once again for your helpful advice. As we are still within the warranty (by 2 days!) the retailer I bought the parts from has ordered a repalcement cartridge which has already arrived from Crosswater.

Is the removal and replacement of a cartridge something that anyone can do, or should I get a plumber in? Don't want water gushing all over the place...!

 

[keego]

Looking at it from the front, hot should be on the left & cold on the right.

 

[nervous123]

Looking at it from the front, hot should be on the left & cold on the right.

So seems it has indeed been plumbed 'incorrectly'. (In fact, the valve in the bath is the same.)

However - surely that would merely mean that we need to turn our valves in the opposite direction to most other people - not that the water doesnt mix correctly?

 

[keego]

Thermostatic valves are designed to have hot & cold coming in from one way only, plumbing it in back to front will confuse the hell out of the valve.
A repipe is the only answer I'm afraid.

 

[Axel]

A runaway positive feedback loop...

 

[muggles]

Unfortunately it's not that simple, the way most thermostatic valves work means that they must be plumbed in the correct manner or you'll experience exactly the problems you have described. A few permit this issue to be resolved by simply removing the cartridge, turning it through 180º and refitting, however I can't say whether this is the case with yours or not. If it is then great, if it isn't you need to get it repiped

 

[alan999]

Hi
If a repipe is necessary remember there may be a place you can access the pipes and switch them over without smashing the tiles up.

 

[nervous123]

Sorry everyone - I must have got confused cos I've checked again and full turn to the left is hot and full to the right is cold. So it seems to have been plumbed correctly after all! [Apologies if I've wasted anyone's time]