Crosswater shower valve only producing tepid water

10 Oct 2008
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United Kingdom
I've lurked for a few months and now I've a question.

I have a Crosswater thermostatic mixer valve with two independent outlets. I have a pumped water supply that produces excellent pressure to hot/cold taps in the same room as the shower.

Recently (in the colder weather), the shower has only produced (at best) tepid water. If I leave the cold tap running and turn the valve up to max temperature, the temperature of the shower is able to reach a nice hot flow. If I stop the cold tap, the flow then returns to (at best) tepid. It's not going to be enough for winter.

I've taken the decorative parts of the mixer apart (ie, the front bit of the temperature dial, to expose the brassy bit of the valve) and turned the valve to its absolute maximum. I'm now stuck for what to look at next. Is there any possibility that the valve is simply not reducing the flow of the cold water enough? Is there something mechanical a bit further back that would only be revealed if I took off the whole face plate (which feels like it's been sealed in place by the fitter)?

I know Crosswater has a 15 year warranty - thing is, the fitter who did the bathroom didn't finish the job properly (problem with a cupboard/worksurface) 12 months ago. What can I do first off in this instance?

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The hot pipe to the mixer is hot. As hot as the water coming out of the taps in the bathroom.
sounds like you have a faulty or seizing thermostatic cartridge.
which needs the mixer stripped down to gain access
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Grrr. That's what I thought/feared.

Couldn't find anything about Crosswater cartridges on the internet anywhere. Are they a standard part that can be serviced by a reasonbly competent DIYer? (That's assuming I can get the faceplate off) Or are they something I could get lined up in advance of a qualified plumber turning up?
Thanks seco for all your replies.

Now, where can I find out what I need to buy? Or where to buy it.
I do not think it is the valve else the valve would not get hot when a cold tap was turned on.

Crosswater have only used two thermostats in there valve the latest one that has been around for 18 mounths and the old IB one that they use prior to that one.

I suspect that you are using a salamander pump?
I know mate but it does not mean there is even pressure on both sides.

Salamanders are notorious for air in impellors and loosing pressure on the hot side of the pump.
I've got a Monsoon pump.

What I've done, is to turn up the central heating boiler temperature - this produces hotter water and now I've managed to get hot water out of the shower.

What I'm not sure about is whether or not it will be a problem when I switch my controls from HW Only to CH+HW... let's hope it's not too chilly too soon.

Many thanks for your help. If you did want to suggest a cartridge for me, my controls are shown on the link below

Model 3001RCabout half way down.
Salamanders are notorious for air in impellors and loosing pressure on the hot side of the pump.
What an amazing claim!

Where does this notoriety come from?

How does the air get into the "impellers"?

Why is the pressure loost only on the hot side?
as said the whole supply is pump fed so why isn't the hot taps affected only the shower.
Hi annaX,

I have the same problem with my thermostatic crosswater valve, and wondered whether you managed to solve your problem, aside from turning up the temperature of the hot water?

Would be grateful if you could share your experience.

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