Thermostatic shower/tap mixer.

[Steve]

I'm having great problems with a thermostatic tap/shower mix I've fitted to the bath. I can only get, at best, luke warm water out of it,

even when it is set on it's hottest setting. The cold water is fed directly off the mains, with plenty of pressure, the hot is fed from my

combi-boiler, at about 70C, which is a lot lower pressure. If I put a kink in the cold water pipe to the cold side of the tap it works fine.

Could somebody please tell me if I'm doing something wrong or whether this is a common problem. Can I buy something to restrict the flow of

cold water to the tap? But would this make the shower part of the tap useless, due to lack of pressure?

Any help/advice would be greatly appreciated.

Thank you in advance.

[John Stumbles]

If it's a combi the pressure should be the same. The flow will be less, of course. If you're getting hot water at 70C from the combi there's something very seriously wrong with it: 50C is pretty much scalding.

One thing to check is the temperature of the hot water as it enters the valve (feel the pipe with your hand). Is it hot or lukewarm?

Sounds as if the mixer is duff: it should restrict flow of cold water to achieve the desired temperature at the outlet. If you're having to restrict the cold flow yourself then the mixer's not doing its job.

[Christian McArdle]

You need to work out why. Is it fed from a tank for some reason? Is there a pressure reducing valve on it? The pressure should normally be almost identical to the cold mains otherwise.

Well, if experiment shows that restricting the cold works, then you can restrict it. I would use a normal isolation valve (you may already have one in line) and just turn it down until it works.

If it works fine with a manually applied kink, then it will work fine with one applied by a valve.

However, ensure that the problem isn't that the flexible hose to the hot has twisted. This can happen and could be the reason for your perceived low pressure on the hot side. A twist in the hose isn't as obvious as a kink, but can be as restrictive.

Christian.

[Maurice Hood]

The problem could be the INNER of the flexy hose. Take it off both ends and lay it straight and smooth it out to reset the inner