Cascade bath mixer taps

[Lazwal]

Hi, I am after some advice regarding my new bath mixer taps. I have just renovated my bathroom and put a new bath in and changed the taps. We now have what I believe are called cascade mixer taps. Previously we had mixer taps and the shower was run off the taps the shower was acceptable but with these new taps the hot water pressure was low it was a dribble, so I have fitted a shower pump to the hot supply. This has improved the hot water supply but another problem has now shown up. When we try to use the shower you cannot control the temperature. It is either to hot and no amount of turning the cold up alters it. If you start with the cold water and turn up the hot it remains cold. So to sum up what ever you start with either hot or cold you cannot balance it.
If you run the bath you can control the temperature it is only when you turn the mixer valve to use the shower that you cannot control it. I think it may be the mixer valve that is causing the problem so I am after some advice please.

 

[oldbuffer]

Sounds like an unbalanced supply issue, possibly mains cold and tank fed (via pump) hot.

Need to know what sort of hot water system you have:

1. Cold water storage cistern (CWSC) (loft?) and vented hot water cylinder (airing cupboard?).
2. Combi boiler.
3. Unvented hot water system (no CWSC, unvented hot water cylinder.
4. What sort of pump you have fitted, and its output pressure in bar.

 

[Lazwal]

I realised after I posted that I had not given details of my system, It is a gravity fed indirect open vented system. I sat down and gave it some thought and I think you are right. I have gone from one extreme weak hot to powerful hot and unbalanced it. I was thinking(dangerous for me) what if I put a PRV under the bath to reduce the flow to the hot and try and balance it?

 

[Lazwal]

I realised after I posted that I had not given details of my system, It is a gravity fed indirect open vented system. I sat down and gave it some thought and I think you are right. I have gone from one extreme weak hot to powerful hot and unbalanced it. I was thinking(dangerous for me) what if I put a PRV under the bath to reduce the flow to the hot and try and balance it?

Forgot to say thanks for the reply it was appreciated.

 

[Lazwal]

The cold water is fed from the feeder tank in the loft where the cylinder and the new Salamander CT 20 force pump 2 bar is situated.

 

[Hot&Cold]

Hi, I am after some advice regarding my new bath mixer taps.

Sometimes glossy internet adverts dont go into technical detail and expect their products to be professionally installed. its a bath mixer tap and not officially a stand under shower,it can only be classed as a stand under shower if the water provided is suitable in temperature and flow (prevention of scalding) part g.

A deck mounted thermostatic bath shower mixer,with correct commissioning would be suitable,