Thermostatic shower, toilet flush gets hot?

[Robhingston]

I have a new thermostatic bath tap shower mixer which works fine, however when someone flushes the toilet or uses the cold tap it goes very hot . Thats not supposed to happen on the thermostatic mixer taps. I thought thermostatic shower mixer taps would eliminate that problem,

 

[OwainDIYer]

Combi boiler? The cold feed to the combi boiler may be affected by the toilet.

Also not all t'static mixers play nicely with all models of combi boilers.

Could the t'static mixer be plumbed in hot-to-cold and v.v?

 

[Robhingston]

Thank you for your professionalism.. Yes it's connected correctly, I have an immersion heater plus my hot water is connected to a pump due to vary little pressure so hot water is slightly stronger pressure then the cold water from the mains, I just tested it out again. This time With a temperature probe I find getting 34c from the t'static mixer but as soon as I put on cold water kitchen tap I could see the temperature rise to 52c and stay at 52c for as long as I run the cold water k tap..

 

[OwainDIYer]

Possibly the water pressure is over-riding the cartridge.

The pump hot water pressure may be higher than the shower is intended for; try turning the pump down if possible.

Check flow regulators at mixer outlet and handset outlet, clean if necessary.

 

[denso13]

They can be temperamental if the pressures aren't equal. Which tap is it?

 

[Robhingston]

I turned the hot water pressure down so its the same pressure as the cold now but if I flush the toilet or turn on the sink cold tap etc you can feel the shower getting really hot , maybe its the thermostatic shower mixer not working ? any advice would be valued

 

[flameport]

If you have a mixer with one side connected to cold mains and the other a pumped supply from a cylinder, it will never work properly.

Either have both hot and cold pumped from a storage cylinder & tank, or have both via the mains.

 

[buck51]

I got the wrong end of the stick.

 

[buck51]

Miss read your post.

 

[denso13]

If you have a mixer with one side connected to cold mains and the other a pumped supply from a cylinder, it will never work properly.

+1

 

[leakydave]

You really need balanced supplies to the shower. A pressure reducing valve MIGHT correct your problem but ideally you should be pumping both hot and cold water to the shower.

 

[Robhingston]

thanks, I was told the wrong thing at my local pumping shop I was told that a thermostatic bath tap shower will balance out the pressure and temperature no matter what my set up...

 

[OwainDIYer]

thanks, I was told the wrong thing at my local pumping shop