Thermostatic Mixing Valve

[mick100]

I recently got a thermostatic mixing valve installed. This was put on the flow from from the hot water cylinder so it mixes the hot and cold water for all the hot taps and showers in the house. I have pressurised system. The hot and cold water is pressurised using one pump which is grundfos booster pump.Both hold and cold water are fed to the valve in 3/4" copper pipe and both sources are pressurised from the same pump. I am not entirely happy with the mixer valve, while it prevents very hot water at the taps(which was the reason I got one installed) when the pump is running you will get a flucuaction of temperature at the taps and may get very hot water for a few seconds when the tap is on. What can be done to get better results from mixer valve? Should the plumber have installed any pressure reducing valves and if so do these improve the results?

 

[oz-plumber]

There's no point in putting pressure reducing valves on a pumped supply. You will only cause the pump to stop and start.

Mixing valves do have a thermostat installed and they do take some time to adjust to the temperature set. When the hot water is entering the valve too hot it will over compensate and allow more cold water through.
Once the valve has settled it should provide reasonably constant water temperature.
So it is just something you will have to get used to

 

[Best]

Like any thermostatic mixing valve, turn an outlet on and allow to run for a few seconds before you put your skin near the water.
Note that filters are fitted in supplies to some taps, most shower valves, any pumps and any mixing valves, so need occasionally checked for debris, especially hot supplies. A blocked filter can have same effect of creating good flow when a tap opened for couple seconds and then less flow

 

[AWheating]

What type of mixing valve is it? Most tmv valves should be within 1m of the tap/fixture. A blending valve at the cylinder set a 60 is fine.

 

[mick100]

There's no point in putting pressure reducing valves on a pumped supply. You will only cause the pump to stop and start.

Mixing valves do have a thermostat installed and they do take some time to adjust to the temperature set. When the hot water is entering the valve too hot it will over compensate and allow more cold water through.
Once the valve has settled it should provide reasonably constant water temperature.
So it is just something you will have to get used to

Thanks for advice. It has been in use for a while and the issue is the intermittent burst of hot water I get when the tap is open. This will continue for as long as the taps are running and occurs at all hot water outlets. Would pressure differential have an impact on the way it mixes as I imagine the pressure from the hot supply is a lot higher than cold supply and if both sources are pumped by same pump then its imbalanced?

What type of mixing valve is it? Most tmv valves should be within 1m of the tap/fixture. A blending valve at the cylinder set a 60 is fine.

Its an ESBE VTA322

 

[Welder]

Personally, I've found you have to be very careful about choosing TMVs. They are NOT all equal.

I would talk to the manufacturer to see if it will ever perform properly in your circumstance rather than have us provide guesses - albeit educated guesses