What shower for combi (thermostatic vs pressure regulating)

[LankyPaddy]

Thinking of getting a Vaillant Ecotec plus 837 installed. I've been told a pressure regulating shower is the best to have (Mira Combiforce/Combiflow).

I'm unsure why these would be better than a thermostatic.

What difference would I see "in the real world"?

 

[ianniann]

Looks like you're sliding off the front page without a reply ...

Not sure how you define "best", but there are certainly differences.

Pressure regulating showers maintain equal quantities of hot and cold water through the head. You can adjust the relative quantities to get the temperature you want. If something happens to change the flow rate of either the hot or cold water (thanks for turning on the cold tap, kids!) this type of shower will adjust and maintain a constant temperature. However, if the temperature of one of the inputs (usually the hot, obviously) changes then it will carry on blindly delivering the same mix and give you a big shock.

Thermostatic showers are more complex and often more expensive. They measure the temperature of the water and adjust the incoming flow to maintain it at the level you have set. They can compensate for both pressure and temperature changes. This also makes it easier to separately control the temperature and flow rate. Thermostatic showers are sometimes "digital" with quite sophisticated controls. such actual temperature setting and memory.

So you might say thermostatic shower valves are "better", but a pressure balancing valve will work perfectly well in most situations. It will struggle when the hot water temperature varies, perhaps due to other people drawing hot water from a comb, and you probably won't find the more complex control on a simple balanced valve.

 

[LankyPaddy]

Thanks for the reply, the recommendation came from a plumber who said the Mira Combiflow/force showers are "better" than thermostatic ones when you've a fully modulating combi.

I didn't know if a thermostatic shower + combi caused some sort of issues which a pressure regulating one overcame?

I'll e-mail Mira and see what they say the advantages would be with one over the other.

Thanks again.

 

[LankyPaddy]

Emailed Mira asking what the difference would be in the real world, got back a standard reply about how pressure/thermostatic showers work and allow for a comfortable showering experience +/- 1*c.

The Combiforce/Combiflow cost £250-£300, which is the same as the Excel thermostatic.

I'm going to assume there would be no difference and go for the one my wife likes best - probably the Pace Ev for £160