Thermostatic Mixer Taps

follows2006

Good afternoon,

 currently we have a standard bath mixer taps for bath/ shower function so play the roulette trying to get the temperature right. I have been looking at thermostatic showers but am put off by the drilling and pipework needed to install.
 I have seen thermostatic mixer taps like https://www.amazon.co.uk/ENKI-Modern-Thermostatic-Mounted-Bathroom/dp/B00VAPXWQS/ref=sr_1_1_sspa?crid=3MYU5Q8VYGCCT&dchild=1&keywords=thermostatic+bath+mixer+tap+with+shower+attachment&qid=1618835600&sprefix=thermostatic+bath+mixer+tap%2Caps%2C806&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyRU1GQ0lZV1VTV1g5JmVuY3J5cHRlZElkPUEwMzc4NjIxUVYyWldKTDE0SVIwJmVuY3J5cHRlZEFkSWQ9QTA5NTE3NTcyTEdDUDlPNDNJOE41JndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ== ,

would this mean simply a swap over from my current standard mixer but have the same function as a thermostatic shower?

Grenage

Exactly so; I fitted similar in my last bathroom.

neilmcl

Just be aware, that when running a bath you won't be able to run the hot tap at it's highest temp as most thermostatic mixers will have a maximum safe hot water temp of around 46C. So if you like really hot baths during the winter you may struggle to get the temperature you like.

Also, as an aside, you don't have to copy and paste the entire link into your post, all you need is the info up to the question mark, eg, https://www.amazon.co.uk/ENKI-Modern-Thermostatic-Mounted-Bathroom/dp/B00VAPXWQS/ref=sr_1_1_sspa

Moss5

The spec for your Amazon tap is: -
Minimum 0.5 bar water pressure, 1.0 bar recommended for best performance.
To achieve the 1.0 bar pressure on both hot and cold supply to the tap, you would need a combi boiler, or unvented hot water tank.
If you have a cold tank in your roof space, then your hot water is arriving at the tap at a lower pressure than your cold water.
All these modern mixers are designed for high-pressure systems at equal pressure.

grumbler

Moss5 said:

If you have a cold tank in your roof space, then your hot water is arriving at the tap at a lower pressure than your cold water.

How come? With a tank in a loft it's typically the same (low) in a bathroom and higher only in a kitchen where cold water is from mains.

All these modern mixers are designed for high-pressure systems at equal pressure.

Equal - possibly, but not necessarily high. For normal taps you can usually find this information in the specification.

As usual, Amazon is hopeless about specs, but for this tap it's

"Minimum 0.5 bar water pressure, 1.0 bar recommended for best performance."

With a tank in the loft the pressure is usually lower than 0.5bar. In this case it will work, but the flow will be very low.

Moss5

In the same bathroom, the toilet and basin may use mains cold supply. The bath mixer must not be connected to mains cold and low pressure hot.

grumbler

Moss5 said:

The bath mixer must not be connected to mains cold and low pressure hot.

I think, theoretically it can - like many kitchen mixers are - if designed accordingly.

In the same bathroom, the toilet and basin may use mains cold supply.

I've never seen this and this sort of defeats the purpose of having a tank in a loft.

Jeepers_Creepers

grumbler said:

Moss5 said:

The bath mixer must not be connected to mains cold and low pressure hot.

I think, theoretically it can - like many kitchen mixers are - if designed accordingly.

In the same bathroom, the toilet and basin may use mains cold supply.

I've never seen this and this sort of defeats the purpose of having a tank in a loft.

I think Mos's points should be noted by the OP before they fit any thermo mixer.

All the thermo shower mixers I've looked at state to ensure an even pressure balance. There might be some specialised models which can cope, but these are few and far between.

I have also read on fora, forii, forums about some bathrooms having cold mains supply and an unvented stored hot, so completely different pressures. Not common, but does happen (possibly to have drinking water in an en-suite for example? I don't know).

It's just an obvious thing that Follows should look at.

grumbler

AFAIK, unvented means that the hot water is under mains pressure. That said, I am not sure about the regulations for thermostatic valves in this case - I can imagine hot water sucked to the mains from a hot water tank.

Regardless, as a side note for the OP, it's possibly easier to have a (semi-)hidden thermostatic valve (22mm for low pressure) set for higher temperature and connected to the hot water inlet of a usual mixer tap of the bath and, possibly, of the basin as well. You make the water a little colder, if needed, but using the cold water tap of the mixer tap.

E.g.

ic

Toolstation sell bath filler tap legs, that allow you to mount any wall mounted thermostatic mixer to your bath.  As we don't take baths only showers, I've swapped our bath taps for a thermostatic shower mixer.  It's a temporary job ahead of ripping out the bathroom when an extension is done in the near future.

https://www.toolstation.com/search?q=bath filler legs

follows2006

ic said:

Toolstation sell bath filler tap legs, that allow you to mount any wall mounted thermostatic mixer to your bath.  As we don't take baths only showers, I've swapped our bath taps for a thermostatic shower mixer.  It's a temporary job ahead of ripping out the bathroom when an extension is done in the near future.

https://www.toolstation.com/search?q=bath filler legs

Thank you all for the input, @ic didnt know about the tap legs and same dont really use the bath at all so this would be a great solution until we have a full refit next year.