Thermostatic Valve and Tanks

[LappyGB]

Hi there,

Just a quick one, if you have a tank installed for your hot water do they usually fit the thermostatic valve at the tank? Just sorting out the bathroom and noticed there's no valve fitted at the pipework to the bath (unlike my old house where the hot water came straight off the combi boiler and there was a thermostatic valve fitted to the bath's hot water feed).

I've tested the max water temperature at every tap and it doesn't seem to go above 41C so can only assume it's getting regulated at the source but if that's not normal practice would consider switching out the bath taps for a mixer with thermostatic control built in (got a child on the way).

Cheers

 

[CountryFan]

If the property was a new build from 2010 then it should have a thermostatic mixer fitted under or at the bath to prevent scalding. They're not usually fitted as a whole site protection, but could have been done this way. It could be that the temperature is low on the cylinder - it should be stored at 60-65 degrees to kill any harmful bacteria (legionella)

 

[Rodders53]

it should be stored at 60-65 degrees to kill any harmful bacteria (legionella)

Some say not essential on domestic UK chlorinated water and unvented HW cylinders.

Modern heat pump installations make do with an (optional) weekly legionella cycle where the HW is heated to 60-ish. Otherwise HW is stored at lower temps that the HP can manage with good efficiency.

We'd need pictures of the HW cylinder controls and bath (mixer?) taps to determine if any TMVs are fitted.

 

[LappyGB]

Cheers for the replies, house is 7 years old so definitely falls into the new build category (old house was 3 years old, bought from new).

I'll try get up and have a look at the tank, hopefully it's not set to a low temp or there's issues with it, already been through boiler pain after moving in.

 

[LappyGB]

Here we go. Possibly a thermostatic valve in the first pic below the expansion vessel?

 

[CountryFan]

Here we go. Possibly a thermostatic valve in the first pic below the expansion vessel?

View attachment 379234

Think that's a combi valve, which incorporates a safety relief valve, but not a tmv.

 

[LappyGB]

So, if the whole boiler output is low temp how do I adjust that?

 

[CountryFan]

So, if the whole boiler output is low temp how do I adjust that?

On the boiler, there’ll be either a digital display or just a control knob. Also, check at the cylinder.

 

[LappyGB]

Well yeah, the combi is set to 65 for both circuits, I'm thinking more about the tank.

 

[Rodders53]

On the boiler, there’ll be either a digital display or just a control knob. Also, check at the cylinder.

Most likely behind the black plastic panel on the Sapphire Unvented Cylinder.

OP: ensure both Heating mains and the backup Immersion mains are isolated while you look first...
Then assess whether it'll be safe for you to adjust the temp setting while powered up.

https://www.plumbworld.co.uk/docume...heaters-installation-servicing-user-guide.pdf may be the correct manual for it... or not. If you have the original paper version consult that instead.

Consider if it'll be safer to keep the water at the lower temperature and use the immersion once a week to go hotter as a "Legionella disinfect" cycle... At least until you sort out TMV for the bath, showers and maybe hand basins.

Combi may only feed some Hot taps? Or the HW outlet not be used? Some installers use combis as system boilers 'cos they are cheaper (although more complicated) due to volume of sales?

You need to do more investigation of what feeds where for the HW, methinks.

 

[LappyGB]

Thanks for the in-depth reply, pretty sure the tank supplies everything, combi has two outputs, cylinder and rads.

I'm just taking the simple option in the end and will be fitting a new thermostatic mixer on the bath, should be fun with the 2 inches of space to work in!