Thermostatic basin mixer taps

[cbk]

Hi, I'm planning to install an ASHP and local BCO has advised that since this will require the hot water to be heated to 70^o  for Legionell protection, then all taps need to be thermostatic to avoid risk of scalding.  Thermo taps are at least 5 times more expensive than regular mixers so this is a big cost.  Has anybody had the same experience?  Is it really a requirement or just a 'nice to have' ?

 

[dpmiller]

Anti-scalding protection can be a single thermostatic mixer at your hot tank (most come with it as standard now) but many here will counter that Legionella controls are unnecessary in a sealed system full of hygenic water...

[Gone West]

On 16/06/2021 at 07:21, cbk said:

Hi, I'm planning to install an ASHP and local BCO has advised that since this will require the hot water to be heated to 70^o  for Legionell protection

The water only needs to be heated to 65C/70C once a week for protection. I used an EASHP in my last house and heated the water to 45C and lived there for three years without problems. I had a thermostatic mixer on my bath supply as per the regulations. As has already been said Legionella controls in houses are IMHO unnecessary.

[Nickfromwales]

On 16/06/2021 at 07:21, cbk said:

Hi, I'm planning to install an ASHP and local BCO has advised that since this will require the hot water to be heated to 70^o  for Legionell protection, then all taps need to be thermostatic to avoid risk of scalding.  Thermo taps are at least 5 times more expensive than regular mixers so this is a big cost.  Has anybody had the same experience?  Is it really a requirement or just a 'nice to have' ?

 

Your BCO joins the others which talk from yesteryear in a lot of instances. 
G3 requirement kicks in with all UVC installs, and every single UVC I’ve ever fitted ( over the last 20 years ) came with a supplied thermostatic mixer valve aka TMV. 

You set that to 50oC and job done. If it’s a new plumb install then add a second TMV in parallel and set to 46oC and run that to the bath hot supply, or just fit a thermostatic bath mixer tap which is easier. Also nice to have a thermostatic bath mixer tap if hair-wash on a handset is required at the bath.

 

What is the proposed method of carrying out the pasteurisation cycle? ASHP to power up an immersion? 

[cbk]

3 hours ago, Nickfromwales said:

Your BCO joins the others which talk from yesteryear in a lot of instances. 
G3 requirement kicks in with all UVC installs, and every single UVC I’ve ever fitted ( over the last 20 years ) came with a supplied thermostatic mixer valve aka TMV. 

You set that to 50oC and job done. If it’s a new plumb install then add a second TMV in parallel and set to 46oC and run that to the bath hot supply, or just fit a thermostatic bath mixer tap which is easier. Also nice to have a thermostatic bath mixer tap if hair-wash on a handset is required at the bath.

 

What is the proposed method of carrying out the pasteurisation cycle? ASHP to power up an immersion? 

Ah that is good to know. I plan to use an UVC but  didn't realise they have a TMV fitted.  That should keep BCO happy he was suggesting every basin, bath or kithen tap had to be thermostatic type.

EV panels will power immersion for legionella cycle assuming the sun shines otherwise E7

Edited June 17, 2021 by cbk
forgot to answer the question

[PeterW]

@cbk they may not be directly fitted to the UVC but easily installed as it just needs a feed from the hot and the balanced cold from the control set. 
 

If you use a manifold arrangement for the hot water supply then you mix in one place and then feed off to the individual supply points / rooms from there. 

[Nickfromwales]

2 hours ago, PeterW said:

they may not be directly fitted to the UVC but easily installed as it just needs a feed from the hot and the balanced cold from the control set. 

..as in factory fitted. They are directly connected to the UVC by the plumber as the first thing off the UVC, if you're not going manifold / twin TMV ( one for the house and one for just the bath(s)) setup etc. You can mount them anywhere, but for max efficiency you keep them as close to the hot water outlet as possible to reduce losses.