Cold water storage temperature

[MOSSEP]

Got a question


A care home I work for has had a Legionella Risk Assessment done, it has highlighted that the water stored in the cold water tanks is over 20 deg C (they recorded it as 20.4 deg C) and its distributed at between 20.8 and 25.6 deg C at various outlets.


I measured the water temp coming into the premises and its 17.3 deg C, so its not a massive variable in temperature between the incoming and the stored. The loft tank is fairly new and is insulated (its a large black PVC tank, not an insulated GRP tank), but the cold water main running through the property doesn’t look to be.


I thought about running a new insulated cold water supply direct to the loft, but the route is horrible, its through 3 floors of a town house with laminated or vinyl flooring everywhere. Anyone got a simpler idea? I could go externally, but I then have the risk of freezing in the winter and exposure to more het from the sun in the summer.


Cheers


Martin

 

[Ch4 plumbing]

Reduce the size of the cwsc? Is the turnover high enough? Is the water just sitting their for too long?

 

[Ch4 plumbing]

Re reading your post the cold down service must be getting heated to have a temp difference of 20.4 at the cwsc and 25.6 at some outlets so maybe lagging pipes is an option?

 

[leethegasman]

Instead of putting in a smaller cwsc install a drop arm float operated valve, to lower the water level-volume a least that way you can increase in future if needed.

 

[Fallon1982]

You sure there isn't a shower valve or mixer tap pushing warm water back up the cold feed into the tank?

I had it with a thermostatic shower before. When I looked into the top of the CWST you could see a warm flow of water coming up the cold feed.

It's a long shot but worth checking.

 

[MOSSEP]

Thanks for the thoughts guys, I think I'll try Lee's suggestion first. Although I like work, I don't like the idea of lifting boards throughout the home to lag stuff so will give it a go first.