Water milky colour & too hot

SMG · 28-03-2007, 17:10

My Dads residence has had a new hot water system fitted. The water is too hot & will burn your hands, & is a milky colour, which doesn't fade, even if you run the tap for long periods of time. It never used to be before this work was done. The cold water is clear. I have complained but the answer I have been given is:

The hot water comes from a different feed than the cold.
The system is pressurised.
The thermostat is set at 50 degrees & cannot be set lower.

Personally, I think these answers are rubbish, & they are just fobbing us off. Can anyone help!

**Rob** · 28-03-2007, 17:16

When you say residence, I'm assuming this is a building with a communal heating system.

Not sure about the colouring but temperature wise you need to heat hot water to 50-60 deg C to kill off bacteria such as legionella. That's critical in places where people may be vulnerable to infections. It's why in hotels and places you often see notices of "very hot water", etc.

For most people that is too hot for comfort. If occupants might be vulnerable such as the elderly or in nursing homes I would expect there to be some sort of mixer system at the taps / baths / showers to restore temperatures to something tolerable.

punky · 28-03-2007, 17:19

White colourisation is normally limescale build up in the pipes.

Wicked_and_Crazy · 28-03-2007, 17:36

Wrong Forum?

**Rob** · 28-03-2007, 17:36

Quote:

Originally Posted by Wicked_and_Crazy

Wrong Forum?

Well spotted that man, moved

Taf · 28-03-2007, 17:39

White colour? Draw a glassful and in a minute it should go clear... it's tiny air or chlorine bubbles probably. Does it smell a little like bleach?

50C water temp is not required if you don't have a cold water header tank (where legionella will get in and breed). 40c will reduce the risk of scalding for older or younger people in the house.

Wicked_and_Crazy · 28-03-2007, 17:43

Quote:

Originally Posted by Taf

50C water temp is not required if you don't have a cold water header tank (where legionella will get in and breed). 40c will reduce the risk of scalding for older or younger people in the house.

I thought legionella lived in warm water not cold (ie in cooling towers)? Most houses have cold water header tanks but you dont have your water temp set that hot

I thoguth the high temperature was a H&S thing for water in public places?

murfitUK · 28-03-2007, 18:03

The milky colour could be caused by the water being saturated with millions of tiny little bubbles. Run a sinkful of hot water and let it sit for 5 minutes. If it clears, its bubbles.

Its like if you boil an egg - you can see the little bubbles forming all around the pan as it heats up.

**Rob** · 28-03-2007, 18:44

Quote:

Originally Posted by Wicked_and_Crazy

I thought legionella lived in warm water not cold (ie in cooling towers)? Most houses have cold water header tanks but you dont have your water temp set that hot

I thoguth the high temperature was a H&S thing for water in public places?

Legionella loves water at about 20deg C. That's why air conditioning cooling toweres are so vulnerable. But it's also been found in things like showers where the water cools down sits around for a while etc. The problem in fact is worst with things like showers as you are likely to ingest the small water droplets.

Many domestic cold water tanks are inadequately insulated, don't have proper lids and stuff. They become a haven for bacteria. Thus water should be properly heated, and it's not a good idea to drink from downservice taps (even washing teeth is a risk

)

Public buildings, offices and anywhere with larger communal tanks such as blocks of flats should have a maintenance programme in place to regularly sterilise the pipe systems. Even so proper heating of hot water will be needed in conjunction with maintenance.

28-03-2007, 19:18

If i remember rightly the water temp has to be 65degrees to meet Health and Safety regulations for public places. The milky water is due to calcium carbonate (Limescale) as Gavin said. I think high temperatures bring it out of the water, thats why limescale builds up in kettles, washing machines and dishwashers.

altis · 28-03-2007, 19:33

Indeed, the hot water system must, by law, to be set above a minimum temperature to ensure that legionella cannot grow.

However, there is another law that prevents the water for people 'at risk' (like the elderly) being above 38 degrees. The problem is easily solved with a thermostatic mixer valve.

Some info here:
http://www.rwc.co.uk/content.aspx?page=ABOUTTMV

If the 'residence' is intended for the elderly then, by law, it should have these mixer valves installed.

Also see this:
http://news.bbc.co.uk/1/hi/uk/3371197.stm
Warning: a bit gruesome!

greencreeper · 28-03-2007, 22:30

The milky colour is probably just air in the system. It's harmless. My hot water is the same. As for the temperature - I've noticed that it seems to vary depending on the flow of water, whether the central heating is on, and whether hot water has recently being delivered. I've burnt myself a few times. Would be nice if someone could develop a hot water system that delivered hot water at a set temperature. That said, it might be worth someone looking at the boiler to see if it is working correctly.

Mr_love_monkey · 28-03-2007, 22:42

I was suggest going to see a doctor, but then I realised you were talking about taps

altis · 28-03-2007, 23:14

Everything you wanted to know about TMVs:

http://www.buildcert.com/PDFs/TMV2/IP14_03.pdf

SMG · 29-03-2007, 00:01

Thanks very much. The water does clear after a minute or so, so I`m happy there is no contamination. I have enough information to present to the managers of the residence, a comprehensive array of recommendations & health & safety rules regarding scalding. Some of the people there are incapable of seeing any dangers, "Learning Disabled". Thankfully, my Dad & some others are just elderly, & still have their faculties. But I do fear someone will burn them selfs sooner or later.