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I am looking for advise on how to stop the cold tank water getting so cold. Because the tank is in the loft its drops to around 1/2 Centrigrade (during the UK winter time) and when mixes with the hot water for a shower makes the water just luke warm. How can I increase the temperature so the cold water is not so cold?
The hot water is as hot as it can get at the moment (top end of the thermostat) and is nice and hot when it just run through a single hot tap, advise please?
 
Remove any insulation from underneath it. Lag the sides and top of it really well. This should keep it at approximately the temperature of the room below.
Or have you already done this?
 
There's your problem. It should be, by the way. Also, the dip tube is helpful in keeping out cold draughts from the overflow running into the cistern.

If you're using the water in your shower etc, you may want to make sure it complies with the rest of the Water Regulations (which have superceded the old Byelaw 30, but here's a link to a rough guide to what a cistern should have:

Byelaw 30 and Byelaw 60 kits - DIY Plumbing
 
Good question. We've worked out why the cistern is so cold, but not why the shower is so cold!
 
I am looking for advise on how to stop the cold tank water getting so cold. Because the tank is in the loft its drops to around 1/2 Centrigrade (during the UK winter time) and when mixes with the hot water for a shower makes the water just luke warm. How can I increase the temperature so the cold water is not so cold?
The hot water is as hot as it can get at the moment (top end of the thermostat) and is nice and hot when it just run through a single hot tap, advise please?

Hello Neil Graham,

The Mains Water which is filling your CWS Tank could easily be as cold as only 2 or 3 degrees during the cold Winter periods.

Try checking the Mains water temperature with a thermometer at your Kitchen Mains tap.

I would be fairly sure from investigating similar issues in the past that the Air temperature of the Roof space is not causing a significant `Fall` in the water temperature - but with a completely uninsulated Tank it may be lowering the temperature by a degree or two.

As the incoming Mains water will be so cold - 2 or 3 degrees - unless the CWS Tank is experiencing some `wind chill` from Roof vents - the temperature in the Roof space may not be any colder than that - so may not be lowering the water temperature ?

As Member Ric2013 correctly advises - You definitely should Insulate the CWS Tank - removing any Loft Insulation from directly below the Tank - and fit a Bylaw 30 Kit including a tight fitting lid.

That will offer protection from Freezing - and just as important - protection against `Heat Gain` in Summer as You definitely do not want the stored water warming up to above 20 degrees [Legionella risk].

As You know Roof spaces can get VERY Hot during very warm Summer days - sometimes heating up to over 40 degrees - and also the Mains Water can often be about 15 degrees as it enters the CWS Tank - so the water in an uninsulated Tank can increase to above the 20 degree limit on very Hot days depending upon the amount of draw off / refilling.

However I know from experience that insulating the Tank / removing insulation below it will NOT significantly `Raise` the temperature of the CWS Tank water in Winter.

The stored water will definitely NOT `warm up` to anything like the temperature of the Room below - even a temperature of a couple of degrees would be optimistic - and with regular draw off / refilling of the Tank probably impossible.

I have actually demonstrated exactly this to the Customer on a couple of Jobs where they thought the water temperature would increase:

Both were on properties which were not being lived in for the 3 or 4 days of the `Tests`.

The CWS Tanks were really well insulated - no insulation directly below the Tank base - Heating set to operate Morning 5 hours - and Evening 7 hours - and ZERO Water draw off / refilling for 3 or 4 days.

On each occasion when I then tested the temperature of the water in the CWS Tanks it had not increased more than 2 degrees above the temperature of the incoming Mains water - I was using a really accurate Kane May Digital Thermometer.

Sorry to be the bearer of `Bad News` - but the good advice to Insulate the CWS Tank / Bylaw 30 Kit etc. is still an `upgrade` to your Plumbing / CWS Tank.

Regards,

Chris
 
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My money's on the shower mixer, especially as the water is hot enough from other taps. If the water's not very hot in the hottest setting, the thermostatic cartridge could be faulty inside mixer. First check to see if there are any filter screens on the inlets and check that they're not blocked.
 
Proper and sensible way to keep a cold water tank in a loft warmer and safer from freezing, (besides the usual keeping loft insulation away from base and having a tank jacket) is to make a framework around the tank area. This will effectively keep the tank separate from the cold loft in its own space, being heated a little from heat below through ceiling to a reasonable temperature.
The framework only needs even to be light frame with polythene sheet to provide an enclosure.
 
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