Water cistern: precautions against freezing of water

[pambar]

Hi guys,

I need some advice on whether to switch off my hot water storage cylinder while being away for almost a month before and after Xmas.

I have a vented hot water storage cylinder in my bathroom and a water cistern in the loft. If I leave the power on, the hot water storage cylinder will keep heating up the water overnight. But I was planning to save some power and switch it off during my holidays.

Do you think the the water cistern in the loft could freeze if the hot water system is off overnight? I'll be away between the end of December and mid January when the temperatures often drop below zero? Am I crazy to switch off the hot water cylinder?

What do you recommend I should do?

Thanks!!

P

 

[HERTS P&D]

You have two choices:

1. Leave your heating on set at 10 degrees, turn the hot water off.

2. Have a complete drain down.

Andy

 

[pambar]

Hi Andy,

Thanks for your advice. Most helpful. I really wanted to avoid draining the whole water system.

Do you think that having the hot water cyclinder on every night will make a difference or at least lower the risk of burst pipes? I won't be home for 3 weeks, so there will be no water running at all .

Do you think a burst pipe & frozen cistern can happen regardless of whether the cylinder in my bathroom heats up the water overnight?

Thanks again!

P

 

[HERTS P&D]

For piece of mind you should leave your heating turned on and the hot water turned off.

Turn off your incoming water mains, then open the kitchen tap to make sure its off and leave open.

Also make sure your cold water tank in the loft is well insulated.

Andy

 

[pambar]

Oh thanks Andy. I'll definitely check the insulation in my loft.

So having the heating on and keeping the place warm is better than having the hot water cylinder heat up the water overnight?

One more question: if I want to drain the system, shall I just turn off the incoming water mains and turn on the bathroom taps to get rid of the water in the cistern?

When you turn the mains back on will it automatically fill the cistern again?

Thanks

 

[Charnwood]

Also make sure your cold water tank in the loft is well insulated.

And make sure there's no loft insulation between the ceiling and the tank.
This will allow heat from below to help keep the tank from freezing.

 

[pambar]

Hey thanks for your advise. I was now thinking of doing a drain down. I'm only leaving for 3 weeks but it's between Xmas and new year when temperatures can fall below 5C.

I know how to turn off the water supply from the mains but I'm not sure how to drain the cistern in the loft.

Do I simply need to open the taps in the bathroom which are directly served by the cistern?

And when I come back, do I only need to turn the mains on to re-fill the cistern?

Thanks

 

[SimonH2]

I know how to turn off the water supply from the mains but I'm not sure how to drain the cistern in the loft.

Do I simply need to open the taps in the bathroom which are directly served by the cistern?

Yes, just turn on a cold tap that's fed from it - no need to run a hot tap and waste the heat that's in the how water cylinder. When the cold tap stops flowing, you can open the hot tap to drain the pipes as much as you can.
Bear in mind that you won't drain the hot water cylinder from the taps - but that won't freeze if you leave the heating on low.

And when I come back, do I only need to turn the mains on to re-fill the cistern?

Yes, just turn the main stopcock on and it will refill (it's controlled by a ballcock).

Just be aware that a pipe could have frozen and split, so be on the lookout for leaks that wouldn't show with the system drained.

 

[fishhead1]

Could also leave loft hatch open

 

[big-all]

if you do choose to turn the tank on 30 mins a day maximum will stop it freezing
if the header /storage tank are above the immersion then if lagged open the lagging at the top to let heat out to warm the tanks above and leave on for an hour
this will only help if the tanks above are lagged and topped with no insulation underneath