While on holiday turn off water with open vented system?

[Marcus67]

It might seem an odd question in this weather, but the summer holiday has got me thinking about the winter holiday

After reading the relevant posts on this forum, I gather that when going on holiday during the winter the best thing to do is to leave the heating on (with the thermostat at a lowish temperature) and to turn the water off at the mains.

However, my heating system is an open vented system. As I understand it, such a system loses water from evaporation and it is then topped up by being connected to the mains water. Clearly this topping up will no longer happen if the mains water is turned off. Presumably the tanks in the loft (the cold tank and the F&E tank) will have a sufficient supply of water for the system to run without problems for some time without topping up from the mains. But I'll be away for more than a month (yes, lucky me ). Will the system run out of water over such an amount of time?

 

[xr4x4]

if it does, you have a problem..!

try turning it off now (or tie up the ball cock) and keep an eye on it over time, see if it drops.

 

[Armo74]

It would not be a good idea to turn the mains supply off and leave the heating on. I do not see the point in turning the mains off if you are going to leave the heating on a low temperature anyway. What some people do if they are going away for a long period of time is drain the heating system and the hot and cold supply.

 

[xr4x4]

this always gets me thinking....

why cant you use antifreeze in the heating system?

 

[Armo74]

What would concern me would be if you were to get a slight leak.

 

[xr4x4]

What would concern me would be if you were to get a slight leak.

why, it would only have to be a very low concentrate.

 

[Marcus67]

It would not be a good idea to turn the mains supply off and leave the heating on. I do not see the point in turning the mains off if you are going to leave the heating on a low temperature anyway. What some people do if they are going away for a long period of time is drain the heating system and the hot and cold supply.

Keeping the heating on will prevent pipes from freezing, but there are other reasons why a water system can start leaking. A leak while the mains is on for days can have pretty devastating effects. So if possible, I would like to turn the water off.

I've considered draining the whole system and I might still do that, but judging from replies to similar questions on this forum it seems that the most common advise is to keep the heating on rather than to drain the system.

 

[Marcus67]

if it does, you have a problem..!

Are you saying that my assumption "As I understand it, such a system loses water from evaporation and it is then topped up by being connected to the mains water" is wrong (at least if the system is operating as it is supposed to). That would be good, since then I don't have a problem at all and I can just turn the mains water off.

 

[xr4x4]

if it does, you have a problem..!

Are you saying that my assumption "As I understand it, such a system loses water from evaporation and it is then topped up by being connected to the mains water" is wrong (at least if the system is operating as it is supposed to). That would be good, since then I don't have a problem at all and I can just turn the mains water off.

Yes it will lose a tiny amount over a long period of time.

My point was that if it lost a large amount of water over a small amount of time, you have a problem.

 

[Whitespirit66]

this always gets me thinking....

why cant you use antifreeze in the heating system?

You can, just that it's very steep. 40 quid for 5 litres, but you need 4 of these for a 10 rad system.

http://www.screwfix.com/p/sentinel-...g-_-Sentinel X500 Inhibited Anti-Freeze 5Ltr#

If you can do it yourself, much cheaper to drain down.

 

[Marcus67]

Yes it will lose a tiny amount over a long period of time.

My point was that if it lost a large amount of water over a small amount of time, you have a problem.

My question was about the long period of time: is the loss still a tiny amount when accumulated over a long period of time or do tiny amounts of loss every day add up to something substantial and potentially problematic over a long period of time such as a bit more than a month?

 

[JohnD]

over a month the loss should be imperceptible.

I expect you have a close-fitting lid over the F&E, same as you have over the cold water tank, to keep drowned wildlife out, and this will reduce evaporation.

the results of a burst pipe while the house is unoccupied can be catastrophic, so I would say, leave the heating on low (your insurers probably say 12C) and turn the water off.

It is an advantage to drain the cold tank as this is a large amount of water thay can come through the ceiling if there is a burst.

Obviously lag all pipes in unheated areas, but this will delay freezing, not prevent it.

this was a ceiling View media item 30562

 

[Dan Robinson]

Don't forget to augment the lagging with ptfe - it'll work wonders

Seriously, though, John and the others are right. Turn off and run the cold tap dry.

The consequences of a burst pipe at the start of your holiday don't bare thinking about.

Friends of ours (Sicilian husband, and Japanese wife) didn't ask/listen to advise, and their house was uninhabitable for 4 months - they were living in a hotel with. Toddler afflicted with cancer whilst the insurance zombie fitters made a pigs ear of their house.

 

[Marcus67]

Many thanks to those who replied. I'll turn the water off and keep the heating on at a low temperature.

 

[SimonH2]

Also check what your insurance policy says about it - they vary quite a bit.

Some will be OK with the heating on. Some will withdraw cover if you don't shut off and drain down. The period you can have the house empty before these requirements kick in varies.