freezing pipes

[SS]

Hi guys looking for an answer re frozen pipes.

dad in laws house lying vacant at the moment (hospitalised) and just realised after my wife had been down, she turned the elec off, meaning the central heating will not have been working over the last week of the cold spell (minus 6) So good likely hood of frozen pipes. Hopefully not burst but possibility.

My intention is to turn the water off at the mains, as I am to far distant to go back and forth to keep an eye on it. Is it best (assuming nothing burst) to turn off at the main and leave the taps open to ease expansion?

Any ideas.

[Phil L]

Yes, and flush the toilet too, and run the hot water off for a while, which may empty any header tanks and therefore drain the pipes leading to them. Don't forget outside taps - the idea is to get rid of as much water in the pipes as possible, where there's a chance it could freeze, expand and damage the pipe walls.

[Harry Bloomfield]

SS formulated the question :

I would suggest turn the water off at the stop tap and open the taps to let it all drain down. There might also be a possibility of the heating system having frozen. If you are sure that has thawed out without any leaks, it might be worth just leaving that on at a very low setting on the room stat, to prevent any future freeze ups.

[Andrew Gabriel]

You need to drain down tanks and heating system (if it has central heating), if you aren't leaving it running in frost protection mode. That's probably a condition of any insurance.

Turning off the water will limit the volume of water damage to the tank(s) full if they come through the house as a result of a burst pipe, but you could also damage a lot of the pipework and heating system if the residual water in them freezes.

Might make sense to arrange to visit at same time as a plumber, so he can do this for you if you aren't sure. There may already be some damage which needs repairing too.

How long is the house likely to be empty? I would suggest leaving the electricity on with some lights on timeswitches for security purposes.

[SS]

Thanks for the replies.

The house could be empty for a month maybe 6 weeks. I should have mentioned its a combi heating system. I think I have the jist of what to do ie drain as much water out of pipes and (I think) drain the combi boiler system. As far as I am aware there are no header tanks due to combi system. I suppose one problem will be if pipes frozen it wont drain :-(

Dreading this visit tomorrow. At least if I get the mains off it should limit damage if a pipe has burst but frozen.

[george [dicegeorge]]

my plastic inlet pipe in the attic froze, then the water level in the tank went down (cos not refilling) then the float valve thing float down a bit then the inlet thawed water poured into the tank and it overflowed because the float valve thing was frozen open, it woke me at 3.30a.m. on christmas day the waterfall thundering down the stairs!

and i hadnt turned off the main supply so if i hadnt heard it it would have poured down all night!

[g]

[george [dicegeorge]]

which reminded me to nip down to the cellar and turn it off again so it wont happen tonight!

[ransley]

I would heat the house back up, make sure all faucets flow, then drain everything even the heating system. For a short period it might be better to just heat it as draining a heating system and refilling can be a big job to remove all air from radiators and pipes, and unless your house is set up right draining the water pipes can be hard, and the water heater?.

[TheOldFellow]

What everyone else said. Consider some form of background heat in the core of the house, I use an electric (yes, it means that's on - but you probably need it for security lights) heater designed for a greenhouse - it has a thermostat designed for low temperature switching

- 1200 watts, but only on when temp falls below 1C. It's amazing how little energy is needed to keep a moderately insulated house frost-free.

R.