Frozen Pipe

Hindsight would be marvellous - but is in short supply....

We've been out of the country for over three weeks so the very cold weather was not expected when we left.

I turned down the boiler so it was still putting heat around the house ... just in case.

On our return we weren't greeted with aburst pipe, but a frozon pipe between the boundary box in the pavement and the house.

The Water Co. suggested waiting for it to defrost and suggested pouring a bucket full of warm water of the meter/stopcock to get some heat in that end, is ther anything more that I can do?

The house is built into the side of a hill with the living accomodation being upstairs and the bedrooms/bathroom downstairs. The boundary box is in the pavement at the upstairs level, and the pipe then says sub-surface and enters the house through the bathroom floor

- the internal stopcock in behind the bath.

Other than puilling up carpets and floorboards and trying to find a frozen pipe and gently defrost it if possible is there anything to bo done?

We've got hotwater in the tank - could I connect the hot water to the cold and back feed some warm water into the cold system to try to get to the frozen bit...?

Helpful tHoughts please

Ta

Steve

Reply to
Steve Bilton
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Not unless you have some means of raising a pressure greater than the mains and it would be illegal to back feed the mains that way as well. Contamination of water supply etc.

Is the service pipe plastic or metal? I've heard about people in Canada with a metal service pipe finding some one with a welder generator connecting one side to the exterior stop tap and the other inside and running the generator for a bit to warm the pipe... You'll need good secure connections mind.

How deep is the pipe? And where are you it has been cold but only really cold for a long time ina few places. If the pipe is 500mm down or so and your are in one of the warmer parts of the country I suspect that it has frozen at the relatively exposed stop tap rather than in the buried pipe run itself, unless that gets close (300mm) to the surface.

A kettle of boiling water over the stop c*ck might do it, that's easy way of getting a decent amount of heat down there.

Reply to
Dave Liquorice

Back in the days of nationalised water companies and metal water pipes, they would come along with very low voltage very high current power supply, connect it to each end of your supply pipe, and pass a current through it to heat the pipe.

In your case, the pipe is most likely frozon in a section which isn't underground, e.g. if there's a section under a suspended floor. That's going to have frozen before an underground section. However, the underground stopcock is another candidate, as there's access through the ground.

Reply to
Andrew Gabriel

This is correct. Pipes are 'regulation laid' a half meter or so underground.

Danger is when they rise up above ground. If you can get a fan heater blowing into an under floor space, that should sort.

Reply to
The Natural Philosopher

During the winter of 1963/4 many pipes froze between the stopcock outside and emergence within the house. Fortunately in those days lead was the comonly used material. The solution was to employ a "Bantam" welder with long leads, clip onto the stopcock and the house pipes and run about 50 amps through the pipe for a few minutes to warm it up. If you have plastic pipe you cannot do this unfortunately!

Reply to
cynic

Use a welder or turn up boiler aquastsat and hope it didnt rupture. Keep an eye on boiler water level hourly until you are sure you wont leak out all the water and ruin the boiler, I wouldnt run it at night without checking it often until I was sure pipe wasnt leaking, mark the water level now, and after it heats up.

Reply to
ransley

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D Is the service pipe plastic or metal? I've heard about people in Canada** with a metal service pipe finding some one with a welder generator connecting one side to the exterior stop tap and the other inside and running the generator for a bit to warm the pipe... You'll need good secure connections mind.

BTW** Often now illegal in some Canadian cities due to it causing houe fires!

Many years ago I buried a loop of number 6 AWG (American Wire Gauge) above the plastic water line from my well to he house.

However due to it being at least four/five feet down it has never frozen. The idea was that if freezing ever did occur, to run a heavy current from a transformer or welder through the wire (probably for a day or so) and gradually warm up the ground near the pipe. Now use that wire loop as an extra ground connection.

By the way is there any way one could disconnect the incoming pipe; poke a smaller diameter plastic hose back down the pipe to the location of the freeze and with a funnel pour boiling water to thaw it? I think also read about someone who made up a device that put steam out through a long thin pipe that was pushed back down the incoming water main. Maybe even warm house air blown down the pipe through a small hosetaped to a hose vacuum cleaner would do it? Stand by once it lets go!

Reply to
terry

BES carry an underground blue pipe duct (cheap) with insulation to go in it (expensive) for shallow burial depth - it is water industry approved; the insulation is obviously waterproof and very thick (100mm outer diameter of the duct). Insuduct or similar (they do an outside water inlet box permitting an outside stopcock, although myself I'd want heat tape on it too!).

Current regulation is I think 750mm depth which might not always be possible/practical for some people.

Reply to
js.b1

Steve Bilton explained :

Very dodgy advice, but needs must....

Passing some current through the pipe or the water will warm it up. It should work whether the pipe is metal or plastic, but on a plastic pipe you will need to connect to the metal fittings at either end of the pipe which are in contact with the water/ice. A car battery or a similar low voltage supply should do it, but you will need to be careful.

You must not try to force hot water back into the mains, that would contaminate everyones water supply.

Reply to
Harry Bloomfield

conductivity of tap water 0.0005 to 0.005 S/m or 200 to 2000 ohms per metre. I cant see a 12volt car battery doing much warming with plastic pipe

Reply to
cynic

Just a brief update...

Having read the initial replies, I thought that I should answer a few questions.

We live in the north of Exeter - Devon - reportedly down to -11degC last week, and well below 0 this week.

Pipe material - unknown as it is unseen in the boundary box hole, and unseen inside the house. The bathroom is in the middle of the ground floor of the house - it's built into the side of a hill so living accomodation is upstairs - the internal stopcock is accessible but under the bath, behind a completely tiled wall - I ripped the skirting board off to see if I could get some warm air at the pipework but the wall is tiled to the floor, then the skirting is added purely to finish off (now got another job to do to put that back - SWMBO was not impressed!)

There are no access holes to the under floor areas - afaik - all under either carpet which I am loathed to lift, or bathroom floor tiles which swmbo is not even considering lifting!

Anyway, I thought that I would start the day by putting a washing up bowl of warm/hot water into the boundary box, this filled it and it took a while to drain, once it had another went in.

About 2.5 hours laters, whilst on the phone to the Insurance to see what they wanted to say, and there was a gushing of water from the bath tap that I had left open just in case - so job done.

I checked the meter once all the toilets and tanks had taken their fill, and all was motionless - result.

Thanks for the help guys.

Steve

Reply to
Steve Bilton

There's one I may need to replace at some point. Since it would have to be buried only about 400mm from an outside wall with little foundations (built 1905), digging a 750mm trench would bring the house down. Have wondered how to do this, and would certainly factor in some type of heating tape. A length of 1mm T&E, all conductors shorted at the far end would probably do it.

Reply to
Andrew Gabriel

Cut a thick polystyrene plug to put in the access hole for the tap, to help insulate it. New outside taps come with one.

Reply to
Andrew Gabriel

TLC do some heating tapes, but I suspect they are for internal use only. Worth using heating tape on the bit before the stopcock in the house though if you have solid walls and limited heating the other side (you can tell how I am going to break Part P at some point :-)

An alternative would be to run a pipe in a pipe - with T-junctions at each end. Seal the T-junction to the pipe and run pipe up to ground level (or meter-type-box) with plugs in. Should the pipe freeze you can just pump warm water around in a loop until defrosted.

I suspect the insulation would negate the need, 100mm of closed-cell insulation around a 25mm pipe is quite substantial at least in stopping it icing up completely. Armaflex is 6-13-25mm with 25mm being the ideal I believe. Note whilst the duct & couplers are cheap, the approved insulation is expensive (about =A3200 for a typical run). Then again digging 750mm isn't cheap - not as easy as 450mm with a pick for a cable.

One area people seem to have been caught out on is HW pipes freezing, water only drawn occasionally throughout a day unlike CW. I've not seen Floodcheck Automatic mentioned for HW protection, but something like that might be useful - some ability to meter say 200L in one go and then shut off, they do a washing machine valve like this (impellor spins, self resets if less than NN-Litres drawn).

Reply to
js.b1

Andrew Gabriel wibbled on Friday 15 January 2010 14:00

It's not a problem - take the trench upwards to a more sensible level for the last couple of feet next to the house. You wont need heating tape, though if you are really worried, placing some insulation (waterproof) around the pipe won't do any harm.

My house sits on a concrete trench foundation all of about 6" thick and it starts one brick course below the top of the ground.

I took a new water pipe under that and up through the kitchen floor last year.

Right - just measured mine. The MDPE pipe is all of 56cm below ground level (same as the original main), here:

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's now in a brick lined chamber with a small round metal lid on top - primarily so if that joint fails I'll know about it, rather than it silently washing the soil out from under the house...

Anyway, I didn't even bother with insulating the metal chamber lid (though I should) and no hint of anything freezing. The pipe is now submerged in 3" of fresh meltwater (though normally it is above the water table) which is why the incoming mains is now rather cold, but other than that no issues with the house or the pipe.

What I did was to make the smallest tunnel I could get away with sideways under the foundation strip. This met a core-drilled 3" hole I made going downwards through the kitchen floor.

I inserted a 110mm rest bend, extended with 110mm pipe to lead to that chamber, under the house with the top of the rest bend pretty much level with the underside of the foundation strip. The top of the rest bend was pre fitted with a solvent weld 110-50mm reducer (offset type) and I dropped a bit of 50mm waste down through the floor pre-coated with solvent weld and shoved it in the joint.

I then back filled the pipe under the foundations with strong concrete, doing as much as I could to ram it in under the foundations and around the pipe. The sides of the tunnel were fairly solid and undisturbed clay.

I then fed a length of pre-warmed MPDE down the kitchen floor hole, and it popped out in the pit without much trouble. After jointing and testing, I finished the pit off.

OK - I will have to have 2-3 courses off the top of the pit if I need to work on that joint in the future. I'm not expecting to. But, I didn't want a massive manhole cover either - it really is for inspection purposes only. If the joint were > about 3m from the house, I wouldn't have bothered.

HTH

Tim

Reply to
Tim W

Collect the gases given off and burn them. Maybe they have cold fusion electrodes so you get lots of heat?

Reply to
dennis

Also intended for industrial use, i.e. money not a significant object.

Soil heating cable (better garden centres) is cheaper, although it tends to come pre-terminated (i.e. pre-chosen lengths).

Reply to
Andy Dingley

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