Defrosting pipe?

[Steve]

Due to the current cold weather, I suspect we may have a frozen pipe. Washing machine connected to end of pipe gives an error when switched on. We have an outside tap which freezes every year, and I suspect ice from this has backed up into the pipe causing a blockage. Since there is no circuit and the pipe terminates at the washing machine fitting, there is no circulation of water to prevent freezing. The washing machine is in an uninsulated utility room which would get fairly cold...

Schematic as follows, --- represents cold water piping.

--------------------------------------------------------------------- ...........¦.........................¦............................¦.....................................¦ .........Sink.............Dishwasher.......Outside Tap Loop..........Washing Machine

How would I remedy this problem, the only really accessible section of the pipe is the outside tap - of course I can get to more by removing appliances, but it may be less hassle to wait until it defrosts naturally, given the current state of the utility room and things stored within ;)

[Ian Waddell]

.. .............................

Have you tried putting a blowtorch on or leaving a candle/flame under the accessible part of the pipe. Assuming you have copper pipes, the heat will conduct along the pipe and dissipate and this should work. You could also pour a kettle of boiling water over the pipework (but this will leave surrounding ground slippery when it freezes). The only problem you might have is if the freezing water has cracked the pipe - in which case you'll end up with a leak when it thaws.

Ian

[js.b1]

First, find your stopcock (and verify it turns off :-)

If you can - lag the internal pipe. Armaflex is well regarded, closed-cell not hygroscopic leak cheap stuff, available with 9mm 13mm 25mm wall. Plumber's Merchants, Online & Ebay carry it.

If you can - fit an internal stopcock. Reroute the pipework so you can fit an internal pegler 1/4-turn or conventional stopcock to the outside tap so it can be isolated.

Lag the outside tap & pipework. This insulation needs to be UV proof & waterproof, conventional armaflex being nitrile rubber is not suitable because it breaks down with UV, there is a version which is suitable and "tap insulation packs". Some people like to use a large core drill and drill a much bigger hole than the pipe, then sleeve the wall so any leak can not get into the wall cavity, and surround the pipe in 25mm wall Armaflex. Do not use expanding foam, it takes on enough water to possibly encourage freezing rather than deter it. Insulating the pipe in this way gets heat conduction from inside the house down the pipework to limit any freezing to the outside and confine any burst to outside.

You can get quite cheap tube heaters, often with an IPx4 rating re splashproof re wet washing in a utility room. It might be possible to locate such a heater as to prevent pipework freezing or keep the room above 5oC. If it can be insulated then it is worth doing, that may simply be a case of screwing a panel of insulation backed plasterboard to the wall.

[Tim Lamb]

In message , Ian Waddell writes

Hair dryers have multiple uses.

I generally use an old B+D paint stripper.

regards

[Steve]

Have you tried putting a blowtorch on or leaving a candle/flame under the accessible part of the pipe. Assuming you have copper pipes, the heat will conduct along the pipe and dissipate and this should work. You could also pour a kettle of boiling water over the pipework (but this will leave surrounding ground slippery when it freezes). The only problem you might have is if the freezing water has cracked the pipe - in which case you'll end up with a leak when it thaws.

Ian

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Have resolved the problem - , tipped a cup of hot water over the outside tap and it started running cold, turned off the section of pipe via the stopcock and tightly wrapped a plastic bag round the base of the mixer tap to stop the water coming out - turned on the outside tap and turned on the mixer hot tap so the pipe was flushed with hot water until it started coming out of the outside tap - which also melted the blockage through to the washer.

[Mike Buckley]

In message , Tim Lamb writes

I had to dig my paint gun out of the garage to defrost a pipe last night. Got home to find that the waste outflow for the washing machine had frozen up, so we had a kitchen floor covered in water. The pipe is shared by the condenser piper from the boiler but is big enough that it hadn't affected the boiler by the time the washer came on.

No lasting damage hopefully.

[Invisible Man]

So you backflowed hot water into a mains cold water pipe. Not sure that meets plumbing regs. Water company would say that any bugs could find their way back into the main and kill everyone with a water supply from the water treatment works. PANIC!