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harry harry is offline
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Default How long does it take to thaw out an underground pipe?

On Dec 30, 2:53*pm, TheOldFellow wrote:
On Thu, 30 Dec 2010 14:08:32 +0000





Tim Watts wrote:
TheOldFellow wrote:


My previous thread about my frozen supply pipe elicited no helpful
suggestions, frankly just as I expected. *There just isn't any way
to thaw out a pipe in the ground.


So now it's 4 days later, and the air temperature here has been
above 4 for all that time, even at night, and most days above 6.
Pits dug around the garden in the likely places have not found the
pipe yet, but do confirm that the ground is NOT frozen now - at any
depth.


I've checked that the stopcock in the road is OK, and that there is
nothing impeding flow at the house. *The pit was full of ice on
Monday, but has been clear since I cooked that out with boiling
water.


Does anyone know how long it will take to thaw a pipe, or does this
sound like a 'hire a digger' job?


Much appreciate some help on this, as watching SWMBO with the
bucket of her head going to the village pump is getting boring.


R.


How cold did it get in the air and roughly how long?


Not sure as I was away from Thursday to Monday. *Last week was very
cold, -13.5 on Monday night, and people say that it was -11 on
Christmas Eve (Friday). *I don't think it got above freezing in the air
from Monday to Sunday (Boxing Day)



My supply is 2' down and have never frozen though the top layer of
the ground does freeze for some random depth - probably a few inches.


I suspect as you found ice in the stopcock pit that that is where the
freezing took place.


Can you pour some more boiling water down there?


It has water welling up through the gravel at the bottom of the pit, so
the hot water cools almost instantly. *The pit is only 15 inches below
road level. *It's a rural lane. *We're in North Cumbria here.



If the ground is now unfrozen at any depth, the pipe should follow
suit - the difference being the ground is not solid water/ice so has
a lower amount of heat per cubed required to thaw it. The pipe if
frozen of course may take longer but it is only a small diameter.


There is quite of lot of ice and snow on the roads round here still,
especially where the sun never reaches. *My garden is shaded just where
the pipe would run (I think). *I can't check below the paths, which is
where the pipe might run, and they are in the deepest shade.

I'm definitely thinking replacement with a trace heater for next year.
Even though it does mean trenching through the tarmac drive. *Good
excuse to buy a big angle grinder

R.- Hide quoted text -

- Show quoted text -


The biggest problem with underground pipes is not freezing but ground
heave due to frost. A joint may have broken. The water you mention in
your stoptap pit may point to the problem. If there is unfrozen
groundwater it doesn't sound like your pipe has frozen, more like
broken. What you need is a listening stick and starting from the stop
tap listen for the leak. Works well on the pipe and hard surfaces
thought some experience helps. A big screwdriver can be used but not
as good. Press blade onto stoptap and ear against end of handle and
listed for hissing noises. Press hard.