Copper Pipe Freezing Underground


  #1  
Old 03-07-11, 02:58 PM
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Copper Pipe Freezing Underground

City water line is 3/4" copper. Since installing an 'energy efficient' heat tape it is freezing just below the ground.

Getting nervous after reading this:
============================================

Freezing

Hard-drawn copper tubing will burst as readily as iron pipe when it freezes. Soft, annealed tubing, however, is much more hardy. Smaller sizes can freeze half a dozen times before they are so weakened that they burst. The sizes over one inch may withstand a dozen freezings without mishap.
=============================================

I have the soft annealed and I know this has froze at least 4 times. This last time I put the heat gun to it where it goes in the ground and it was flowing in less than a minute so not much ice this time. Need I worry here? Nothing could ruin my day than to have it freeze and break in the middle of the winter....that would be bad, real bad.

So, I'm thinking of digging down 3 feet or so this summer and put some underground heat tape on it. Found a place in Canada that makes it but boy is it pricey....they will make a 5' piece but have to charge for 10'......$185.00 YIKES.

So, should I cut off the top 3' of copper and replace with new to be on the safe side?

Guy that set this up has the water and sewer lines right on the outside edge of the trailer rather than the middle so the ground will freeze. Idiot.

Any cheaper suggestions welcomed.

Thanks
 
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Old 03-07-11, 03:10 PM
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I was thinking of putting 2" Styrofoam in the ground but what I've read this will still let the frost go down a foot or so. Well, that's where it is freezing.
 
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Old 03-07-11, 03:18 PM
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Where is that quote from that says it is ok to freeze soft copper tubing ?
I have repaired many pipes that froze and broke the first freeze so I wouldn't bank on those suggestions.
Only three feet down in Minnesota?
You are not that far south of us and we bury at a minimum of 8 feet and more in some cases.

If you only need five feet of heat tape is this for above ground?
If so you could use self regulating heat tape and cover it with insulation.
Not sure how much you pay for water but it is common here in frost prone areas to install a small bleeder line and constantly flow a small amount of water down the drain.

What exactly is an energy efficient heat tape?
Make and model would help.
 
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Old 03-07-11, 03:55 PM
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Where is that quote from that says it is ok to freeze soft copper tubing ?
I don't think it says it is okay, only that it can take UP TO so many times freezing. I'll have to look it up.

Only three feet down in Minnesota?
Frost here is 6'+ but mine seems to be freezing near ground level. I'm sure if I didn't use water for a couple days it would freeze all the way down. I just don't want the dig that deep in pure red clay.

No water meters here so everyone pays the same no matter the use. I could let it run but it seems such a waste of treated water.

What exactly is an energy efficient heat tape?
In the good old days the heat tape thermostat was outside the insulation. When the air temperature was below 40 it would turn on and stay on. Using no water overnight, when you flush in the morning and feel the copper tubing to the toilet it was HOT. I'm guessing the water was so hot it kept it thawed just below ground level.

Energy efficient has the thermostat under the insulation that monitors the temp in the pipe, not the outside air. It only comes on for a couple minutes then shuts off.

The tape is made my Easy Heat.

If you have any suggestions I'd love to hear them.

Thanks
 
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Old 03-07-11, 04:17 PM
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Here's the link to the freezing question....

Using copper pipes in plumbing

I don't see a date.

I would guess I have type K from the street which seems to be a good thing.......

Type K

Its bursting pressure is high: 3/4" Type K copper tubing has a bursting pressure of more than 5,000 lbs. per sq. inch.
 
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Old 03-07-11, 04:34 PM
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Easy Heat has many different types of heating cable.
Exactly which one do you have?
EasyHeat Pipe Tracing

It is most likely that your new heat tape is self regulating and the old one was the resistance type.
You can get self regulating heat trace in a range of between 3 and 20 watts/foot but the ones sold in retail stores are generally the lower wattage types.

If you still have the old heat trace you can compare the wattage to what you have now and you might find a fair difference between them.
If you have self regulating it won't have a thermostat as such, the output depends on the surface temperature of the pipe it is wrapped on.

You do have it wrapped securely and tight with no air gaps right?
 
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Old 03-07-11, 05:04 PM
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I have the AHB016 with a thermostat against the pipe.

The old one was installed maybe 20 years. Slim blue stuff with a thermostat the had to be outside the insulation, in free air. No ground on the plug. Really old.

I can't compare, the old one burnt out.

Yup, wrapped with yellow insulation with vapor wrap on the outside.
 
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Old 03-08-11, 05:16 PM
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I did some more reading then gave Easy Heat a call about their SR Trace tape. Their ad says it is approved for wet or dry conditions. Well, the guy says it isn't approved for underground-YET! Wish I would have asked him about the yet part. If you can put this on your roof (SR51J) covered in snow and ice I don't see why you can't put it underground.

My plan: dig down 3 or 4 feet, spiral the cable, cover with closed-cell foam insulation, surround this with fine sand and bury. Seems to me the worst that can happen is the tape shorts out and quits working, I'm sure the dirt won't catch on fire as this will all be underground. No rocks either, just clay.

Thoughts Greg?

Thanks
 
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Old 03-08-11, 07:04 PM
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The cable used for roof de-icing is the self regulating type and although the cable is moisture resistant, the connectors are not.
The cable you have is the resistance type and is fairly delicate.

If you were to look at the element inside the cable it looks as fine as coarse hair.
I don't think that even if insulated it would stand up to being underground.
Because the element is in series starting at the plug, traveling to the end and back on the other side of the cable, one nick will kill it.

You could remove the insulation from the sensor and lossen ot slightly from the pipe.
It is possible that the spot you are sensing warms up quicker than the place where freezing starts.
 
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Old 03-08-11, 07:41 PM
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I'm sorry. Guess I mucked this up talking about too many cables.

The cable with the thermostat is for above ground, works fine so forget about that.

The question is about the below ground. I'm thinking of buying this:

http://www.easyheat.com/PDF_Files/_f...R_appGuide.pdf

The heating part would be below ground but the GFCI and plug would be high and dry.

Hope that makes sense.

Thanks
 
 

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