# Unfreezing Underground Pex Lines



## Eric Johnson (Mar 5, 2014)

My mom ran out of wood for her OWB in Wisconsin in mid February, and since I was planning to go there in early March (now) anyway, I suggested she shut down the wood side and heat with (very expensive) propane until I could get out there and cut up some dry, dead oak logs that I didn't get around to cutting last fall. I figured, back then, "Heck, it will probably be another mild winter and she'll be fine until March." Well, no dice.

We decided that instead of draining the boiler, she would keep small fires going in the firebox just to keep the thing from freezing. Foolishly, I assumed that there would be enough convection through the underground lines between the house system and the OWB, with the circulator turned off to save on gas, to keep them from freezing up.

Well, I was wrong. Frozen solid by all appearances. A friend suggested getting some piping or tubing smaller than the 1" pex, connecting it to the domestic hot water, and slowly feeding the smaller diameter pipe into the bigger one. Blast the ice directly with hot water. Melted ice and domestic water would flow out the end of the bigger pipe, and into a 5-gallon bucket. That was much better than my own idea, which was to buy a salamander-type propane heater and try to blow enough hot air into the piping assembly to (eventually) thaw it out. Dubious idea at best, with 70 feet of frozen-solid run buried about a foot under a plowed section of the yard.

So, I stopped at Menards on my way from the airport and picked up 100' of 1/2-inch pex and a hose bib adapter. It took about three hours to clear the return line--making steady progress the whole time--and about half an hour to break through the supply line. I have no idea why the discrepancy, but after pushing on that plastic pipe for 3 hours, I wasn't really interested in doing it all again. But I would have.

Anyway, bottom line is that we were heating with wood again by 10:00 p.m., so it was all good.

Don't know if this technique has been discussed here recently, but I highly recommend it as a cheap, effective and relatively fast solution to what may be a common problem this winter. And it's pretty much guaranteed to work.


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## Fred61 (Mar 5, 2014)

Hot water is the best way to de-ice. In fact I (tongue in cheek) made a bet with a friend that I could pee through a particular block of ice faster than he could burn through it with his 140,000 BTU torch. This was on a day that he was trying to thaw out a culvert and he scoffed at my suggestion to use hot water.


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## Bob Rohr (Mar 5, 2014)

Fred61 said:


> Hot water is the best way to de-ice. In fact I (tongue in cheek) made a bet with a friend that I could pee through a particular block of ice faster than he could burn through it with his 140,000 BTU torch. This was on a day that he was trying to thaw out a culvert and he scoffed at my suggestion to use hot water.




We had to thaw suspended sewer lines in underground parking areas below condos from time to time.  We used 1/4" soft copper tube connected to a steam cleaner.  It doesn't take much of a hole in the ice plug to get them flowing and thawed. 

Need fast reflexes when the s---  hits the fan, so to speak, cut in a Y fitting first, push the copper in a small hole in a cleanout plug.

Glad you got it thawed, I have seen pex split when left frozen for extended periods.


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## Eric Johnson (Mar 5, 2014)

Yes, lucky as usual. As for the fecal matter hitting the fan, I started to worry about how I was going to handle the hot water when I finally broke through (left the valves on the boiler open), but then realized that it was only about 80 degrees, so I got a warm soaking before getting the pex reconnected to a valve. Not a big deal. I was also thinking that steam would be even better, and possibly even some kind of attachment to a pressure washer. But hey, it was cheap, relatively easy and it worked, so I ain't complaining.


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## FTG-05 (Mar 5, 2014)

Forgive me, I'm from the south:  Why don't these systems use antifreeze instead of just water?  Is it an efficiency issue or.... what?

I'll bow out, not my problem, we have to deal with subartic 40 and maybe 30 degree weather (Those are positive numbers....)  all the time.....


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## MarkW (Mar 6, 2014)

FTG-05 said:


> Forgive me, I'm from the south:  Why don't these systems use antifreeze instead of just water?



Most areas would require eco-friendly propolyne glycol rather than ethylene glycol.  In sizeable quantities, both are quite an expensive additive with the former coming in at $750/55 gal barrel last time I had to purchase several years ago.  And at a 50/50 mix, you could see your costs rising quickly depending on your system volume.


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## mr.fixit (Mar 6, 2014)

The frost depth is reportedly 6ft+ down under areas with no snow cover.
A lot of towns in the area have all citizens running a stream of water 24/7 to keep water mains from freezing.


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## flyingcow (Mar 6, 2014)

I've used my steam cleaner to do the same thing. A little hot water goes a long way. Once I rented a rig that had 1/4 inch plastic line that was hooked to a modified propane cylinder. This sat on top of a turkey cooker. You know the ones you deep fry a turkey on? Put a gallon or two of water in Small tank. Heat water up to a few pounds open hand valve and push line thru frozen pipe. Slick when you have no running water.


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## mike van (Mar 6, 2014)

Some years back I made a 'steam thawer' from a large old pressure cooker, about 100' of 1/4" synthetic hydraulic hose, and one of those propane flame throwers that Northern sells.  Worked like a charm on a 90' run from a spring that wasn't buried quite deep enough.    MarkW - I'm wondering if the circulator was just wired on on your moms system if it would still have froze?  The moving water theory, you know?


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## arngnick (Mar 12, 2014)

I will have to put this idea in my back pocket...sometimes people shy away from pex or other plastic pipe in the ground because if they freeze they are very difficult to thaw. THANKS


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