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Thread: Ice in conduits

  1. #1
    Join Date
    Oct 2005
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    Interior Alaska
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    Ice in conduits

    Last fall prior to freeze up we ran several underground conduits for spring work. Although we taped the ends of exposed stub ups, some of the runs have ice blockage. Has any body used antifreez or methonal to thaw out conduits, would eather be detramental to XHHW insulation? I plan to blow warm air throgh the runs once the there is enough clear to allow air. I can also pull a mouse to clean out nearly all moisture once thawed. If i wait untill soil is thawed to 24" it will be July...(interior Alaska). Conduit is 2" PVC 150-200ft runs.

  2. #2
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    You might also thread a small diameter PEX pipe in and pump heated water through it. Hopefully this would clear the ice blockage and allow you to dry out the conduit with heated air before it can refreeze.
    Just dumping hot water into the open end might not get the heat to the ice blockage, and just leave a larger block of ice.

    Sent from my XT1585 using Tapatalk

  3. #3
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    Just dumping antifreeze or methanol down won't help much or quickly, and you have potential hazmat problems.

    Quote Originally Posted by GoldDigger View Post
    You might also thread a small diameter PEX pipe in and pump heated water through it.
    Could use a garden hoses or 1/2" tubing; and water doesn't have to be hot, just warm. I'm imagining a washtub with a sump-pump, an immersion heater, and about 200' of hose. Would also need a collar/tray around the stub-up to catch the water and drain it back into the tub. Keep feeding in hose until it stops, back off, try again in 10 minutes. Be ready to suck all that water out quickly when you get through . This does not sound like fun.

    Is this all outdoors?

    Might be interesting to know how much of each one is blocked (run a snake from each end). If it's only a few inches a sharpened plumber's snake might chip through the ice, then you can blow hot air through. (If the whole thing is blocked, wait for July.)

  4. #4
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    I've used methanol and had good results. If it's not a big pipe a couple bottles of gas line antifreeze is a handy way to get it in there.
    If you go and decide to dance with a gorilla the dance ain't over till the gorilla decides it's over.

  5. #5
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    Oct 2005
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    Thanks for the input. Gas line antifreez (Heet) was what I had in mind or methonal alcohol used for injection into truck air brakes. Glad to know this has been used. Don't expect large amount of ice, but we will find out. will post results. Also the alcohol boils off fairlly fast.

  6. #6
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    If PVC conduit, dump salt water into it. Might not want the corrosion issues if metal conduit.
    I live for today, I'm just a day behind.

  7. #7
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    Dec 2016
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    Royal City, WA
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    I use steam inside frozen water lines. I’ve adapted a drywall steamer to a roll of 3/8” polyethylene tubing. I slowly pushi it into a frozen water line till I get thru the blockage. A couple cups of water might thaw out 10-29 feet of water line. Warm water would work, as mentioned previously, but could be a LOT of work to get a recirculating setup going.

  8. #8
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    Propylene glycol would likely not be considered a hazmat if used. It is non-toxic in reasonable quantities (more toxic than ethanol, but safe enough to consume small amounts), it is readily water soluble and readily biodegraded. Commonly sold as antifreeze for potable water systems.

    However I have no experience with the application described. I think that heat (hot water, hot air, or steam) would be a better tool.

    -Jon

  9. #9
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    Quote Originally Posted by winnie View Post
    Propylene glycol would likely not be considered a hazmat if used. It is non-toxic in reasonable quantities (more toxic than ethanol, but safe enough to consume small amounts), it is readily water soluble and readily biodegraded. Commonly sold as antifreeze for potable water systems.

    However I have no experience with the application described. I think that heat (hot water, hot air, or steam) would be a better tool.

    -Jon
    But beware of the other common antifreeze, ethylene glycol, which is extremely toxic to pets, who lap it up because it tastes sweet.

  10. #10
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    I would try hot air through a hose before adding more liquid. You could even use vehicle exhaust as long as it's not enclosed.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

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