Ice in conduits

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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.
 
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.

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

GoldDigger said:
You might also thread a small diameter PEX pipe in and pump heated water through it.
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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 :D. 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.)
 
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.
 
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.
 
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
 
winnie said:
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
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But beware of the other common antifreeze, ethylene glycol, which is extremely toxic to pets, who lap it up because it tastes sweet.
 
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.
 
Dzboyce said:
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.
Click to expand...

A steamer might work for 20-30' but would probably have trouble with 100' (maybe a high-temp pressure washer?). It all really depends on how much of the underground conduit is full of water- if my calcs are correct, 10' of 2" pipe holds around 3.5 gallons of water. I'm not going to calculate the heat of fusion for that, but as anyone knows who's defrosted a roast in the microwave, it won't be trivial.

Warm glycol or methanol might work, but again, it depends on how much ice there is to melt.
 
Again, these are all great ideas.All conduits have pull strings and I think that alcohol will wick its way down the string, we will see and report sucess or plan B or C....The hot engine exhast is also interesting. Thanks.
 
Steam, only way to go, then drag rags through it till they are dry. Thawed 500' of 4" PVC in 20 mins with a steam on wheels company. Hot air is a waste of time Glycol might work but not as clean as steam.
 
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