Winterizing a dead-end water pipe.

[KadeC]

Hello, we're close to Billings Montana where it can get -30 degrees in the winter. Our situation is this:

We removed a rusted out automatic horse watering trough and capped off the water pipe. This 1" water poly water line comes up vertically from the ground and is surrounded by a 6" pvc pipe "shaft". this shaft is probably 6' deep. The end of the piping is capped off with a galvanized plug and is pretty much even with the ground surface. There is no sub surface way to shut off or drain this end of the line piping

The water line first leaves our well pit, runs about 50' to feed a self draining bury pipe spigot, than runs another 50' to another bury pipe spigot, then runs probably 30' to the dead ended plug

The old water trough had electric heat. Unfortunately we had to remove the electric line that went to the trough area, so electronically heating the end pipe is out of the question.

I did consider shutting water off to this entire system for winter, un plugging the pipe end and siphoning out the water at least down to the 6' level, but we need to leave the 2 bury pipe spigots operational .,.,so of course the pipe would refill with water

I've thought maybe I could do this:
1) shut off water at well pit source to depressure water line.
2) un plug dead end, siphon out water (at least down to the 6' depth area)
3) fill emptied pipe with antfreeze and re plug
4) slowly turn water back on
5) the water pressure will "push" against the antifreeze and "hold" it in the last 6' of pipe, preventing it from freezing
6) the 2 bury pipe spigots will be operational (and of course self drain)

Will this plan work?
Thank you in advance!

 

[Reach4]

I am not a pro. I have never tried any of the ideas I describe below. I think your idea of putting RV antifreeze (not poison) into the pipe has a good chance of not working due to mixing. Best is to dig down, and put in a frost-free yard hydrant now.

But if I were to try your antifreeze method, I would find a rubber stopper that was a tight fit. You can order these in different sizes. Order more than one, and start with the biggest. Shove it down to the elbow with a rod. Then pour your RV antifreeze, and cap. An alternative would be to make a plug out of wood, and shove that down. Wood expands when wet. In nice weather some day, dig down, and cut away the stoppered pipe. Then put in that yard hydrant.

 

[Sponsor]

 

[KadeC]

I am not a pro. I have never tried any of the ideas I describe below. I think your idea of putting RV antifreeze (not poison) into the pipe has a good chance of not working due to mixing. Best is to dig down, and put in a frost-free yard hydrant now.

But if I were to try your antifreeze method, I would find a rubber stopper that was a tight fit. You can order these in different sizes. Order more than one, and start with the biggest. Shove it down to the elbow with a rod. Then pour your RV antifreeze, and cap. An alternative would be to make a plug out of wood, and shove that down. Wood expands when wet. In nice weather some day, dig down, and cut away the stoppered pipe. Then put in that yard hydrant.

Reach, I too am concerned about the "mixing" and diluting of the antifreeze (if I didn't utilize the "plug" scenario) BUT...maybe, just maybe the water pressure would "hold" the antifreeze in place (last 6' of pipe). I also was going to use straight automotive antifreeze but you're right, I should us non toxic RV antifreeze.
Right now, I covered the pipe with a straw bale, thinking that this will trap the ground heat to help keep the pipe from freezing....so far it's survived -3 degrees.
Thank you and I'd love to hear other comments

 

[Jadnashua]

You really don't want to put antifreeze in a line that will be in use, and especially not automotive stuff - it's toxic...it doesn't take much to make you or an animal sick or even kill them. The RV stuff is designed to be put in traps, not supply lines (which can be drained more easily). That way, even though it's not toxic, you wouldn't be mixing it because it's in the drain verses a supply line. The non-toxic part comes in when you drain it...automotive stuff is considered a hazardous waste...the RV stuff isn't, so it can be flushed down the drain without major issues.

If you ever want to reuse that line, you really need to go down below the frost line and cap it or reinstall a (new?) electrical service that could try to keep it above freezing. Ideally, you'd use a yard hydrant with the shutoff below the frost level that can drain when not in use.

Trying to dig a pit that deep to do the work this time of year won't be fun. Hay's a fairly decent insulator, but you'd need to go around that area since it would not trap enough heat if you didn't. Probably out to at least 6' around, and if the stuff got wet, it would lose most of its insulating capacity.

 

[Gary Swart]

You must drain the line. Insulation does not provide warmth it only slows heat transfer. One way to drain the line is with air from the pump area, Of course the water must have a place to go when the pressure is applied. The only other way is to dig down to the end of the pipe and either just leave it open or install a stop and waste valve with a pipe to the surface for a curb key.

 

[LikeABigFriedEgg]

Hmmm ... well six feet down, the ground is warmer than freezing---what, maybe 50 degrees?

What is between the PVC pipe and the water pipe? Air? If so, close the top of the PVC pipe so that the air can't leak out, and the water pipe is surrounded by dead air. Then cover that enclosure snugly with say a one-foot thickness of foil-backed fiberglass insulation. Then pile a mound of straw or hay on it and cover it with a plastic sheet. If beforehand you stick the probe of a digital indoor/outdoor thermometer on the end of the water pipe, maybe you can read the temperature inside to see that it's staying way above the outside temperature.

I don't guarantee it, but it makes sense to me.

Edit: I shouldn't say that the air would be dead. It would be circulating by convection inside the PVC pipe---colder at the top, warmer at the bottom. The point is that it shouldn't exchange with air outside the PVC pipe.

Edit: replaced "iron pipe" with "water pipe".

 

[Jadnashua]

The problem is, he wants to keep other things on that line functioning. Even if you capped that line after draining, the trapped air would eventually get absorbed by the water in the line. How fast, that's hard to say. The only reliable way to ensure things don't freeze is to keep the line dry, or add some heat.

 

[LikeABigFriedEgg]

The problem is, he wants to keep other things on that line functioning. Even if you capped that line after draining, the trapped air would eventually get absorbed by the water in the line. How fast, that's hard to say. The only reliable way to ensure things don't freeze is to keep the line dry, or add some heat.

Not talking about draining the water pipe. There is a 6" PVC pipe surrounding the water pipe. I assume there is air between the two pipes. Need to trap the air in the PVC pipe (what the OP calls the "shaft").

 

[Cacher_Chick]

Forget about all the methods that might work and do what will be a sure fix. If you will be needing the line in the future, install a shutoff below the frost line. Any piping above the frost line needs to be drained or blown out.