How do I insulate buried 3/4" PVC?

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Old 11-27-16, 09:09 AM
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How do I insulate buried 3/4" PVC?

I've tapped into my copper main water supply line with a brass Tee and run 10 feet of Schedule 40 PVC to my sprinkler controls, with a PVC shutoff valve before the control. The PVC is about 8" deep.

Hard Freezes are rare here in warm, dry West Texas. The galvanized steel pipe that the PVC replaced never froze in 30 years of service. I haven't covered the new pipes up yet and was wondering if it's worth adding some kind of insulation.

Do they make any pipe wraps that will work for buried PVC?
 
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Old 11-27-16, 09:17 AM
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The earth itself is the insulator.

If you didn't have a steel pipe break..... you won't have a PVC break.
 
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Old 11-27-16, 09:18 AM
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Doesn't sound like you will need it, but one approach would be to cover the pipe with dirt, just flush to the top of the pipe. Lightly tamp it and place a 6" or so wide piece of rigid flat on top. The warmth from below and the protection from above should be all you need. Obviously the wider the better but I suggested 6" as an example.

Bud
 
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Old 11-27-16, 09:52 AM
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I'm guessing Bud meant to say rigid flat foam.
 
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Old 11-27-16, 10:05 AM
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Here in east tenn we see the occasional zero temps. My 3/4" PVC supply line runs up the mountain and in spots is buried only 5-6" because of slate rock. I've never had any of the water line freeze unless for some reason it become unburied.
 
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Old 11-27-16, 01:35 PM
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Yes rigid foam board, thanks Pete.

Bud
 
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Old 11-27-16, 01:45 PM
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...with a PVC shutoff valve before the control.
Probably a bad move as the PVC valves have a tendency to get stuck and then never move. IF you want to use a PVC valve then the only style I recommend is a "true union" valve that can be easily replaced when it fails. Problem is, they are rather expensive.
 
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Old 11-27-16, 04:39 PM
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And make sure you have a backflow preventer between water main and irrigation system. If you lose water pressure in the main, you don't want water from the irrigation system contaminating your drinking water.
 
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Old 11-28-16, 09:22 PM
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"And make sure you have a backflow preventer between water main and irrigation system."


I'm using 3/4" brass anti-siphon valves for the sprinkler controls. Hopefully they work as advertised.
 
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Old 11-28-16, 09:29 PM
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"the PVC valves have a tendency to get stuck and then never move."

I'd planned to use the heavy 3/4" PVC ball valve made by American Valve. Are you saying those tend to stick????

It's main purpose would be to shut the water off to the sprinkler system in the Fall and open it back up in the Spring, so it would only be operated twice a year.

I had a brass gate valve which worked fine even after 30 years with the galvanized steel pipe. I thought the PVC ball valve would be even more reliable. Wrong assumption?
 
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Old 11-29-16, 03:12 AM
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I know some of the members have had bad luck with the PVC ball valves but I have several on my property and they've always worked fine for me. The one that shuts off my exterior spigots is 20-25 yrs old, probably gets used a dozen or so times each winter. The others get used maybe once a year.
 
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Old 11-29-16, 03:44 AM
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The less often a valve is "exercised" the more likely is it to jam in place. Higher quality valves (more expensive) are less likely to jam than are less expensive valves.

If the valve is one piece with socket solvent welded ends I would NOT use it. Spend the extra dollars for the true union valve and at least you will be able to replace it easily if it fails. Use a larger "vault" rather than just a hand-hole for future maintenance.
 
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Old 11-29-16, 04:07 AM
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I would adapt a brass ball valve to the system. Definitely not a PVC valve. As the others say, the valves tend to stick and not shut off properly over time.
 
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