Buried Refrigerant Lines

[fqp25]

Is this allowed anywhere? I've seen this situation a few times around here.

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[Jim Katen]

Originally posted by fqp25

Is this allowed anywhere? I've seen this situation a few times around here.

I think it's fine. Terry? George?

- Jim Katen, Oregon

[Bill Kibbel]

I've read several Carrier install instructions that state: "Do not bury lineset". I've also seen other brands with R410A that state none to a max of 3' can be buried.

[homnspector]

I see refrigerant lines buried mostly on older homes, I never thought to call it out, some are 40 years old and still apparently not leaking. Usually newer homes ac lines are in the flexible black 4 inch pipe (pvc?), the non-perforated version of foundation drain pipe. Then they shoot a can or two of "great stuff" in the ends.

Is there some limitation to the distance the electrical flex conduit can extend across the ground or in the air?

[Terence McCann]

In the real world I don't think there would be a problem. I'm not sure I'd even mention it. Only problem I see would not being able to leak check the line set should a leak occur but you can always run a new line set [i was going to say "however, you can always run a new line set" but I see that's not acceptable[:-dunce]

[Chad Fabry]

Manufacturers' spec is the deciding factor, but there's nothing particularly wrong with a buried line set.

The new direct exchange heat pumps depend on it.

[Bill Kibbel]

It can be a problem, depending on certain other factors.

Many years ago, I contacted a manu. rep about an installation that had about 15' of buried lineset. (They wanted the outdoor unit behind the pool fence) He explained the issue and why many specs don't allow or at least recommend against it.

If the air handler is in an above grade floor of the home, the lineset is lower than the evaporator and condenser. In the off cycle, with the ground being cooler, the refrigerant can condense into a liquid. When the system kicks on, the liquid can then be pumped into the compressor. Liquid doesn't compress.

He mentioned troubleshooting many systems that had gone through several compressors, before they contacted him to identify the problem.