Page 1 of 2 12 LastLast
Results 1 to 20 of 26

Thread: "Lightly Buried" Refrigerant Lines in a Dry Climate: How Long Till They Fail?

  1. #1
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,795
    Post Likes

    "Lightly Buried" Refrigerant Lines in a Dry Climate: How Long Till They Fail?

    I realize that's an impossible question to answer. However, if you have an opinion about how long these refrigerant lines will last then please share. My answer to the client was that they will likely last for years, but then there's a big difference between a few years and decades.

    These lines are on and just under the ground for about 20 feet. They've been pushed down in places by concrete that's supporting a deck. We have very low humidity and short rainy seasons. This land appears to be well drained. We believe the lines have been that way for at least 10 years.

    Please note that I did not ask if the lines should be unburied. Of course they should. They should have never been buried to begin with. But now that we're here, cost-benefit is an issue.


  2. #2
    Join Date
    Jan 2004
    Location
    PA
    Posts
    80,300
    Post Likes
    5 to 7 more years, is my guess.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Jan 2014
    Location
    New England
    Posts
    8,779
    Post Likes
    If they are hooked to the original Indoor and outdoor section, the serial number will tell you at least how long it’s been like that. If you have problem figuring that out or would like to know need brand and serial number. Also if the electrical data plate on OD unit is still visible they may even have the built date, even the ID unit may have that, the built date.

    One advantage the larger line has, is it insulated, so that helps. I suppose you can peel away some top soil from the 3/8” liquid line as far in as possible to see if it has fine pitting on the tubing, and compare to the exposed faded copper exposed area. Thinking concrete is not the best thing for copper, especially if it’s encapsulated in concrete.

  4. Likes Zamoramax liked this post.
  5. #4
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,795
    Post Likes
    Thread Starter
    beenthere: I appreciate the directness of your answer.

    BJ: We know the condenser's age, but not how long it's been in its current location. Ten years is an estimate. Originally it was closer to the building. We don't have easy access to the lines because of the deck. I don't believe any of the lines are encapsulated in concrete. I believe they're just under concrete here and there.

  6. #5
    Join Date
    Jan 2014
    Location
    New England
    Posts
    8,779
    Post Likes
    Quote Originally Posted by Irascible View Post

    BJ: We know the condenser's age.
    Dang! I never thought that my profile name shortened to just two letters was that designation, it never accused to me...now I’ll have to change it.....

  7. Likes Zamoramax, beenthere, jacob-k liked this post.
  8. #6
    Join Date
    Jan 2008
    Location
    New Jersey
    Posts
    267
    Post Likes
    In my area copper lines are used for domestic water feed with over fifty years of service. One of the things that shortens the life is not backfilling with clean sand. If any rocks are against the pipe with slight movement it will damage it. Like others said your suction is good, but the question would be on the liquid line.

    Sent from my VS501 using Tapatalk

  9. Likes Zamoramax, VTP99 liked this post.
  10. #7
    Join Date
    Mar 2011
    Location
    New Jersey
    Posts
    49
    Post Likes
    Quote Originally Posted by chander View Post
    In my area copper lines are used for domestic water feed with over fifty years of service. One of the things that shortens the life is not backfilling with clean sand. If any rocks are against the pipe with slight movement it will damage it. Like others said your suction is good, but the question would be on the liquid line.

    Sent from my VS501 using Tapatalk
    I agree... we used copper lines for underground oil tanks and the lines lasted 50 years or more and back then many didnt use protective coatings like they do now... I know its carrying something different but its the same 3/8" copper lines. The only thing that worries me a little more with refrigeration lines is the unit causing vibration in the line set... if there are any rocks that will eventually cause a leak... but if filled with clean sand like you suggested then it shouldn't be an issue. also could have put something around the lineset to protect it. line insulation or something.

    or use something kind of like the orange sleeve that comes on copper for oil lines now

  11. #8
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,795
    Post Likes
    Thread Starter
    Those are interesting comments about the suction line.

    I might have guessed that the sponge-like suction line insulation would be more a detriment than a help because it might keep that line wetter for longer.

  12. Likes Zamoramax liked this post.
  13. #9
    Join Date
    Mar 2011
    Location
    New Jersey
    Posts
    49
    Post Likes
    Quote Originally Posted by Irascible View Post
    Those are interesting comments about the suction line.

    I might have guessed that the sponge-like suction line insulation would be more a detriment than a help because it might keep that line wetter for longer.
    That coating on the oil lines is a high density polyethylene outer sleeve and its really hard to break, even a shovel wont get through it... but that stuff wasnt used until recent years. Ive seen oil lines burried in the ground with no protection and still last decades.

  14. #10
    Join Date
    Jan 2015
    Location
    Iowa
    Posts
    2,002
    Post Likes
    As stated by chander there are many copper water supply lines and can last a life time. Those are usually in a sand bed or good clean dirt. Your picture shows rock / gravel, you mentioned concrete. Neither are real compatible with copper with respect to wearing a hole through it. Especially if the tops side is in a travel path (walking, riding lawn mowers, vehicles) So from what I see in your pictures and what you wrote I would not expect to get the normal service life 15 to 20. If it were me I'd tell the owner start saving their pennies, because when the line fails they will need a whole new installation. As I assume this is an R22 system. (maybe 3 to 5 years but could be tomorrow)

    Good Luck

  15. #11
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,795
    Post Likes
    Thread Starter
    Quote Originally Posted by justin_ View Post
    Ive seen oil lines burried in the ground with no protection and still last decades.
    That's the rub. beenthere and A-M could be right. Or those lines might last for decades more. The customer wants a strong recommendation one way or another, but I don't currently have a strong opinion.

    In a worst-case scenario failed lines will destroy the compressor in the middle of a heat wave. That fear plus the opinions of BT, AM and others will probably lead to a recommendation to replace.

  16. #12
    Join Date
    Jan 2005
    Location
    Emerald Coast
    Posts
    1,187
    Post Likes
    .
    Direct exchange geos are common in certain areas, common in Europe.
    They're copper/soil based. They recommend an anode field but that's beyond this topic. The life of the lines are more dependent on the cleanliness of the install.

    Check out Earthlink if they're still around for geos.
    ..
    Do not attempt vast projects with
    half vast experience and ideas.
    ...

  17. #13
    Join Date
    Jan 2008
    Location
    New Jersey
    Posts
    267
    Post Likes
    Quote Originally Posted by Irascible View Post
    That's the rub. beenthere could be right. Or those lines might last for decades more.

    The customer wants a strong recommendation one way or another, but I don't currently have a strong opinion.

    In a worst-case scenario failed lines will destroy the compressor in the middle of a heat wave. I might just recommend replacing the lines out of fear of that.
    Give them a option, replace or reuse line set. If you reuse lineset, install LP switch to protect compressor in case of refrigerant loss, if condenser doesn't have one factory installed.

    Sent from my VS501 using Tapatalk

  18. #14
    Join Date
    Feb 2016
    Location
    Louisburg Kansas
    Posts
    5,541
    Post Likes
    It is well documented that buried copper pipe will last for many years (50 or more) in soils other than those highly corrosive. In your area the only worry you have is rocks.
    No man can be both ignorant and free.
    Thomas Jefferson

  19. #15
    Join Date
    Apr 2020
    Location
    va
    Posts
    1,528
    Post Likes
    Ashrae has recommendations for buried line protection. I prefer pcv pipe chases.
    Would not worry unless evidence of a leak or new installation, then do it correctly.

  20. #16
    Join Date
    Jan 2004
    Location
    PA
    Posts
    80,300
    Post Likes
    Quote Originally Posted by justin_ View Post
    I agree... we used copper lines for underground oil tanks and the lines lasted 50 years or more and back then many didnt use protective coatings like they do now... I know its carrying something different but its the same 3/8" copper lines. The only thing that worries me a little more with refrigeration lines is the unit causing vibration in the line set... if there are any rocks that will eventually cause a leak... but if filled with clean sand like you suggested then it shouldn't be an issue. also could have put something around the lineset to protect it. line insulation or something.

    or use something kind of like the orange sleeve that comes on copper for oil lines now

    Oil lines have relatively the same pressure in them 24/7/365. Refrigerant lines can have a low pressure for a few hours, and then 2 to 300 PSIG more for 20 minutes. Not to mention the extreme temp change expanding and contracting the lines.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  21. #17
    Join Date
    Mar 2015
    Location
    Medford, N.Y.
    Posts
    7,929
    Post Likes
    The soil/dirt/rocks/pebbles damaging the copper is one part of the equation. Refrigerant Migration is a much more deadly concern. Converting to a Pumpdown and receiver tank and possible discharge line check valve is a compressor friendly way to go.

  22. Likes Irascible, VTP99 liked this post.
  23. #18
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,795
    Post Likes
    Thread Starter
    Thank you everyone for the replies. This forum has been immensely valuable over the years. I don't take the collective effort for granted.

  24. #19
    Join Date
    Mar 2011
    Location
    New Jersey
    Posts
    49
    Post Likes
    Quote Originally Posted by beenthere View Post
    Oil lines have relatively the same pressure in them 24/7/365. Refrigerant lines can have a low pressure for a few hours, and then 2 to 300 PSIG more for 20 minutes. Not to mention the extreme temp change expanding and contracting the lines.
    I completely agree there's a big difference between oil lines and refrigerant lines. to further your point, the oil line would have a vacuum and a fairly constant temperature, with little to no vibration that far from the oil pump. I said I realize they aren't the same but maybe I said it poorly... I was only giving oil lines as an example because I can count on 1 hand how many times I saw buried refrigerant lines around here, yet I see buried oil lines daily (well maybe not *quite* as much now-a-days as underground tanks are going away)

  25. #20
    Join Date
    Feb 2013
    Location
    Sonora, California, United States
    Posts
    5,875
    Post Likes
    Quote Originally Posted by Bazooka Joe View Post
    One advantage the larger line has, is it insulated, so that helps..
    The couple that I have ran into it sure seemed the ground was actually changing the temp of the refrigerant lines. Sub-cool and Super-heat were way off.

    I found another one that ran through PVC and the PVC filled up with water. Again, it was a pita to charge. Its been some years but I'm pretty sure on that one I had to put temp probes in supply and return and charge by temp split...

  26. Likes Bazooka Joe, theoldscroll liked this post.
Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •