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Thread: Can extreme bends, too many bends in A/C lines cause noise?

  1. #1
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    Can extreme bends, too many bends in A/C lines cause noise?

    Hi all.

    New to this forum, I appreciate the chance to ask a question.

    I had a new A/C system installed March, right before the pandemic crap hit the fan.

    Since day one, I noticed a pretty loud (to me) noise emanating from the refrigerant lines coming into the house......sound is like a very noisy florescent light in the winter....a buzzing basically.

    Our old system (a 35+ year old 2.5 ton HEIL unit) never made any noise but the installer who did that one used one of those pre-filled line sets and left all sorts of extra line.....so it was all swoopy turns rather than sharp bends....sloppy.

    So when the crew installed this new lineset, they took special care to make it nice and neat.....but in the process ended up putting a ceouple/few 90 degree fittings in the set in order to make corners neater etc.....

    At the outside unit they did a very sharp turn off the unit to go the right direction into the house....then it neds to go in the house...then bends again inside the house to hug the wall, then as it goes into a corner it bends 90 degrees again............THAT is where I hear the racket......right at that last bend.

    The COVID thing has slowed response on everything and this is no different.....the manufacturer eventually told them to try a special line lubricant additive for 48 hours.

    That has made no difference.

    Are the bends the issue here?

    I can post pics and video if that help.

    It is a Bryant 2.5 ton unit, brand new matching a-frame.

    Thanks for any insight from pros and/or folks who have run into this .

    I am trying to add pics but I get the message "this PNG image has the incorrect extension"....my pics are JPGs from my phone....so I am not sure what is going on. And I am unable to add video of the noise til after 7 posts, it says.
    Last edited by shadango; 09-16-2020 at 03:56 PM. Reason: add pics

  2. #2
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    Make sure that line set (both copper pipes) are not touching any portion of the structure. Such as strapped against a 2x4 or against a floor joist, etc. The compressor's discharge pulsation can be heard and felt through sheer contact with the structure of the home itself. Where the piping enters the home they can come through a boot or be silicone to prevent touching the exterior wall, too.

    That is the number one cause of 90% of the noise issues I have run into.

  3. #3
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    Low charge, excess pressure drop, harmonics, improper line support or isolation.

  4. #4
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    Everything sictech said. Also check where discharge line goes under condenser coil inside unit. Make sure it hasn’t dropped and touching base of unit. But if liquid line touches wood you will get noise.

  5. Likes shadango liked this post.
  6. #5
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    Thanks, all, for the fast replies!

    Here are some pics of the install...

    I do not hear or feel noise anywhere in the house EXCEPT at the one section where you see the orange hydraulic press in the picture.

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  7. #6
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    Insulate the liquid line from the metal support, off the brick wall and any where else in contact with building then recheck.

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  9. #7
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    Thread Starter
    I have other pics but am having a hard time deleting the first 6 so I can add more...

  10. #8
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    Quote Originally Posted by ehsx View Post
    Insulate the liquid line from the metal support, off the brick wall and any where else in contact with building then recheck.
    Thanks. So I just went over the 4 or 5 clamps to make sure they are not touching the liquid line.

    In the shot where the orange press is, it was, slightly...was able to move that out a bit so now its not.....

    There was one other that was touching, at the other end , right where it swoops up to go into the drywall, with the orange air hose in the shot (my furnace/A coil is directly on the other side of that drywall) I loosened the metal support so it was not touching.

    I confirmed that the liquid line is not touching anything aside from the foam insulation of the suction line.....

    Still makes the racket.

    The noise and vibration is ONLY present in that 2 foot or so section, right before where that orange press is....no where else at all.

  11. #9
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    Quote Originally Posted by slctech View Post
    Where the piping enters the home they can come through a boot or be silicone to prevent touching the exterior wall, too.
    I wonder if THAT is it...?

    I assumed they had insulation foam on the lines as they came through the exterior wall before they grouted.....maybe not ?

  12. #10
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    SO I am looking at the multitude of pics I took during the install....

    Looks like they DO have insulation on the suction line coming thru the wall before grouting.....

    Not the LIQUID line though.....

    Could the liquid line, since it is making direct contact with the hardened grouting, be the culprit?

    I was assuming that the extreme bends between the outside unit to where the orange press is were the issue.....

  13. #11
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    Quote Originally Posted by ehsx View Post
    Low charge, excess pressure drop,
    When the tech was here the other day he said he checked those and they were OK.

  14. #12
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    Quote Originally Posted by actech2 View Post
    Everything sictech said. Also check where discharge line goes under condenser coil inside unit. Make sure it hasn’t dropped and touching base of unit. But if liquid line touches wood you will get noise.
    Just to be clear, its not a noise that emenantes through the entire floor above or anything....the noise is ONLY in that first section.

    The liquid line IS touching the cinder block wall as it enters the building , vis a vis the hardened grout they used to seal things off.....

  15. #13
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    Here is the noise inside


  16. #14
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    And here is how the outside unit sounds...aside from the fan , you can hear the compressor, but it is no louder than the ANCIENT Heil unit we used to have.......


  17. #15
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    There is a possibility that the lineset was not reamed well right there causing "turbelance" at that section and that's where your noise is coming from. That would mean you need to have it pumped down opened up and copper redone etc.

    Sent from my VS988 using Tapatalk

  18. #16
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    I think Carrier makes a rubber block to put on the line to absorb that noise.
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