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Thread: Is it REALLY recommended to run both bare copper lines inside one insulation sleeve ?

  1. #1
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    Is it REALLY recommended to run both bare copper lines inside one insulation sleeve ?

    The HVAC people here all want to run both bare copper lines for a mini split touching each other inside one insulation sleeve. This doesn't make sense to me and they can't explain their insistence. I would think one would want the hot line outside the insulation in free air to dissipate the heat before it even gets back to the compressor. But then I see line sets for sale with both separately insulated.

    Insulating the cold line is obvious. What's not obvious is allowing the hot line to reduce the efficiency of the cold line before it hits the interior unit.

    Can someone provide the logic for what should actually be done?

    Does it make a difference if the unit is only going to be used for A/C in a climate that's always above 70 degrees?

  2. #2
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    The install manual say insulate separately!

    there being cheep, the insulation costs more then the copper!

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  4. #3
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    The original insulation the installer put on turned to some slimy mess after about 18 months. I purchased 1/1-2" wall Armaflex and they still insisted on putting both copper lines inside one sleeve. I can't understand why As I've got lots of the Armaflex left over.

    In a pure A/C scenario - no heat pump to produce heat - what is the point of insulating the return hot line since the compressor unit then spends energy to get rid of the heat via the fan? If that line were in clear air for the 15' run, heat would be lost to the atmosphere in a warehouse situation where the entire warehouse is otherwise not climate controlled with huge garage doors open to the atmosphere.

  5. #4
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    Because the manufacture wants it that way!

    the metering device in in the outdoor unit, both lines are suction line.

    and

    Because the manufacture wants it insulated seperatly!

  6. #5
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    separate...And both insulated

  7. #6
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    Both pipes are vapor BUT there is a temperature difference. Each line should be separately insulated. If this contractor cannot understand it, get a better contractor who will follow the installation instructions.
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  9. #7
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    kdean1: You might find knowledgeable contractors in Athens, Ohio, but not on Roatan Island. That's why I ask here for the technical reasons for insulating the hot line. I do that as an engineer to understand what's going on since the local A/C people haven't a clue.

  10. #8
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    Quote Originally Posted by RoatanBill View Post
    kdean1: You might find knowledgeable contractors in Athens, Ohio, but not on Roatan Island. That's why I ask here for the technical reasons for insulating the hot line. I do that as an engineer to understand what's going on since the local A/C people haven't a clue.
    They may not have a clue but can they read a manual? All they need to do is follow the installation instructions laid out by the manufacturer and not try and fly by the seat of their pants.

    I am guessing you may need to check up on them like a grade school teacher.

    Sent from my SM-G965W using Tapatalk

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  12. #9
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    Both lines are the same temperature, relatively speaking, all the time.

    Is there harm in insulating them together?
    Couldn't tell you. Someone much smarter than me says separate and insulate.

  13. #10
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    That would be incorrect and counterproductive. Which is why the manufacturer specifies that both lines be separately insulated.

    Just to clarify - there are no 'bare copper lines' with a mini-split installation.

    To further clarify - there is no "hot line" on a mini-split cooling-only application - Both lines are effectively a portion of the cooling coil.

    The reason for the the lines' insulation is to reduce the heat gain from the surrounding ambient air into the refrigerant line.

    PHM
    --------


    Quote Originally Posted by RoatanBill View Post
    The HVAC people here all want to run both bare copper lines for a mini split touching each other inside one insulation sleeve. This doesn't make sense to me and they can't explain their insistence. I would think one would want the hot line outside the insulation in free air to dissipate the heat before it even gets back to the compressor. But then I see line sets for sale with both separately insulated.

    Insulating the cold line is obvious. What's not obvious is allowing the hot line to reduce the efficiency of the cold line before it hits the interior unit.

    Can someone provide the logic for what should actually be done?

    Does it make a difference if the unit is only going to be used for A/C in a climate that's always above 70 degrees?
    PHM
    --------
    The conventional view serves to protect us from the painful job of Thinking

  14. #11
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    there is no "hot line" on a mini-split cooling-only application

    Shows you what I know.

    Thank You.

  15. #12
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    If all else fails read instructions 👌🏻

  16. #13
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    No worries - I have no idea how to raise tropical fish. <g>

    PHM
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    Quote Originally Posted by RoatanBill View Post
    there is no "hot line" on a mini-split cooling-only application

    Shows you what I know.

    Thank You.
    PHM
    --------
    The conventional view serves to protect us from the painful job of Thinking

  17. #14
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    The only problem I can see with having them shoved into the same insulation would be the possibility that they might rub together and create leaks over time.

    On the few mini-splits that I've done, I'm pretty sure they came out of the head unit wrapped together in the same insulation. I believe the main reason that the pipes need to be insulated is to prevent mold and water damage to places that the lineset travels through.

    If the installers didn't use a mini-split lineset that came pre-insulated, they might be having a hard time finding pipe insulation small enough for the smaller of the 2 "suction pipes". The small line does need to be insulated though. In this case, I might be tempted to shove both pipes into the same insulation also. Perhaps if they taped both pipes tight together every few feet with electrical tape it might lessen the chance of them rubbing holes in each other. Or perhaps that would make it worse. I'm not sure. Nevermind.
    If at First You Don't Succeed, Skydiving Is Not for You.

  18. #15
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    Coming out of the head is a Non issue. 10, 20, 50 ft of line set the temperature sensors get screwed up readings and everything runs off temperature readings!

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