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  1. #1
    Join Date
    Aug 2019
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    Line set for new AC

    My old AC was 20 years old and it was replaced by a new Lennox last month. The installer replaced only the suction line (the larger one) but not the liquid line.

    I complained to the store because both lines was supposed to be replaced. Now they offer to replace the liquid line for me.

    Since my new AC has been running for a whole month, is it too late to change out the liquid line?

  2. #2
    Join Date
    Dec 2006
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    Vancouver, B.C.
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    Why did you replace your last unit? Was it a due to a compressor burnout, other failure, or simply to avoid the inconvenience of it failing at an inconvenient time?

    Ideally it should have been changed but if they cleaned it out well enough before reconnecting it to the system then it shouldn’t have done much harm if any at all.

    Are they replacing the filter dryer as well when they replace the liquid line?


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  3. #3
    Join Date
    Mar 2015
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    Hamersville, Ohio
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    Why did they only replace the suction line?

    If it were a leak, in the suction line, that could've been repaired.

    If the insulation, on the suction line had fallen off, that could've been replaced.
    Hos 4:6 My people are destroyed for lack of knowledge. Because you have rejected knowledge, I will also reject you, that you may be no priest to me. Because you have forgotten your God’s law, I will also forget your children.


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  4. #4
    Join Date
    Aug 2019
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    Thread Starter
    The new AC is Lennox 2-tone unit, EL16XC1-024.

    According to the product specs, the suction line is 3/4 and the liquid line is 3/8.

    It replaced an old York 1.5 tone unit which came with the house maybe 20 years ago. While the old unit still worked, it ran for the whole day and did not cool the house well. I did have to add more fluid (Freon?) 2 years ago.

    The salesman told me that the installer would replace both lines because of the sizes of the lines had changed over the years. I recall he told me that the old liquid line was either 1/4 or 5/16. Also, I read that the old and new units use different refrigerants and they produce different oil residual which should not mix.

    For the installation, I know the installer only changed out the suction line but not liquid line. I do not know if he flushed out the old liquid line or did a pressure test.

    My question is since the new AC has been running for a month, I am wonder if it still makes a difference to change out the liquid line? I hope this AC would last me 10 years.

  5. #5
    Join Date
    Aug 2002
    Location
    Southold, NY
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    There’s no issues with mixing of the oil, Not enough to worry about. As far as liquid line size “I” don’t see an issue but I would have the contractor call tech support and ask them!

  6. #6
    Join Date
    Jan 2010
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    How long are the lines and what size is the new one ?

  7. #7
    Join Date
    Aug 2019
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    Thread Starter
    Quote Originally Posted by VTP99 View Post
    How long are the lines and what size is the new one ?
    According to the product specs, the suction line is 3/4 and the liquid line is 3/8.
    The lines are maybe 30-35 feet long.

    BTW. At the same time, they changed out the furnace by a Lennox 66K BTU, EL296UH070XV36B.

  8. #8
    Join Date
    Jan 2010
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    Did they add any refrigerant to the new system ?

  9. #9
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    Aug 2019
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    Thread Starter
    Quote Originally Posted by VTP99 View Post
    Did they add any refrigerant to the new system ?
    It is a brand new AC. They would not ship the AC with refrigerant, right? I would think they added the refrigerant after the installation.

  10. #10
    Join Date
    Jan 2010
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    Quote Originally Posted by Mis3 View Post
    It is a brand new AC. They would not ship the AC with refrigerant, right? I would think they added the refrigerant after the installation.
    So apparently you were not there to see the installation.
    The outdoor unit comes precharged with the refrigerant.
    Typically that change is for lines up to 15'. Additional refrigerant must be added to compassionate for any longer line length.

  11. #11
    Join Date
    Aug 2019
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    Thread Starter
    Quote Originally Posted by VTP99 View Post
    So apparently you were not there to see the installation.
    The outdoor unit comes precharged with the refrigerant.
    Typically that change is for lines up to 15'. Additional refrigerant must be added to compassionate for any longer line length.
    I was actually home for the installation. He did ask for my permission to break the drywall to change out the lines. While my basement is finished with drop ceilings, he still had to break 4 holes in the drywall.

    I worked from home that day so I did not watch the whole 12- hour installation. To think of it, they showed me the new refrigerate so they did add.

  12. #12
    Join Date
    Oct 2014
    Location
    Columbus, Ohio
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    If the old line is 1/4" and the new unit calls for 3/8", it will still work, but at the cost of some capacity and increased electricity usage (1-3% perhaps). It will also change the calculation used for figuring out the additional refrigerant charge, so if they just went off the default specs for 3/8" line, it would be overcharged by a small amount, further reducing efficiency.

    TL;DR, it will work, but at a small loss in performance.

  13. #13
    Join Date
    Aug 2019
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    Thread Starter
    Quote Originally Posted by rjk_cmh View Post
    If the old line is 1/4" and the new unit calls for 3/8", it will still work, but at the cost of some capacity and increased electricity usage (1-3% perhaps). It will also change the calculation used for figuring out the additional refrigerant charge, so if they just went off the default specs for 3/8" line, it would be overcharged by a small amount, further reducing efficiency.
    TL;DR, it will work, but at a small loss in performance.
    Good point. Worse is the lineset are 35 feet long. The old line is smaller so it may further reduce the efficiency, right?

    Let say if the installer did not flush out the old R22, what possible adverse impacts are there to the new AC?

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