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  1. #1

    Question Refrigeration line set size

    Is it ok to use 7/8" suction line on a 3/4" indoor and outdoor coil?
    New install lennox 3 ton unit, less than 25' run.
    Had plumber put in gas pipe and line set in exterior wall.The supply house gave him the wrong size and he did not notice the mistake.

  2. #2
    Join Date
    Dec 2003
    Citrus County, Florida
    I'm under the impression that by using a larger size then manuf. recommends, you'll have less velocity and won't get prpoer oil return. I usually run across just the oposite...the lineset is too small resulting is loss of capacity.

  3. #3
    Join Date
    Dec 2003
    I have oversized the suction line many times because I like 7/8 better it is stronger and doesnt like to kink. Never have any troubles. I would say 99% chance, nothing to worry about. If you are still concerned, call the manufacturer and ask for an engineering or applications department, and they will tell you what effects it will have.

    On the new lennox 19 and 21 seer units the require 7/8 on there 2 ton units to get the efficiency levels, and they dont have oil return issues (other than bad installs).

  4. #4
    Join Date
    Jun 2000
    No problemo.
    never say never

  5. #5


    Thanks Guys I knew the answer could be found here !!!!!

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