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  1. #1
    Join Date
    Sep 2011
    Location
    I live in a rural area,40 miles east of Memphis,Tn.
    Posts
    5

    Question cold liquid line at condenser

    Arrived at house to check 18000 btu mini split a/c only that was not cooling. When I turned it on at the condenser it very quickly started frosting up on the liquid line at the valve and upward. The air off the condenser was warm.The low side was 35.{R-22} I didn't know what to do, so I removed the freon and vacuumed and recharged 4#8oz. When I restarted the unit, the liquid line felt as cold as the suction.My pressure was 55 low side and 75 high side.The line didn't frost while I was there. The ambient was 82 and the inside air from the inside unit was 60. I'm thinking bad compresser,but why is the liquid line so cold?

  2. #2
    A lot off mini splits meter the refrigerant at the condenser so the liquid line is more of a saturated line. Was the liquid line insulated?

  3. #3
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,338
    The small line that you think is a liquid line, is really another suction line.

  4. #4
    Join Date
    Nov 2011
    Location
    Phoenix,AZ
    Posts
    323
    Quote Originally Posted by ammoniadog View Post
    The small line that you think is a liquid line, is really another suction line.
    its actually the saturated refrigerant line

    did you find the leak?

  5. #5
    Join Date
    Oct 2010
    Location
    AZ
    Posts
    647
    Not familiar with these, but if he read 55psi and 75 psi, is that just the pressure drop from start of suction line to compressor inlet that he is reading? i.e. the pressure drop across coil and piping is 20 psi?

  6. #6
    Join Date
    Nov 2011
    Location
    Phoenix,AZ
    Posts
    323
    They usually only have 1 gauge port

    You can only charge by weight

  7. #7
    Join Date
    Sep 2011
    Location
    I live in a rural area,40 miles east of Memphis,Tn.
    Posts
    5
    Can someone refer me to a source for more complete info on this type of system?

  8. #8
    Join Date
    Sep 2011
    Location
    I live in a rural area,40 miles east of Memphis,Tn.
    Posts
    5
    liquid line is not insulated

  9. #9
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,338
    Quote Originally Posted by KevinAdv View Post
    its actually the saturated refrigerant line
    OK, then there is no suction line. The small one is the "saturated" and the bigger one is the "superheated" pipe. Both lines are on the "suction" side of the metering device, though.

    Most mini-splits have either an electronic expansion valve, a piston, or a normal txv located in the condensing unit. The metered refrigerant gets sent through this "saturated" line, then to the evap, and then back to the compressor. Not all mini-splits work like this, but most of them do. The ones that do work like this should have both pipes insulated.

  10. #10
    Join Date
    Sep 2011
    Location
    I live in a rural area,40 miles east of Memphis,Tn.
    Posts
    5
    Is there a way to tell ,by looking at the outdoor unit, if it meters at the condenser or the indoor unit? I'm interested in the possibility of interchanging different brands of units.

  11. #11
    Join Date
    Jun 2014
    Location
    Louisiana
    Posts
    5
    What brand? As stated above, most of these units meter the refrigerant at the condensing unit. There for the "liquid" or small line should be cold but not frosting. Most likely a leak at the flare fittings.

  12. #12
    Join Date
    Sep 2011
    Location
    I live in a rural area,40 miles east of Memphis,Tn.
    Posts
    5

    what brand

    Quote Originally Posted by BBalfe View Post
    What brand? As stated above, most of these units meter the refrigerant at the condensing unit. There for the "liquid" or small line should be cold but not frosting. Most likely a leak at the flare fittings.
    I'm w anting to know how to tell if a unit meters at the condenser or at the evaporator .I don't want to check in here for every brand I encounter. Thanks Jim

  13. #13
    Join Date
    Sep 2007
    Location
    edmonds wa
    Posts
    251
    you can get about all the info for any brand using google.

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