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  1. #1
    Join Date
    Sep 2008
    Location
    Western PA
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    25,433

    Subcooler testing?

    It might seem pretty simple to test a subcooler, but leave it to me.

    Was looking at one yesterday and trying to test or prove performance. Mostly for my own satisfaction, but also am looking to make this a part of annual testing.

    Inlet liquid temp was 66 degrees.

    Running full subcooling which was a 5 ton valve, I think, at a 40 degree evaporator temp. I measured 2-5 degrees superheat on the subcooler.

    Outlet temp was 67 degrees?

    Something doesn't add up here. What am I missing?

  2. #2
    Join Date
    Feb 2008
    Location
    California
    Posts
    2,064
    these reading do not make sense

    First checks are to make sure your subcooling circuit has a solid column of liquid feeding the TEV.

    Then make sure your liquid to be subcooled is a solid column.

    key point here being (you cannot subcool vapor)

    Then your subcooling circuit should have around 10 to 12* superheat (40*SST with a 50* sensible suction pipe temperature)

    Your liquid to be subcooled is entering at 66* and should be leaving towards the liquid header at around 50 to 55* sensible pipe temperature.


    The readings you provide give me the impression that your subcoolers TEV is leaking through the push rods and into the externally equalized line. Giving you a low superheat reading, with no active heat transfer on your liquid to be subcooled.

  3. #3
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,433
    Quote Originally Posted by Phase Loss View Post
    these reading do not make sense

    First checks are to make sure your subcooling circuit has a solid column of liquid feeding the TEV.

    Then make sure your liquid to be subcooled is a solid column.

    key point here being (you cannot subcool vapor)

    Then your subcooling circuit should have around 10 to 12* superheat (40*SST with a 50* sensible suction pipe temperature)

    Your liquid to be subcooled is entering at 66* and should be leaving towards the liquid header at around 50 to 55* sensible pipe temperature.


    The readings you provide give me the impression that your subcoolers TEV is leaking through the push rods and into the externally equalized line. Giving you a low superheat reading, with no active heat transfer on your liquid to be subcooled.
    Didn't make any sense to me, either, that is why I brought it here.

    Solid column of liquid for both.

    Didn't think about that happening with the TXV.

  4. #4
    Join Date
    Feb 2008
    Location
    California
    Posts
    2,064
    Seen it happen a few times.

    If you change the TEV, consider Sporlans Y1155. it is designed for subcooler operation.

  5. #5
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,433
    I knew there was a subcooler TEV out there.

    It is a wide range valve, right? That would require repiping to do away with the dual valve arrangement. Might not be a bad thing.

  6. #6
    Join Date
    Apr 2002
    Location
    Dallas, TX
    Posts
    2,987
    Quote Originally Posted by jpsmith1cm View Post
    I knew there was a subcooler TEV out there.
    Who else would make a specialized supermarket flow control valve.
    If the only tool you have is a hammer, you tend to see every problem as a nail. – Abraham Maslow

  7. #7
    Join Date
    Mar 2008
    Posts
    257
    Sounds like you need to set the valve. Why would you remove the duel valve set up? the Y series works well in this application.
    http://www.parker.com/literature/Spo...10/10-10-4.pdf

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