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  1. #1
    Join Date
    Nov 2008
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    Northern California, foothills.
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    213

    TRANE Heat Pump metering method.

    Heat Pump Model: 2TWR1030A1000B
    Air-Handler: TWED30C140B0

    Does anybody know the metering devices used for this heat pump?
    Their location would be helpful as well.

    Whilst replacing the evap coil, we found that the old unit had NO
    orifice. The instructions for the new one called for an orifice.
    How could the old one have worked? It was maybe eight years
    old.

    Do they have some kind of bi-flow out at the heat pump?
    Double-metering wouldn't be good.

    Thank you.

  2. #2
    Join Date
    Jul 2009
    Location
    Columbia, MD
    Posts
    4,470
    Outdoor unit has a TXV for heating only. Indoor is a TXV or piston. If you found no metering device inside and just added one you will probably be replacing the compressor soon.

    It's just the nature of the beast. I have found this myself.

  3. #3
    Join Date
    Jul 2007
    Location
    Virginia
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    Quote Originally Posted by georgelass View Post
    Heat Pump Model: 2TWR1030A1000B
    Air-Handler: TWED30C140B0

    Does anybody know the metering devices used for this heat pump?
    Their location would be helpful as well.
    The Air Handler model number should be TWE030C......

    The outdoor unit should have a TXV (inside the cabinet) with a separate check valve. The indoor coil uses a .069 orifice.
    Instead of learning the tricks of the trade, learn the trade.

  4. #4
    Join Date
    Nov 2008
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    Northern California, foothills.
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    I failed to mention that the old compressor did indeed die a horrible burnout.
    But it evidently worked for eight or so years as a heat pump & a/c.
    When pressure-testing the heat pump, we found the strange damage to
    the evap coil and replaced that.
    The fact that the thing worked for eight years leads one to suspect
    that the metering device for the indoor coil was not where it was supposed
    to be. Else a metering device is optional except for the small matter
    of compressor longevity? Strange.

  5. #5
    Join Date
    Nov 2008
    Location
    Northern California, foothills.
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    213
    I replied to the first reply as the second reply was being posted.
    So we have two seasoned ones in agreement that the indoor unit
    needed an orifice. The outdoor unit did indeed have a TXV.
    Thank you. I feel better, I think.
    The replacement compressor appears to not be compressing.
    At least we can be confident that it wasn't related to double-metering.
    What are the odds that a replacement compressor could have such
    an issue?

  6. #6
    Join Date
    Jul 2007
    Location
    Virginia
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    5,919
    Quote Originally Posted by georgelass View Post
    What are the odds that a replacement compressor could have such
    an issue?
    That is always a coin toss.

    I think this outside unit might have come with a filter dryer installed on the liquid line inside the cabinet, before the TXV. Be sure to check that, and replace it, if it is the case.
    Instead of learning the tricks of the trade, learn the trade.

  7. #7
    Join Date
    Nov 2008
    Location
    Northern California, foothills.
    Posts
    213
    Yes, I did the compressor change-out. I had first thought the muffler
    was a filter-drier, until I removed it and read "muffler" on the side. Duh.
    Then I found the real filter drier and replaced it with copper tubing.
    Installed a large bi-flow on the liquid line.

    Thank you for covering the bases.

  8. #8
    Join Date
    Jul 2009
    Location
    Columbia, MD
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    I have had indoor units with no metering device. It is suppose to have one one. Installers just forget to put them in. For some reason it cools somewhat. I forget what my superheat and sub oolong has been.

    This was a burnout? Did you follow burnout procedures? HH driers and replacing them? Maybe reversing valve and check valves have trash in them?

  9. #9
    Join Date
    Nov 2008
    Location
    Northern California, foothills.
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    Quote Originally Posted by gravity View Post
    I have had indoor units with no metering device. It is suppose to have one one. Installers just forget to put them in. For some reason it cools somewhat. I forget what my superheat and sub oolong has been.

    This was a burnout? Did you follow burnout procedures? HH driers and replacing them? Maybe reversing valve and check valves have trash in them?
    New LL drier. No suction line drier. I blew a ton of nitrogen through it.
    Put some acid neutralizer snakeoil in the system. Replaced the evap coil.

    The senior tech doesn't seem to think there is an obstruction.
    We shall see and I'll report back when we do. It might be
    a week or so.

    HH?

    Thanks.

  10. #10
    Join Date
    May 2009
    Location
    Cummins, GA
    Posts
    1,561
    It is unlikely that your new compressor has an issue but anything is possible.

    Report back with some numbers. Such as pressures, delta t, wet bulb, etc. This will help us narrow down the possibilities.

  11. #11
    Join Date
    Nov 2008
    Location
    Northern California, foothills.
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    213
    The senior tech took the reigns and a new compressor is on order.
    But I will report what happens when it does.

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