TXV sizing
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Thread: TXV sizing

  1. #1
    Join Date
    Jul 2004
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    NJ
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    Could you tell me the effects/signs of a wrongly sized expansion valve?

  2. #2
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    Jun 2001
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    San Diego, CA
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    undersized: high subcool, high superheat, low deltaT on evap, localized icing of evap coil likely.

    oversized: low deltaT on evap, low superheat, compressor
    damage likely especially during low load/ high ambient
    conditions.

  3. #3
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    Originally posted by gbfromsd
    undersized: high subcool, high superheat, low deltaT on evap, localized icing of evap coil likely.

    oversized: low deltaT on evap, low superheat, compressor
    damage likely especially during low load/ high ambient
    conditions.
    The only part I can`t comprehend is how can there be low superheat with low delta T on evap.By delta T do you mean air across evap.or air to refrigerant?

  4. #4
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    Sep 2002
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    South Dakota
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    Undersized TEVs starve the evaporator while oversized TEVs hunt and may eventually slug the compressor.


  5. #5
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    Jan 2004
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    Originally posted by altan
    Could you tell me the effects/signs of a wrongly sized expansion valve?

    A lot of spoiled product, and one P.O.ed customer.
    A Diamond is just a piece of coal, that made good under pressure!

  6. #6
    Join Date
    Jun 2001
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    San Diego, CA
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    altan, you're right
    but in an excessively overfed evap - flash gas isn't being
    evenly distributed across the coil. Some flashing occurs in the suction line, hence a low air split deltaT. Not always, only in extreme cases.

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