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Thread: High Suction and Discharge in Heat Mode

  1. #41
    Join Date
    Dec 2004
    Location
    Chicago area
    Posts
    11,739
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    Did you check the charge in cooling mode?

    Based on OA temp, and indoor wet bulb?

    14 degree of superheat may be a bit too low.

    Target Superheat :
    ((Indoor wet bulb x3)-80-oat)/2


    Sent from my iPhone using Tapatalk

  2. #42
    Join Date
    Jan 2021
    Location
    South Texas
    Posts
    34
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    Pictures of the air handler with the cover off show a total of 96 tubes on the ARUF25b and 108 tubes on the ASPT25b. Around 12 percent more.

    At one time it was stated that with an acceptable charge that worked in heating, the cool numbers showed high superheat and high subcooling. Possibly the piston in the air handler is too small. Switching it to a TXV and using the minimum charge would be the only possible solution with the existing coil.

    If the customer is looking for 16 SEER, a new air handler would be required, if not a TXV on the indoor coil would be my next step.

  3. #43
    Join Date
    Nov 2011
    Location
    USA
    Posts
    2,812
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    Quote Originally Posted by 3rdcoast View Post
    If the customer is looking for 16 SEER, a new air handler would be required, if not a TXV on the indoor coil would be my next step.
    Ditto...

    Goodman expanded data for the ASPT31 match shows 153 psi suction at AHRI rating conditions...lots of luck with that.

  4. #44
    Join Date
    Aug 2009
    Location
    Beatrice, NE
    Posts
    14,010
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    Putting a new coil w/TXV would be the best option, adding a TXV with a charge robber would be 2nd, adding a TXV will help but I don't see it compensating for volumetric coil differences.

    When the Trane XL19i first came out I put one it my house and inadvertently put in the wrong size TXV coil. I was able to adjust the charge and get it to work but not like it should have. Later I replaced the coil and achieved much better operation out of it. So in that case the TXV was not enough to compensate for coil volume difference. I think the only thing that saved me at the time was the 19i's were R-22 which seems to be much more forgiving on charging issues.

  5. #45
    Join Date
    Mar 2005
    Location
    5,000 ft
    Posts
    2,380
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    Off the wall question.
    Is the electric BU heat before the coil and possibly energizing when it shouldn't?

  6. Likes heatingman liked this post.
  7. #46
    Join Date
    Nov 2020
    Location
    Denver, Colorado
    Posts
    21
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    When running the unit in cooling, it seems like its overcharged possibly? What was your R/H when the ODT was at 69 degrees, or if you have the Indoor W/B temp, that will work as well.

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