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  1. #1

    410 a evap temp quandry

    I have installed a Goodman 16 SEE 410a .

    Could not get the SH and SC in balance so I adjusted the TXV but could not get below a 45* coil.

    I always uses the delta T OF 18* TO 21*.

    tECH SUPPORT SAYS i WAS IN IN THE DARK AGES AND SHOULD BE USING a delaT T on a 16 SEER of 15 to 21.
    But my SH wa not right and the S and I MANUAL SAID TO ADUST SH TO ACHIEVE the evap temp drop.

    Please advise and what is the right method.

    Is it 40 or 45*/
    .

  2. #2
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,325
    Measuring return air wet bulb temperatures will make the difference. Note how wet bulb affects superheat in the chart below when the outdoor dry bulb (ambient) temperature remains the same but the indoor wet bulb temperature varies:

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    Other charts are out there that show how the indoor coil split can vary according to indoor return air wet bulb temperature. If conditions are right, you can see an indoor split as low as 15 degrees and the system is properly charged and working correctly. That would be typically very humid air and a higher than normal return air dry bulb temperature, but nevertheless it is possible.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


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  3. #3
    Join Date
    Jul 2009
    Location
    new york
    Posts
    643
    Whats the copywright on the S and I MANUAL. http://www.energyvanguard.com/blog-b...e-It-s-Correct

  4. #4
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    Quote Originally Posted by itaintme View Post
    I have installed a Goodman 16 SEE 410a .

    Could not get the SH and SC in balance so I adjusted the TXV but could not get below a 45* coil.

    I always uses the delta T OF 18* TO 21*.

    tECH SUPPORT SAYS i WAS IN IN THE DARK AGES AND SHOULD BE USING a delaT T on a 16 SEER of 15 to 21.
    But my SH wa not right and the S and I MANUAL SAID TO ADUST SH TO ACHIEVE the evap temp drop.

    Please advise and what is the right method.

    Is it 40 or 45*/
    .
    As Shophound has eluded to "it is all about air"

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,913
    What is your SC?

    R22-40
    R410A-45
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Quote Originally Posted by beenthere View Post
    What is your SC?

    R22-40
    R410A-45
    Thank you Been there,

    Also thanks to the other responders,

    Yes the low side evap temp will vary with load.

    What i was looking for was a base line that, in the industry,a consensus existed to describe.

    Many thanks.

    oops.. missed the SC (subcooling ?) question: Superposed to be between 5* ans 7*

    with a SH of 7* to*9.

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