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  1. #1
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    Normal Delta_T For Heat Pump System?

    What is the normally accepted range Delta T between supply & return on the heating side of a heat pump system? My new system was giving about 22F degrees when it was low 50's outside ambient, but barley gives a max delta of 10F when its low 40's outside. Thanks!

  2. #2
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    .

  3. #3
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    switch the fan to auto and system to heat
    Some Talk, Some Do
    "keeping condensing pressures low and evaporator pressures high"
    "Some customers are more interested in comfort than energy savings"
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  4. #4
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    May 2000
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    Indianapolis, IN, USA
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    Sounds very low. Typical 20+ at 30 out, close to 30 degree rise at 50 out with proper airflow.

  5. #5
    Join Date
    Sep 2009
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    Iowa
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    with a bryant h/p and an electric air handler with no heat strips running i was getting a 32 degree F split with a 20 degree F temp. outside

  6. #6
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    McCook NE
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    My Nordyne will give me 20.3 at 17.

  7. #7
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    Quote Originally Posted by BaldLoonie View Post
    Sounds very low. Typical 20+ at 30 out, close to 30 degree rise at 50 out with proper airflow.
    See the key words; Proper Airflow.

  8. #8
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    Dec 2009
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    Seattle, Wa.
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    I had a new Lennox G71MPP furnace and XP14-042 heat pump installed a month or so ago. The Delta T at 55 degrees exterior temperature with the heat pump running was 40.

  9. #9
    Join Date
    Oct 2005
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    Pacific Northwest
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    Quote Originally Posted by BBDartCA View Post
    What is the normally accepted range Delta T between supply & return on the heating side of a heat pump system? My new system was giving about 22F degrees when it was low 50's outside ambient, but barley gives a max delta of 10F when its low 40's outside. Thanks!
    Call 'em back!

    What's you model numbers?

  10. #10
    Join Date
    Jun 2007
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    The Twilight Zone
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    Quote Originally Posted by BBDartCA View Post
    What is the normally accepted range Delta T between supply & return on the heating side of a heat pump system? My new system was giving about 22F degrees when it was low 50's outside ambient, but barley gives a max delta of 10F when its low 40's outside. Thanks!
    Tech Operating Data for my 3-ton, 14 SEER, 9 HSPF pump:

    Ambient-------Temp after indoor coil
    Temp-------(based on 70F return air temp)

    60F---------------105.8F
    50F---------------101.5
    40F---------------97.1
    30F---------------93.4
    20F---------------89.9
    10F---------------86.2
    0F----------------82.6


    Take care.

  11. #11
    Join Date
    Dec 2007
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    4,710
    Quote Originally Posted by gary_g View Post
    Tech Operating Data for my 3-ton, 14 SEER, 9 HSPF pump:

    Ambient-------Temp after indoor coilambient usually refers to outdoor temp unless otherwise specified
    Temp-------(based on 70F return air temp)

    60F---------------105.8F
    50F---------------101.5
    40F---------------97.1
    30F---------------93.4
    20F---------------89.9
    10F---------------86.2
    0F----------------82.6
    if I were to read CAREFULLY you are saying that, for example, an ambient(outdoor) temp of 0*F with a return air temp of 70* gives you a supply temp of 82.6*F or 12.6* temp rise/delta T

    Take care.
    .

  12. #12
    Join Date
    Jun 2007
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    Quote Originally Posted by pacnw View Post
    .
    You are reading the columns incorrectly.

    Ambient temps are in the column going from 60F to 0F, with the corresponding coil temp in the column next to each ambient temp.

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