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Fan speed for heat pump

johntrhodes81
johntrhodes81 Member Posts: 44
in A-C, Heat Pumps & Refrigeration

When a heat pump is in heat mode should the fan cfm be lower than when in cool mode or the same? When I wire it up just wondering what would be best. I can wire it either way just adds a relay.

John

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,484

    If your talking the indoor fan which I am sure you are more cfm would be required on heat do to the heat of compression from the compressor needed to be rejected. On cooling the ahu should move 400-450 cfm/ ton. On heating it would likely be about 520/ton.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,386

    Most of us are in he habit of leaving the fans speed for a heat pump the same for heating and cooling. Not saying that is the best way to do it, just saying what is.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • HVACNUT
    HVACNUT Member Posts: 6,332
    edited July 28

    You adjust fan speed, you adjust the refrigerant pressures.

  • johntrhodes81
    johntrhodes81 Member Posts: 44

    Thanks this is helpful. I increased the indoor airflow and got the house to cool better. I have a txv system and my subcooling went from 12 degrees to 1.5 degrees when the airflow was increased. So had to add some refrigerant to get the subcooling back inline.

    So I definitely won't lower cfm when in heat mode.

    Thank you

    John

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