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New to heat pumps. Air handler at full throttle with no heat.

Rob94hawk
Rob94hawk Member Posts: 17
in A-C, Heat Pumps & Refrigeration

My new Bosch Heat pump
Outdoor model: BOVB-60HDN1-M20G
Indoor model: BVA-48WN1-M20

So every so often the air handler blows air at full throttle with no heat and the outside compressor isn't running. It will run like this for a few minutes till it throttles down, compressor goes on, and then heat comes out.

Is there a reason for this? Thanks

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 24,853

    Defrost cycle

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • pecmsg
    pecmsg Member Posts: 5,291

    I thought Defrost was low speed?

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,380

    Without looking at the manual, I would think that is not a normal operating procedure. I would call the installing contractor and voice your concerns.

    Edward Young Retired

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

  • bburd
    bburd Member Posts: 1,039

    Wouldn't the compressor be running in reverse in defrost, and the back up heat also on at the same time?

    —
    Bburd
  • Rob94hawk
    Rob94hawk Member Posts: 17
    https://forum.heatinghelp.com/discussion/comment/1824924#Comment_1824924

    Where does the defrost cycle take place?
    In the air handler in the attic or the compressor outside?

  • Matt_67
    Matt_67 Member Posts: 301

    Defrost is the outdoor coil. Are you sure the compressor isn’t running? The compressor could be running without the outdoor fan going in defrost - I don’t know the sequence on that one without checking.

  • Rob94hawk
    Rob94hawk Member Posts: 17
    https://forum.heatinghelp.com/discussion/comment/1824940#Comment_1824940

    If I happen to catch it happening again I'll go outside and check. It's right underneath my window and I didn't hear it running when the air handler was blasting out cold air.

  • Kaos
    Kaos Member Posts: 217

    If the air handler is blasting cold air than definately defrost. Since the outdoor fan will turn off during defrost, it won't make all that much noise. Usual way this is handled on almost all other inverter heat pumps is to shut off the blower during defrost and don't turn it back on till the coil is back up to temp, I'm surprised it is not an option on these.

  • HVACNUT
    HVACNUT Member Posts: 6,331

    The Bosch system will automatically run the fan at high speed whenever the electric resistance heat is energized. Which is either when W is energized as a supplement to the heat pump, or during defrost. If you don't have the electric elements, then you have high speed fan only.

  • worldclasshvac
    worldclasshvac Member Posts: 22

    Your missing the backup heating elements to temper the cold defrost air. Maybe it wasnt wired right and you do have a heat kit. What size breaker is installed for the air handler? Have a pic of the front of it?

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