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  1. #1
    Join Date
    Nov 2007
    Location
    Lincoln, NE
    Posts
    14

    Heat pump: should outdoor unit fan be spinning?

    I just closed on a house built not even four years ago. It has a Ducane system -- an air handler (do not know model just yet) and a HP12B30 heat pump.

    Outdoor temp was 61, indoor temp was 63 and I turned on and set the thermostat to 70.

    While inspecting the rest of the house, I decided to have a look at the heat pump outside. The coils on the outside were about iced over and I could hear the compressor running, but the fan was not moving at all. Just in case I caught it in defrost mode, I checked again five minutes later - no change.

    Granted warm air was blowing out of the vents, but because the system is new to me and I have not figured out all the technicalities yet I cannot rule out the possibility the electric heat strips were on and doing the heating.

    The fan not moving does not sound normal to me, but thought I would run it past you guys first. Service call in order?

  2. #2
    Join Date
    Nov 2006
    Location
    Oregon
    Posts
    853
    Quote Originally Posted by Presence View Post
    Service call in order?
    Yes!!

    The only "normal" scenario for outdoor fan not running and compressor running is defrost but that's highly unlikley at 61 degrees.

    Hire a good tech.

    I'd shut the unit down until then. (pull the disconnect and shut off all the breakers)
    Last edited by beenthere; 11-06-2009 at 10:43 PM. Reason: Removed DIY info

  3. #3
    Join Date
    Jun 2009
    Location
    Kamloops B.C.
    Posts
    31
    By turning the stat so high all at once its very possible that the heat strips came on to supply the heat. With a hybrid system the installers set it so if the stat isnt satisfied (by HEAT PUMP) within 15 mins (preset by installers) it will call for back up heat (heat strips) the heat pump will runn better if you only call for a few degree heat change. Its not designed for turning the stat up and down but a constant temp will be more efficient (read the manuel ) it will explain more
    Last edited by HVAC_James; 11-06-2009 at 11:11 PM.

  4. #4
    Join Date
    Nov 2006
    Location
    Oregon
    Posts
    853
    Sorry beenthere.

    I didn't think that formulating possible root causes of the problem was giving DIY advice. However I now see how it could lead to DIY.

  5. #5
    Join Date
    Nov 2009
    Location
    Kansas City
    Posts
    124
    one quick check would be to <We don't give out that kind of advise either>
    Last edited by beenthere; 11-07-2009 at 04:42 AM. Reason: Removed DIY diagnostic suggestion

  6. #6
    Join Date
    Nov 2006
    Location
    Oregon
    Posts
    853
    Quote Originally Posted by HVAC_James View Post
    its possible that when you turned the hp up that high it couldn't satisfy the stat within the preset time (15 mins usually) and that coused the heat strips to come on. heat pumps are much more efficent when left at one constant temp. not up and down. try leaving the hp set and when adjusting only adjust 1-3 degrees at a time.
    I agree 100% but that would not lead to the outdoor fan not coming on. I think we agree that the system should be checked out.

  7. #7
    Join Date
    Jun 2009
    Location
    Kamloops B.C.
    Posts
    31
    Quote Originally Posted by davefr View Post
    I agree 100% but that would not lead to the outdoor fan not coming on. I think we agree that the system should be checked out.
    If the heat strips come on after 15 mins of load the heat pump would be by passed as if emergency heat was on. Once the stat is satistied its possible the unit will work as designed

  8. #8
    Join Date
    Nov 2007
    Location
    Lincoln, NE
    Posts
    14
    Yes, but keep in mind the compressor outside was still running.

  9. #9
    Join Date
    Nov 2006
    Location
    Oregon
    Posts
    853
    Quote Originally Posted by HVAC_James View Post
    If the heat strips come on after 15 mins of load the pump would be by passed as if emergency heat was on
    Sorry, but I don't see any "normal" scenario where the outdoor fan would be locked out but not the compressor. If the HP get's locked out it's all or nothing based on the contactor.

  10. #10
    Join Date
    Jun 2009
    Location
    Kamloops B.C.
    Posts
    31
    are you 100% it was compressor? i would wait until stat is satisfied then see what happens. If its not working then call for service

  11. #11
    Join Date
    Nov 2009
    Posts
    4
    Quote Originally Posted by davefr View Post
    Sorry, but I don't see any scenario where the outdoor fan would be locked out but not the compressor. If the HP get's locked out it's all or nothing based on the contactor.
    Perhaps the compressor went out on thermal because the contactor welded closed on fire up.

  12. #12
    Join Date
    Nov 2009
    Posts
    4
    there are several reasons the fan would not be running. Call a technician that understands heat pumps.

  13. #13
    Join Date
    Nov 2009
    Posts
    4
    Tried to erase my response... Sorry. I thought the fan was going and no comp.

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