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-   -   Setting outdoor temperature sensor heat pump (https://www.askmehelpdesk.com/showthread.php?t=439956)

  • Jan 27, 2010, 04:11 PM
    bmolch
    Setting outdoor temperature sensor heat pump
    I have a heat pump that is part of a dual fuel system. It shuts off and then a furnace kicks on. Right now the Heat pump shuts off when the tempature falls below 45 degrees. Every thing I've read says the system is capable to down around freezing with no issues. How can I lower the heat pump set point? Where would I find it on the unit itself? I had one of the covers off but there is nothing there indicating a set point. Any help?
  • Jan 27, 2010, 06:05 PM
    hvac1000
    You will need to do a balance point calculation to see exactly when the heat pump is more efficient than the other heating device you are using for the duel fuel setup. This may have been done already by the installer when the equipment was setup when new. It is somewhat foolish to go twisting dials or changing settings when it can end up costing you $$$.
  • Jan 28, 2010, 09:48 AM
    bmolch
    Quote:

    Originally Posted by hvac1000 View Post
    You will need to do a balance point calculation to see exactly when the heat pump is more efficient than the other heating device you are using for the duel fuel setup. This may have been done already by the installer when the equipment was setup when new. It is somewhat foolish to go twisting dials or changing settings when it can end up costing you $$$.

    Actually that's the point I receive a significantly discounted rate on my electric use because of some alternate energy experiments being consucted on "the back forty" so to speeak while I'm paying market price for the propane I burn. Its economics not efficiency the more I can run the electric system (without damaging the unit) the more money I save.
  • Jan 28, 2010, 11:10 AM
    hvac1000
    Just let the heat pump run all the time if the electric is so cheap but common sense says about 15 degrees is all modern heat pumps will still produce heat at without wearing out the unit for no gain. Remember there is heat available in the air at colder temps but the pumps will not be able to take advantage of it in today's world. Someday there will be HP's that will go lower and be available on the market. We have tested units for manufactures that go lower now but they are to expensive and difficult to repair and that is why they are no for sale to the public yet.

    Enjoy the cheap electric while you can.
  • Jan 29, 2010, 07:40 AM
    bmolch
    Quote:

    Originally Posted by hvac1000 View Post
    Just let the heat pump run all the time if the electric is so cheap but common sense says about 15 degrees is all modern heat pumps will still produce heat at without wearing out the unit for no gain. Remember there is heat available in the air at colder temps but the pumps will not be able to take advantage of it in todays world. Someday there will be HP's that will go lower and be available on the market. We have tested units for manufactures that go lower now but they are to expensive and difficult to repair and that is why they are no for sale to the public yet.

    Enjoy the cheap electric while you can.

    That is what I'm trying to do essentially but I can't figgure out how to tell the heat pump not to shut off. I'm guessing there is a setting somewhere that tells the pump to shut off and the propane to come on but cannot find where this setting is physically at
  • Jan 29, 2010, 08:12 AM
    hvac1000
    There are many different ways that the heat pump can be controlled. Depending upon the type of thermostat they have been known to control this especially if they have an outdoor sensor. Then there is the outdoor thermostat that is installed in the heat pump itself. Without being there I have no idea what type of control you have exactly and can not be of much assistance.

    But I would heed one warning and that is you can cost yourself big bucks on a repair or replacement of the unit if you run it to death at lower temperatures with little or no gain. In your situation you would be better off replacing the propane furnace with an electric one since the electric rate is so cheap.

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