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  • Need heat pump advice, please

    I have a 2 yr old Bryant heating system. When it got down to approx 25 degrees the heat pump cooling fins completely frosted over, inside and out. Even stayed that way when it was 42 degrees out. Heating seems to be working OK but is this normal? Had the HVAC guy out here to check in the first winter and he said the defrost setting was set to 90 mins instead of 30. He changed it to 30. The 3/4" copper pipe that runs from the heat pump to the furnace is hot to the touch so I guess it's bringing heat into the furnace. I confused. What's going on with this unit and should I call the service guy again?

    Any help would be much appreciated.

  • #2
    Re: Need heat pump advice, please

    Darn near impossible to help you without some pretty detiled information.

    Ice on the condenser coil is a normal heat pump condition and will even happen when the ambient temperature is above freezing. The ice should build up and the unit should go into a defrost...

    When it does this the fan on the outdoor unit should stop spinning and you should hear a *wooooosh* noise as the reversing valve changes over. It is also common for people to say "my outdoor unit is smoking or steaming" while the system is in defrost.

    The ability of your unit to defrost (get rid of it's ice build-up) can also depend on the ambient temperature.

    Your system should be able to terminate it's defrost cycle on teperature as well as time. If the unit is not defrosting on temperature the sensor could be bad or it could have lost contact with the coil and the unit is simply defrosting on time since your default is only set to 30 minutes it may not be enough based on your ambient temperatures.

    In a nut shell, ice is normal but should go away and then immediately start building back up. If the unit is functioning properly, keeping the house at temperature in heat pump mode and you do not see an EMG Heat notification on your stat I would say wait things out.

    Not all HVAC techs are good with Heatpumps. Heatpumps are their own artform

    Bill

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    • #3
      Re: Need heat pump advice, please

      Thanks for the reply. The pump does go into defrost mode but doesn't even melt the heavy frost. The frost is even covering the tubing inside the pump area and a valve on the outside of the pump enclosure. Humidity is around 90-95% here too (north Idaho), if that makes a difference. Sometimes the Aux heat comes on but never the emerg heat. At what temp does the unit stop getting heat from the pump and start relying on the aux heat?

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      • #4
        Re: Need heat pump advice, please

        Most heat pumps lose effectiveness below 32 degrees F and become worthless below about 25 degress F. Heat pumps are great for places that see winter temps in the 30's-40's.

        The heatpump will go into aux heat (electric strips) during defrost. Some systems have the ability to see the ambient temperature and shut off the heatpump and go to straight Aux heating when the outdoor temperature is low enough... It does not asound like your system does this.

        I can't believe a heatpump would be worth having in a cold place like Idaho

        I have seen heatpumps over time develop a shell of ice that will not clear (the coil under the ice does clear but the unit kinda makes an igloo around itself). You could try to help a defrost cycle along by spraying the unit with a garden hose (temperature permiting) to help melt the ice.

        Bill

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        • #5
          Re: Need heat pump advice, please

          Originally posted by marchboom View Post
          I have a 2 yr old Bryant heating system. When it got down to approx 25 degrees the heat pump cooling fins completely frosted over, inside and out. Even stayed that way when it was 42 degrees out. Heating seems to be working OK but is this normal? Had the HVAC guy out here to check in the first winter and he said the defrost setting was set to 90 mins instead of 30. He changed it to 30. The 3/4" copper pipe that runs from the heat pump to the furnace is hot to the touch so I guess it's bringing heat into the furnace. I confused. What's going on with this unit and should I call the service guy again?

          Any help would be much appreciated.
          Is the larger diameter pipe hot to the touch in defrost? It shouldn't be.

          If you can be sure your reversing valve is energized in defrost, but the larger diameter pipe is still hot. You have a problem with the reversing valve.

          It normal to set the call for defrost time at shorter run time intervals in humid climates.

          James

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          • #6
            Re: Need heat pump advice, please

            It goes into defrost (pump fan off and aux heat on) for only about 5-7 minutes and the 3/4" tubing (from the heat pump) going into the furnace is 130 degrees (read approx 6" from pipe with IR thermometer). I don't know how it could get any heat from the outside with all the frost on it. Outside temp now is 32.

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            • #7
              Re: Need heat pump advice, please

              Originally posted by marchboom View Post
              It goes into defrost (pump fan off and aux heat on) for only about 5-7 minutes and the 3/4" tubing (from the heat pump) going into the furnace is 130 degrees (read approx 6" from pipe with IR thermometer). I don't know how it could get any heat from the outside with all the frost on it. Outside temp now is 32.
              When the heat pump goes into defrost, the large diameter pipe should be cool.

              Sure sounds like the reversing valve isn't working properly.

              James

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