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  1. #1
    Join Date
    Nov 2010
    Posts
    13

    Running Heat Pump during Snow/Freezing Rain

    Is it okay to leave the heat pump run during winter weather or switch over to gas? I read on Portland General Electric's website that the heat pump should be bypassed during an ice storm. I couldn't find mention of anything winter related in the owner's manual. Winter weather for Pullman, Washington is probably 1-2" of snow an hour totaling 6-10" for the storm.

  2. #2
    Join Date
    Oct 2004
    Location
    Central WA
    Posts
    1,314
    Go Cougs! Your heat pump should be set up to switch over to gas automatically at a given outdoor temp. We usually use 40 degrees. This eliminates defrosts and keeps everybody comfortable.

    A heat pump will run fine in cold weather, but it will have to defrost periodically. Defrost is basically air conditioning, but the backup heat comes on so you don't feel it. With gas as your backup heat rather than electric you can't do that. Also in colder weather when the heat pump can't keep up on its own the electric backup will cycle on to assist. Again with gas you can't do that - you have to run one or the other.

    Have a pro come in and verify your controls and settings - make sure its doing what its supposed to do.

  3. #3
    Join Date
    Sep 2002
    Location
    I don't know
    Posts
    2,897
    You should run the heatpump until it is no longer able to maintain the setpoint on it's own or gas becomes more economical - whichever comes first.

    In your case the economic balance point could be anywhere from 20 to 50F OD depending on your electricity rate and gas rate. Every application is different; disregard every rule of thumb brought up on this site.
    General public's attitude towards our energy predicament: "I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"

  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,834
    Heat pups should be shut off during freezing rain. It tends to build up too much ice for defrost to handle.

    Snow and light sleet are not a problem. Have to dig out the heat pump if the snow drifts and buries it.
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  5. #5
    Join Date
    Dec 2002
    Location
    SouthEast NC ICW & Piedmont Foothills
    Posts
    7,623
    let's see, running hp in heavy freezing rain or sleet:

    1- may bend/break the fan blade

    2- may damage motor

    3- that ice accumulation may tear that od coil or piping apart, if od fan continues to run





    BT are heat pups like fun bags
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  6. #6
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,834
    LOL... Not quite.

    I don't like calls for heat pumps when I have to ask them where it is. And they say, "its under that snow somewhere".
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  7. #7
    Join Date
    Feb 2009
    Location
    Tallahassee, FL
    Posts
    5,821
    Quote Originally Posted by beenthere View Post
    LOL... Not quite.

    I don't like calls for heat pumps when I have to ask them where it is. And they say, "its under that snow somewhere".
    Yeah I hate that.

  8. #8
    Join Date
    Nov 2010
    Posts
    13
    Glad I can let it run during snow! Sounds like as long as I clear it along with clearing the driveway after every storm then I should have no issues. So after the freezing rain do I just let the heat pump thaw out (during warmer weather) and then I can run it again?

    Electric is .074/kWh (until 1300kWh) and gas is 0.783/therm. I believe this puts me around 20F economically. It may not heat that low but it's been doing great around 30F and the furnace takes care of the cold bite during defrost. Currently the furnace lockout is at 25F but we haven't got that cold yet.

  9. #9
    Join Date
    Apr 2005
    Location
    NE PA
    Posts
    698
    I would disagree with others concerning ice storms. In over 25 years, I have never seen damage from an ice storm, unless it was so bad that it also significantly damaged other parts of the home as well. The fan is partly protected by the top grill, and the ice will usually shed off the fan when running. Coil damage is unknown. The only issue I have ever seen is very heavy ice accumulating and the unit is not running, resulting is a tough to defrost layer of ice. Rare but it does happen.

    As far as your backup/defrost heat, gas is a fine alternative. The gas can be used during defrost, but generally gas as a backup requires that the HP shut down. There are rare exceptions that can be made to work, but that is not the norm. Most times the HP can run w/o backup into the upper 20's if sized and installed properly.

    paul

  10. #10
    Join Date
    Sep 2010
    Location
    Wa.
    Posts
    119
    The only thing you need to worry about there is the terrible wind! Your Heat Pump should work just fine under proper design conditions!

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