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  1. #1

    Heat pump blows cold in heat mode, runs all the time

    Help...we had two heat pumps both 25 years old. They both were still running well with hardly any problems in the 25 years. We decided to replace the upstairs with a new 16 seer unit last summer. We are having trouble with the new unit. It blows warm, then starts blowing cold and then won't shut off. Our contractor thinks we are crazy and says it is doing fine. Our power bill doubled and it is always cooler upstairs. We know it has been unusually cold. Our old unit is running like a champ and keeping us comfortable. What is going on with this new system? Thanks for any suggestions.

  2. #2
    Join Date
    Jul 2008
    Posts
    551
    Does it go through defrost cycles?

  3. #3
    Join Date
    Oct 2008
    Location
    OFFICES IN : ARIZONA - NEVADA - TEXAS
    Posts
    258
    Sometimes the older equipment had a deferent defrost temp and would go into defrost less time ... BBBUT if your bill has doubled " Houston we have a problem " ! - Probably air duct leakage or refrigerant leak / charge , it might be in your best interest to make sure that your defrost frequency is set at 90 min... Demand the dude to fix it or get a second contractor to look at the work ---!
    "Rock-n-Roll " Ain't noise pollution..

  4. #4
    Join Date
    Apr 2008
    Location
    Pa.
    Posts
    1,145
    maybe running in ac mode and backup? what does the air feel like blowing off the outdoor unit?

  5. #5
    I have a 16 seer Rheem HP. My HP was doing the same thing. It ran fine (or so I thought) in A\C mode but when heating, it would heat for a few minutes and then the air coming out would start to cool. My HP was kicking out due to high pressure protection. Check and see if your outside unit is running after the heat goes out. I had to call a serviceman to tell me what the problem was, in my case my Bypass damper was stuck open.
    Last edited by just_w0nd3rin; 02-08-2010 at 11:31 PM. Reason: replaced valve with damper

  6. #6
    Join Date
    Oct 2008
    Location
    OFFICES IN : ARIZONA - NEVADA - TEXAS
    Posts
    258

    Hmm

    Quote Originally Posted by just_w0nd3rin View Post
    I have a 16 seer Rheem HP. My HP was doing the same thing. It ran fine (or so I thought) in A\C mode but when heating, it would heat for a few minutes and then the air coming out would start to cool. My HP was kicking out due to high pressure protection. Check and see if your outside unit is running after the heat goes out. I had to call a serviceman to tell me what the problem was, in my case my Bypass valve was stuck open.
    Maybe my centrifigal cluch is slipin on my king pin too !

    "Rock-n-Roll " Ain't noise pollution..

  7. #7
    Quote Originally Posted by INTECHBILL View Post
    Maybe my centrifigal cluch is slipin on my king pin too !

    Seriously?
    Last edited by just_w0nd3rin; 02-08-2010 at 11:29 PM. Reason: forgot punctuation

  8. #8
    Join Date
    Dec 2006
    Location
    phoenix
    Posts
    120
    Quote Originally Posted by MMax View Post
    Help...we had two heat pumps both 25 years old. They both were still running well with hardly any problems in the 25 years. We decided to replace the upstairs with a new 16 seer unit last summer. We are having trouble with the new unit. It blows warm, then starts blowing cold and then won't shut off. Our contractor thinks we are crazy and says it is doing fine. Our power bill doubled and it is always cooler upstairs. We know it has been unusually cold. Our old unit is running like a champ and keeping us comfortable. What is going on with this new system? Thanks for any suggestions.
    Here's a serious answer to a serious question. Your upstairs area shouldn't be any colder than the downstairs area. However,heat pumps can go into defrost cycles for a few minutes and blow cold air, then go back into heating automatically. If the air is actually blowing cold for more than 10-15 minutes then you may have a problem with the unit. Remember that the supply air may not be very warm during very cold weather. You mentioned that it has been unusually cold there recently.

    Call your contractor and give him specifics and ask him questions. What is the temperature at the thermostat now, 30 minutes later, 60 minutes later, etc. What was the thermostat set at? Does the unit act up all the time or just in the early morning? Does your unit have an outdoor thermostat that shuts down the heat pump and runs electric heat only during cold weather? Electric heat is more expensive than a heat pump (almost always).

    It's unusual to have the upstairs area colder than the downstairs because heat will rise. Good luck talking to your contractor.

  9. #9
    Join Date
    Sep 2009
    Location
    Iowa
    Posts
    139
    Just a question.. on the new heat pump.. is it R410A refrigerant? only reason i ask is because of the installs... they recommend using nitrogen to purge the lines while u braze so u don't get those black floaties.. might be restricting or it could be undercharged? I had one a few weeks ago that came in and i installed it and it was 7lbs under. sorry if i wasn't much help but somethings i look for.

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