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  1. #1
    Join Date
    Aug 2010
    Location
    Scottsdale AZ
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    7
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    Tempstar PHD48 4 Ton Packaged Heat pump freezing up

    Came home today at 4:00PM to my heat pump, in cool mode, making an odd sound (The unit was installed in November 2017 new and has performed well). Went to roof, took off panels and found things frozen up. Second time this has happened in last 8 months. I had the unit inspected about a moth back by the installing company. He measured the R410 and took temps at the return and send side. He said everything looked good and sounded good. Today was a little overcast, with Temps at 75 degrees, Humidity 23% and Dew Point 35F (I looked these stats up first thing after coming down off the roof).
    We were running the unit at 58degrees set point at the thermostat. Due to a medical condition. I live in Scottsdale AZ, I have a 1800 sq-ft home build in 1993 with poor insulation and no overhangs to shade side of house or windows. Any thoughts on why I am getting Freeze ups?
    I did ask about having a low ambient kit installed, but the guy wanted big bucks to install.

    Any thoughts as to why it is freezing up?

  2. #2
    Join Date
    Jun 2014
    Location
    Dover, DE
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    A 58* setpoint is unacceptable, much too low. You shouldn’t go any lower than 65-68* setpoint.
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

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  3. #3
    Join Date
    Aug 2010
    Location
    Scottsdale AZ
    Posts
    7
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    Thread Starter
    I understand that this may be outside the parameters of normalcy, but med condition requires it. System has been doing it fine for 2+ years. I have a Fujitsu 1 ton mini split. Problem is it only cools to 64 degrees and won't come on if the temp is below that. I need a unit that can cool low. I guess like a computer room unit.

  4. #4
    Join Date
    Jun 2014
    Location
    Dover, DE
    Posts
    11,849
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    Your well outside of the normal design parameters for comfort cooling.
    I understand that a medical condition requires special conditions but the unit will require modification to operate at that low of a setpoint.
    Your simply asking it to do something it was never designed to do.
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

    Local 486 Instructor & Service Technician

  5. #5
    Join Date
    Jan 2014
    Location
    New England
    Posts
    6,764
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    “I did ask about having a low ambient kit installed, but the guy wanted big bucks to install.”

    What is the lowest outdoor temperature it gets in Scottsdale?

    If your system never iced before with the exact parameters, except for 8 month ( what was the OD temperature at that time and this time ) ago and your recent problems maybe indoor coil is getting dirty, you changed the type of air filter used ( to restrictive) couple supply registers closed. If you have a return air grille type try opening it and remove air filter ( for test purposes ) and run it with the grille open. Did at anytime the Tech. install gauges on your system, if the tech was sloppy with the install and removal of the gauges possibly they removed/vented enough refrigerant to make a difference in the refrigerant charge. Packaged unit typically do not hold a lot of refrigerant charge. As mentioned your beyond the working operation of that system.

    May need a system with a hot gas bypass to put a false load on the indoor coil, if they even make a system like that in a small packaged unit or even if that would work as your maintaining such a low indoor temperature.
    Last edited by Bazooka Joey; 03-25-2020 at 11:07 PM.

  6. #6
    Join Date
    Jan 2010
    Posts
    19,279
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    You need a refrigeraton contractor for that temperature.

  7. #7
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    27,223
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    Below 68* is med temp refrigeration.

  8. #8
    Join Date
    Jan 2004
    Location
    PA
    Posts
    78,519
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    Have them clean the coils. It probably needs very very clean coils not to freeze up trying to get it to 58F.

    I don't see you mentioning needing it to be 58 in your other threads. Even see where you had turned it off at the breaker. So this must be a new condition.

    Never heard of a med condition that required a 58 degree temp. Is it you, or your wife that needs it.

    I feel for either one of you, not being able to leave the house.
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