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  1. #1
    Join Date
    May 2005
    Location
    Obetz, Ohio
    Posts
    2
    Looking for thoughts:
    I'm a service tech and have a new Tempstar 14 SEER HP freezing up after @ 3 hrs. operation. New TXV installed.
    Ambient: 75
    Return DB: 71
    Suction pressure: 55
    Liquid pressure: 160
    Temp drop: 20
    Suction line temp: 40
    Liquid line temp: 80

    Also, unit would no pump refigerant ( R-22 ) back into unit with suction line closed when I installed TXV. Originally had #65 restrictor.
    Can't figure why unit freezes up in cooling mode, except compressor is weak or there's some bypass somewhere.
    Any help would be appreciated. Thanks.

    Mike

  2. #2
    Join Date
    Feb 2004
    Posts
    2,597
    what is a restrictor?

  3. #3
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,317
    Weak compressor valves are usually indicated by suction and discharge pressure beginning to approach one another...IOW the suction will rise to a higher than normal range and the discharge pressure will drop to a lower than normal range. At 55/160 I don't see that as weak valves or compression at all. As for why you couldn't get the system to pump down, perhaps service valves at condenser leaking by? If the installer overheated both of them with his torch, that could be your problem.

    As for the freeze-up, it's possible the check valve in the condenser that bypasses the outdoor TXV or piston is partially restricted or hanging up, causing the liquid line to lack adequate liquid return, which in turn starves the indoor TXV and evap coil. I'd also check your new TXV for any trash in the inlet screen, if it has one.

    Main thing before you heed any of my other suggestions is to CHECK YOUR AIRFLOW!!!

    Being this is a heat pump, did you install a bi-flow liquid line drier? Or a mono-flow with the arrow facing the wrong direction?
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  4. #4
    Join Date
    Feb 2004
    Posts
    2,597
    were you in heat mode when you closed the suction valve?

    was the reversing valve energized or de-energized?

  5. #5
    Join Date
    May 2005
    Location
    Obetz, Ohio
    Posts
    2
    Thanks for the help. Sorry, forgot to mention airflow is fine as is drier. Checked the obvious first. Thanks again, gives me something to work with.

  6. #6
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,880
    You should close the liquid line valve to pump it down.

    160 head sounds low even for a 14 seer.

    Are you you have good air flow.

    Did you check your air flow.

    Might just be alittle under charged.

    Doesn't sound like a compressor problem.

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    How many times must one fix something before it is fixed?

  7. #7
    Join Date
    Feb 2005
    Location
    Dothan, Al
    Posts
    3,453

    obetz

    Suction press low @ 55# with low 40*f suction line temp....

    You have airflow problem - period.



    Hope this helps,
    Richard

  8. #8
    Join Date
    Apr 2004
    Posts
    7,680
    If the airflow is fine, how would you try to explain a flooded coil with low suction pressure? You could try to say the airflow is OK but the coil has been dipped in some insulating paint and heat transfer cant take place but I think unless you are sure thats the case, you better know your airflow. To be fair, if the system airflow is good (within 10% of nominal), you better look for air bypassing the coil.

    Do you have the right coil match?
    What is the actual airflow?
    Is there air bypassing the coil?




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