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  1. #1
    Join Date
    Jun 2017
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    Freezing room problem



    Greetings,

    I have a cold room at -18 degrees C that does not go bellow -11. Refrigerant R404a.
    At first it had a leak that i fixed but now it does not go bellow -11. It goes to -4 quickly and after that slowly until around -11. Defrost at 4 hours, it doesnt get clogged with ice because there aint much humidity (products are sealed in packages).
    Condenser its not clogged either i cleaned it.
    Evaporator has 2 fans and its kinda too big for the actual room which its around 2.5x2x2.1m
    On the low side it has 2.5bars and the evaporating temperature after condenser its 30-35 degrees C.
    It freezes on return line almost before the compressor and it does not have a liquid separator on the low side.
    Any advice will be of much help.

    Thank you in advance.



  2. #2
    Join Date
    Apr 2008
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    Southampton, England
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    Re: Freezing room problem

    2.5 bar means you are evaporating at -16C, should be more like -30, around 1 bar.
    Was it working before? Air/ non condensables mixed with the refrigerant? TEV been mucked about with?

  3. #3
    Join Date
    Jun 2017
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    Re: Freezing room problem

    True. But at 1 bar not even half of the evaporator is freezing so it doesnt even go under 0 degrees C.
    There is no air or other gasses inside. I vacummed the system to -0.95 bar.
    The owners says it worked before but from my point of view its kinda impossible.
    I also believe that the TEV has been modified or the orrifice its too big, but it makes me wonder how it worked before.
    I believe the next step is to removed the TEV check the nozzle and replace it if its too big right?

  4. #4
    Join Date
    Feb 2009
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    telford
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    Re: Freezing room problem

    You did chsrge it in liquid state i presume

  5. #5
    Join Date
    Apr 2008
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    Southampton, England
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    Re: Freezing room problem

    Perhaps the compressor isn't pumping properly. Might be worth doing a pump down test before looking at the TEV.

  6. #6
    Join Date
    Feb 2009
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    telford
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    Re: Freezing room problem

    Ok can we have some model numbers of evaporator and condensing unit,what is the delivery pressure and temperature going over the condensor please

  7. #7
    Join Date
    Jun 2017
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    Romania
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    Re: Freezing room problem

    Yes i charged liquid.
    I will go there again tomorrow and check compressor model, check high pressure and evaporator model( which i think i wont find since its kinda old).
    Thank you for info for now. I will b
    Return with more info.

  8. #8
    Join Date
    Feb 2009
    Location
    telford
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    Re: Freezing room problem

    In an average ambient,delivery pressure should be around250 psi,do checks on the compressor pump down the liquid to see if it achieves a vacuum,

  9. #9
    Join Date
    Oct 2001
    Location
    Nottingham UK
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    Re: Freezing room problem

    Symptoms of overcharge
    I'm back on the Pale

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