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  1. #1
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    Default Freezer Room Behavior

    We had a 2nd hand freezer room installed. 4m x 4m. Running at -10°.

    My question is about the Accumulator (or whatever this is)

    Cold but not frozen.



    All frozen up. Is this normal ?

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    Kobus

  2. #2
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    Default Re: Freezer Room Behavior

    Most possibly overcharged with refrigerant, liquid sludging will destroy that compressor, shout if you need help

  3. #3
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    Default Re: Freezer Room Behavior

    accumulator with ice on it is normal.
    as long as the ice is not forming on the compressor

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  4. #4
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    Default Re: Freezer Room Behavior

    You need to check the superheat and subcooling temps to determine actual performance…
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  5. #5
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    Default Re: Freezer Room Behavior

    Don't know much about it but not maybe a much lower ambient temperature causing ice build-up?

  6. #6
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    Default Re: Freezer Room Behavior

    When I took the frozen picture it was 19°.

    .
    Last edited by KobusDJ; 2024/06/25 at 05:05 AM.
    Kobus

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  8. #7
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    Default Re: Freezer Room Behavior

    That is to much ice on the suction accumulator, meaning the superheat is to low and you are getting some liquid flood back.

    Most likey one of two things are happening here.

    1) The evaporator may be icing up. Either the defrost periods are to far apart or each defrost period is to short on each defrost cycle.
    Start with setting the defrost cycle to four times per day, ie every six hours for 20-30 minutes. Check that the evap coil is frost free after each defrost.
    If the coil is heavily iced up now, it may need a decent defrost for a hour or two. Check that all the defrost elements are working.

    2) The expansion valve may be oversized or the wrong orifice fitted. Check that the expansion valve bulb is tightly strapped down to the suction line where it exits the evap coil. The bulb should be around the 5 or 7 O'Clock position on the suction line.
    If everything checks out ok, you can probably close down the expansion valve by half or a full turn to increase the suction line superheat.

    This is a very basic explanation, but it's probably one of the above.
    Presuming of course that the system was designed correctly to start with, ie, the evap coil matches the compressor capacity, room size, etc.
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  10. #8
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    Default Re: Freezer Room Behavior

    Quote Originally Posted by Searcher View Post
    ............Most likely one of two things are happening here.............
    Thanks for this.

    I will pass it on to the installer.

    They claim it is okay but I doubt it . (The reason for asking.)

    The freezing only started after they changed the controller. The cycle times may be the problem.
    Kobus

  11. #9
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    Wink Re: Freezer Room Behavior

    If the problem started after they changed the controller, then my bet is that the defrost cycles are set up incorrectly.

    A ring of ice an inch or two high around the bottom of the suction accumulator is at times acceptable, but when the whole suction accumulator ices up there's a problem somewhere.

    If the superheat is set to low, it also decreases the efficiency of the system.
    You should be boiling off all the refrigerant in the evaporator coil, not in the suction line and suction accumulator.
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  13. #10
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    Default Re: Freezer Room Behavior

    This is the timer setting.

    Looks like 30 minutes 4 times a day.
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    Kobus

  14. #11
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    Default Re: Freezer Room Behavior

    duplicate
    ..
    Last edited by KobusDJ; 2024/06/25 at 07:46 AM.
    Kobus

  15. #12
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    Default Re: Freezer Room Behavior

    Quote Originally Posted by KobusDJ View Post
    This is the timer setting.

    Looks like 30 minutes 4 times a day.
    That defrost setup looks about right.
    Just remember that the amount and rate of ice build up on the evap coil is dependent on the amount of moisture entering the freezer room.

    So a freezer room with frequent door openings or long loading/unloading periods, needs a more aggressive defrost setup, than say a freezer room that is only opened quickly a few times a day.

    Also when checking the evap coil for ice buildup, don't just look for the white frost at the back of fins. Very often its the hard blue ice deep inside the evap coil that's hard to see, that's the problem. This deep hard ice needs a very long time to defrost.
    It's at times better to switch off the system completely and thouroughly defrost the evap coil and start afresh with a guarateed ice free evaporator.
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  17. #13
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    Default Re: Freezer Room Behavior

    Quote Originally Posted by Searcher View Post
    That defrost setup looks about right.
    Just remember that the amount and rate of ice build up on the evap coil is dependent on the amount of moisture entering the freezer room.

    So a freezer room with frequent door openings or long loading/unloading periods, needs a more aggressive defrost setup, than say a freezer room that is only opened quickly a few times a day.

    Also when checking the evap coil for ice buildup, don't just look for the white frost at the back of fins. Very often its the hard blue ice deep inside the evap coil that's hard to see, that's the problem. This deep hard ice needs a very long time to defrost.
    It's at times better to switch off the system completely and thouroughly defrost the evap coil and start afresh with a guarateed ice free evaporator.
    Let them check if the defrost elements are actually working

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  19. #14
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    Default Re: Freezer Room Behavior

    Quote Originally Posted by Searcher View Post
    That defrost setup looks about right.
    Just remember that the amount and rate of ice build up on the evap coil is dependent on the amount of moisture entering the freezer room.

    So a freezer room with frequent door openings or long loading/unloading periods, needs a more aggressive defrost setup, than say a freezer room that is only opened quickly a few times a day.

    Also when checking the evap coil for ice buildup, don't just look for the white frost at the back of fins. Very often its the hard blue ice deep inside the evap coil that's hard to see, that's the problem. This deep hard ice needs a very long time to defrost.
    It's at times better to switch off the system completely and thouroughly defrost the evap coil and start afresh with a guarateed ice free evaporator.
    That timer must activate the pump down solenoid, stop evaporator fans and supply power to the defrost elements

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  21. #15
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    Default Re: Freezer Room Behavior

    Another thing to bear in mind when defrosting a freezer room is that most evaporator coils have a device called a Klixon attached to the evap coil copper pipe end loops.

    The Klixon is a defrost termination safety device that kicks out the heating elements when the evap coil copper pipe end loops reach around +5 oC.

    So defrost is terminated in two ways, either by the timer ending or by the Klixon reaching temp, whichever comes first.

    This means that setting your defrost timer manually to a few hours may have near zero extra defrost effect, as the Klixon's have usually by then switched off the heaters and no defrost is happening, although the timer is still in active defrost mode.

    The problem with the Klixons terminating the defrost cycle early is that the coil end loops and the outside fins look clear of ice, but it's the hard ice deep inside the evap coil that remains.

    A fast way to clear this hard ice is to switch off the system and hose the evap coil down with tap water until the coil is clear and ice free.
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  22. #16
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    Default Re: Freezer Room Behavior

    And let them make sure the compressor actually stop when going into a pump down
    The LP switch should cut the compressor
    And let them check that the pump down solenoid is also not leaking through causing the compressor to srart up prematurely

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