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  1. #1
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    Newly made Refrigerating room not reaching temperature



    Greetings everyone,

    I have a newly made refrigerating room which is intended to keep the room temperature between 3 and 5 degrees C.
    I have a compressor unit UNT 6222GK, Evaporating unit ECO EVS181 ED with 3 fans and an expansion valve Danfoss TES2 for R404a.
    The problem is that the room doesnt go bellow 8 degrees C. The room has a triangle shape with dimensions 3/3/2 and a height of 2.5 meters.
    The things is that i really dont know what to do to it or what may be the cause. The evaporating unit with fans off reaches -15 degrees in about 3-5minutes but when the fans turn on, even when the room is around 10 degrees, the evaporator get to +10 degrees C in a matter of seconds. Its like its efficiency is too low. The back pressure its 3 Bars.
    Can it be the expansion valve faulty? or the refrigerating agent bad? Or condensation temperature too low?

    Thanks in advance for any information!



  2. #2
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    Re: Newly made Refrigerating room not reaching temperature

    Hi

    3 bar in R 404 A = -12 C
    Room temp = 8 C
    Delta T = 20
    Open TES to reach suction pressure to 5 Bar
    And then measure super heat and adjust it.
    Also look for short gas .
    Last edited by mbc; 26-06-2017 at 10:25 AM.

  3. #3
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    Re: Newly made Refrigerating room not reaching temperature

    Hi

    What is the Orifice of TES.
    MBC
    Last edited by mbc; 26-06-2017 at 10:27 AM.

  4. #4
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    Re: Newly made Refrigerating room not reaching temperature

    Hi

    The orifice is GR02

  5. #5
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    Re: Newly made Refrigerating room not reaching temperature

    Made a few researches, it might be that i dont have enough refrigerating agent in the system. Im gonna go there today and check high pressure again. Tho i usually charge on low until 2-2.5 bars. Now i have 3-3.2 bars.
    I dont know if the expansion valve will reduce the pressure else the efficiency will turn to nothing.

  6. #6
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    Re: Newly made Refrigerating room not reaching temperature

    It appears that no one understands superheat anymore.
    In all these posts everyone tell you almost everything except what you need including superheat superheat!

    Not sure how mbc can suggest open TES until suction reaches 5 bar, sounds like a lot of guesswork.

  7. #7
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    Re: Newly made Refrigerating room not reaching temperature

    Hi

    I solved it yesterday. The evaporator was smaller compared to what i wordered and i didnt check that out. So the orifice at 0.2 was too big. Changed to 0.1 and it works.

  8. #8
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    Re: Newly made Refrigerating room not reaching temperature

    Hi Ranger
    we had these information
    expansion valve Danfoss TES2 for R404a.
    room doesn't go bellow 8 degrees C
    The back pressure its 3 Bars.

    In 404A 3 Bars = -12 c
    Room temp = +8
    evaporator temp = 2 c =t1
    PS (c) 4.6 bars( -2.1)
    T1 (c) - PS (c) =SH (k)
    2 - (-2.1) = 4.1 = SH


    but he need Room Temp. 3c
    evap temp. -5 c
    -5 -4 SH = -9 (PS) = 3.45 bars .

    I should wrote at 8 c room temp he will have 4.6 bars and in 3 C will have 3.45
    all of them with 6 c delta T

    and also in the end i asked to adjust SH.

    if system is design incorrectly .
    Last edited by mbc; 27-06-2017 at 12:15 PM.

  9. #9
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    Re: Newly made Refrigerating room not reaching temperature

    Quote Originally Posted by mbc View Post
    Hi Ranger
    we had these information
    expansion valve Danfoss TES2 for R404a.
    room doesn't go bellow 8 degrees C
    The back pressure its 3 Bars

    In 404A 3 Bars = -12 c
    Room temp = +8
    evaporator temp = 2 c =t1
    PS (c) 4.6 bars( -2.1)
    T1 (c) - PS (c) =SH (k)
    2 - (-2.1) = 4.1 = SH


    but he need Room Temp. 3c
    evap temp. -5 c
    -5 -4 SH = -9 (PS) = 3.45 bars .

    I should wrote at 8 c room temp he will have 4.6 bars and in 3 C will have 3.45
    all of them with 6 c delta T

    and also in the end i asked to adjust SH.

    if system is design incorrectly .
    Sorry mbc I was incorrect, I saw red as no one seems to know how important it is anymore when troubleshooting.
    You did ask correct questions.

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