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  1. #1
    Join Date
    Nov 2009
    Location
    Jakarta
    Posts
    2

    McQuay WSC 087 High Subcool And High Suction SH

    Dear Friends,
    Below is the log readings from McQuay WSC087 microtech II:

    EXV
    95.60
    Con EWT
    82.48
    Con LWT
    92.43
    Con W D T
    9.95
    Eva EWT
    64.96
    Eva LWT
    59.92
    Eva W D T
    5.04
    Eva Ref P
    43.23
    Con Ref P
    123.02
    %RLA
    96.33
    Suction SH is 7F
    Discharge SH is 21F
    CHW Setpoint is 44F
    Evap Saturated Temp 48.00
    Evap Approach Temp 11.92

    Cond Saturated Temp 99.50
    Cond Approach Temp 7.07


    I hv tried to adjust the Suct SH and the discharge SH by closing Liq. Injector and turning the expansion valve screw bolt adjuster.
    But the result still remain the same.
    anybody can help me to guide me in adjusting the condition above?
    thanks a bunch for your great help.

    Miss Liana

  2. #2
    Join Date
    Jul 2006
    Location
    The Great country of Texas
    Posts
    429
    How did you get a subcooling reading without a liquid line temp on this log?
    "I'm from Texas, what country are you from?"

  3. #3
    Join Date
    Feb 2003
    Location
    Wichita Ks
    Posts
    1,477
    a exv does not have a adjuster screw on it.
    did you check all sensors for accurate readings?
    both evap and cond approach is too high.
    you need to get an exp tech on that machine.

  4. #4
    Join Date
    Nov 2009
    Location
    Jakarta
    Posts
    2
    Sorry, the Liq L Temp is 82.4
    Last edited by Liana; 11-18-2009 at 09:00 PM.

  5. #5
    Join Date
    Feb 2002
    Posts
    181
    I wouldn't do anything until the Lvg. CHW was down to setpoint

  6. #6
    Join Date
    Jul 2006
    Location
    The Great country of Texas
    Posts
    429
    So your subcooling is 17 degrees? That is a bunch. Did you use your own instrumentation or the micro? I don't trust the micros. If the subcooling is true, it sounds like you are stacking the condenser with liquid. That is the reason for the high SH and high LCW. What type of metering device does it have, piloted TXV to main valve or EXV? R-134a should have around 15 degree discharge SH at full load with liquid injection turned off
    "I'm from Texas, what country are you from?"

  7. #7
    Join Date
    Nov 2007
    Location
    DownUnder
    Posts
    33
    Make sure your flow is correct and check your gas charge. It appears to be at full load but not doing much delta T.

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