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  1. #1
    Join Date
    Feb 2008
    Location
    Dubai
    Posts
    107

    Confused CARRIER 30GH CHILLER-FLOODING AND NOT MAINTAIN DELTA-T

    Dears,

    I have chiller carrier 30GH 245 prodialog control systems. When circuit B is running at full load (4 compressors are running), delta T does not maintain, if the EWT is 13c LWT will be 12c.also all compressors are flooding. Checked flow, strainer..Etc. everything ok. The next thing is the superheat is 22c, so the EXV is 95% open. Replaced compressor sensor, and transducer value is correct. So I have doubt about the heatxchanger gasket whether damaged. Anybody has such experience; your any comment would be appreciated.

    thanks
    moideen-Dubai

  2. #2
    Join Date
    Dec 2011
    Location
    Australia
    Posts
    18
    Have you checked EWT and LWT sensors for calibration? How are the compressors flooding with 22k superheat? What is the problem, is it the flooding or not reaching LWT setpoint?

  3. #3
    Join Date
    Feb 2008
    Location
    Dubai
    Posts
    107
    Quote Originally Posted by syk35 View Post
    Have you checked EWT and LWT sensors for calibration? How are the compressors flooding with 22k superheat? What is the problem, is it the flooding or not reaching LWT setpoint?
    ewt and lwt sensors are ok.22 k is the compressor superheat not evaporator superheat.as per the catalouge superheat setpoint is 16c,so 22k is also little high. but upto the bottom side of the compressor head is flooding.

  4. #4
    Join Date
    Dec 2011
    Location
    Australia
    Posts
    18
    I don't understand how you could have liquid refrigerant flood back to the compressor with 22k superheat. 22k superheat means that the refrigerant is superheated 22k above saturation temperature. I think that we need to know all the stats here. Suction pressure, head pressure, refrigerant type, liquid line temperature, suction line temperature at end of the evaporator and entering the compressor, EWT, LWT. Maybe attach a picture of the problem as well?

  5. #5
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    2,064
    I would verify the accuracy of all temperature sensors related to superheat control/indication. When you say compressor superheat, is that discharge superheat?

  6. #6
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,718
    I would start at the first compressor there could be mechanical issue. Run B1 by itself and slowly add compressor stages to the circuit.

    Log system at each stage of the process and your problem will probably show up.

  7. #7
    Join Date
    Feb 2012
    Location
    utah
    Posts
    106
    I don't get that statement, "but up to the bottom side of the compressor head is flooding" what do you mean by that and how can you tell. if you have superheat you are not flooding. I think I know where your going but you need to give some more info.

  8. #8
    Join Date
    Feb 2008
    Location
    Dubai
    Posts
    107
    thanks your comments.
    The EXV of the 30 GH chiller is not controlled with the evaporator superheat unlike other chillers. Suction gas temperature thermistor located in the lead compressor in each circuit in a suction passage after the refrigerant has passed over motor and is about to enter the cylinder. These machines are set up to provide approximately 3 to 4c superheat leaving the cooler. Motor cooling account to 12c. These chiller will trip on high suction superheat when the SH is greater 42c if EXV is 97%open.
    I have committed a mistake that the thermistor I used for suction gas is not correct sensor. I used 30gtn chiller sensor. Part number is deferent.GH sensor value is 17 Kilo ohms at 10c, GTN value is 31kilo ohms. Tomorrow I will replace the correct sensor. You all are correct, when 22k superheat compressor will not flood. But this value was wrong. Anyway I would update after replacing the sensor.

  9. #9
    Can Someone provide me O&M Manual for 30GH 220 chiller

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