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Thread: Trane 100 Ton

  1. #1
    Join Date
    Apr 2004
    Location
    Napoleon, Ohio
    Posts
    47

    Hmm Trane 100 Ton

    Trane Model RTAA1004XM01A3D0BG
    Serial U01E00721


    Chilled Water Flow (Ent Wtr Temp) lock out fault
    This is the issue I'm having today with the 100 Ton unit at my automotive factory. I have checked my manual and it explains that the entering evaporator water temp drops below the exiting water temp. Simple enough. I can clearly see it do so within 30 seconds of starting circuit 2. The exit temp barely fluctuates and the entrance temp starts dropping fairly fast after the compressor starts.

    I don't appear to have a flow issue, all of the pumps are fine, flow switch is working, and most importantly I can lockout circuit 2 and run circuit one and all is well.

    There is one water temp sensor at the entrance and one at the exit to the evaporator, so I am ruling out a sensor issue because both compressors use the same sensors for temps.

    I let circuit one run and cool all of the water down so the equipment could run in the facility. After the water was cooled to it's set point, I started circuit 2 alone and it acted exactly the same, faulting within seconds.

    I have ran the EXV service test and everything seems to react the same between the 2 circuits. (The test only involves listening for clicks and timing the pauses between them as the machine cycles them closed and open).

    I can't help but think there is an issue with the EXV or something restricting refrigerant flow.

    Anybody have any advice to help me out?
    Thank you.

  2. #2
    Join Date
    Jan 2005
    Location
    Houston TX
    Posts
    874

    Just a wild guess

    sds5150 I would be looking at the depth and placement of the entering water sensor, with regard to the #2 circuit refrigerant tubes. The sensor could have been installed too deep. You may have crossed over sensors (ie) circuit #2 suction or evaporator sensor miswired to the entering chilled water position on the chiller module. Good luck-GEO
    Once in a while everything falls into place and I am able to move forward, most of the time it just falls all over the place and I can't go anywhere-GEO

  3. #3
    Join Date
    Apr 2004
    Location
    Napoleon, Ohio
    Posts
    47
    The system has been running for over a year without any issues and I'm the only one that works on it besides a company from outside my facility (and I would know if they where in). It would seem that a problem like what you described would have appeared long ago. Thank you very much I appreciate the input.

  4. #4
    Join Date
    Aug 2010
    Location
    Memphis
    Posts
    343
    Sensors could be reversed? Ohm out sensors to see if reading correct temps. Also have seen RTAAs do that if evap bundle is dirty.

  5. #5
    Join Date
    Feb 2010
    Location
    MEXICO
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    which is the inlet temperature of the water? if less than the output water temperature causes the machine to stop this is to prevent freezing does not operate the water flow switch

  6. #6
    Join Date
    Apr 2004
    Location
    Napoleon, Ohio
    Posts
    47
    The 2 compressor circuits share the same evaporator and the same water temp sensors.

    When I start compressor 1 ALONE the leaving water temp drops and everything runs great.

    When I start compressor 2 ALONE the watering entering temp drops, the leaving water temp doesn't change much, then it faults.

    1 Water entering Evap sensor for the entire dual compressor system and
    1 Water leaving Evap sensor for the entire dual compressor system

  7. #7
    Join Date
    Mar 2010
    Location
    Va.
    Posts
    180
    Check pressure drop across the evaporqator and make sure it meets minimum requirements. You can't go by the flow switch. Give the entering and leaving temperature sensors a 32* bath one at a time and see if they match the entering and leaving temperatures on the display. Make sure the readings are a steady 32* with no fluctuations. The sensors are the same for both circuits so I can't see why Circuit 1 will run and cicuit 2 won't. Circuit 2 is closer to the entering and leaving connections and might show up with low water flow before circuit 1.

  8. #8
    Join Date
    Apr 2004
    Location
    Napoleon, Ohio
    Posts
    47
    Phisher,
    Thank you. I'll check those things out. Yeah, the fact that circuit 1 runs great threw me too. I suspected something on the refrigerant side of circuit 2, that's why I posted for some expert advice. Thanks again.

  9. #9
    Join Date
    Feb 2010
    Location
    MEXICO
    Posts
    472
    so it is a pair of sensors for the two compressors, obviously you have a water flow problem. is not normal to the inlet temperature is lower than salida.es why it protects the machine. another reason is that the temperature sensor in contact with the sense fluxeria and coolant temperature

  10. #10
    Join Date
    Mar 2010
    Location
    Va.
    Posts
    180
    If your flow is correct and it's a refrigerant issue you should be getting a refrigerant type diagnostic not the entering water diagnostic. Good luck. Minimum flow is 120 gpm/ 4.09# deltaP (Pg. 22 RTAA-IOM-4A for a 100ton chiller)

  11. #11
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,044
    When the chiller cycles off on demand , does the pump stop too??? If so then the leaving cold water will migrate back to the inlet of the evap and give the diagnostic next time the chiller starts .
    Or is this a primary secondary loop with bypass ????
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
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  12. #12
    Join Date
    Apr 2004
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    Napoleon, Ohio
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    47
    Graham,
    The pumps move water through the evaporator all the time, 24/7.

  13. #13
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,342
    Quote Originally Posted by Phisher View Post
    ...Circuit 2 is closer to the entering and leaving connections and might show up with low water flow before circuit 1.
    number one answer on the board! the water passes over the circuit #2 tubes first, then the sensor, then the #1 tubes, then it alternates back and forth between the tubes. low water flow causes all kinds of issues. i am surprised that you don't have problems with circuit #1.

    the actual minimum pressure drop is 4.0 FEET OF WATER (about 1.73 psid) but i think that the REAL minimum is closer to 3-4 psid...sometimes i think trane allows the marketing department into the engineering department too much.
    "Mother" is the name for God on the lips and hearts of children....The Crow

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