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Thread: mcquay ags175 air cooled screw chiller exv/ microtech II question

  1. #1
    Join Date
    Jan 2015
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    mcquay ags175 air cooled screw chiller exv/ microtech II question

    hi there, not sufre if anyone can help but i have a question regarding microtech II mcquay controllers and their relationship to the exv. one stage on this chiller the exv will not open up. i have tested the exv and it works, but when the main microtech calls for pre open the exv position stays at 0000 on the screen. From what i understand it needs to drive to 3000 for pre open... stage two is doing this stage one is not. no power coming out of microtech to exv board either due to this.

    i am wondering if this is due to some programming being missing out of the microtech or if i am missing something?

  2. #2
    Join Date
    May 2019
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    Check Evaporator pressure transducer...

  3. #3
    Join Date
    Apr 2020
    Location
    va
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    Does the exv work in test mode from the microtech?

    As the valves age, some have worked with low/no dp , but not with operating dp.

    Signal from mt 2?

  4. Likes Papai Santra liked this post.

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