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  1. #1

    microzones and fan status

    Hey guys i am fairly new to hvac so bear with me.

    I am working on a site using microzone ii controllers. The bms is showing a fan failure on the unit while being commanded on. I went to the unit and the fan is running fine. I am use to seeing a current switch on the unit which sends the signal to the bms showing that the fan is running.

    They are telling me here there is no such current switch.

    What am i missing that is ovbiously not working to show status.

  2. #2
    i am looking for a pressure switch after the supply fan an cannot find that either.

  3. #3
    Join Date
    Apr 2012
    Location
    Paper Street Soap Company
    Posts
    2,304
    It might be a fan relay failure ( contacts welded shut ), a control module out put failure.

    Or there could be a differential pressure switch sending the input back ( unlikely ) or your zones are mixed up.

  4. #4
    Join Date
    May 2009
    Location
    in the present
    Posts
    92
    Does the fan have a VFD? If so fan status would probably come from one of the status relays in the drive,

  5. #5
    Join Date
    Mar 2008
    Location
    NC
    Posts
    1,461
    Sounds like you need to find the drawings, or go to the controller and start following wires.

  6. #6
    Join Date
    Jun 2006
    Location
    New Jersey
    Posts
    4,340
    Maybe that's the problem.........no one ever installed anything to prove the fan?

  7. #7
    Join Date
    Jul 2011
    Location
    East coast USA
    Posts
    997
    check and identify your DI points on the controller, What does your other Microzones say on the front end? do you have a front end? its either an amp ring or pressure switch but must likely an amp ring.

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