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  1. #14
    Join Date
    May 2010
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    1,295
    ARGH!!! I don't know why I dont have the edit function available in this forum, BUT....

    I should also state that when switching Chiller #1 to the "Setpoint Source: BAS/Ext/FP" it doesn't shut down and operates in that mode just fine. I have yet to try putting them both in that mode simultaneously.

  2. #15
    Join Date
    Oct 2003
    Location
    Michigan
    Posts
    726
    "Setpoint Source: BAS/Ext/FP" should only arbitrate where the CW Setpt comes from. First would be BAS which is a communicated Setpt from the BCU. Second if no BAS Setpt is available use an external control source. Third if no BAS or External is available use the Setpt from the front panel. It should not shut down the chiller.

    What control is on these chillers? CH530, Adaptiview or other?

    You need to find out what is shutting the chiller down on the chiller status page, it should state some type of run inhibit from a "control source". Also what is controlling the chiller start command, is it "Chiller Plant Control" from the BCU or an external relay controlled by Alerton?

    Also what has changed for this to start happening between 2007 and now?
    Beware of the prophet trying to make a profit.

    There is less oxygen from knee level to the floor! Check it out next time you tie your boots.

  3. #16
    Join Date
    May 2010
    Posts
    1,295
    Yes, it is a CH530.

    I can either stop/start the chillers via the remote relay which gets its signal from the Alerton VLX (Plant Controller) or when the chillers are set to "Setpoint Source: BAS/Ext/FP" I can tell Alerton Envision (program) to talk directly to the Trane Tracer Summit via a BACnet object and start/stop the chillers that way.

    I am trying to figure out why Chiller #1 is shutdown when switched to the "Setpoint Source: BAS/Ext/FP" and why Chiller #2 doesn't when in the same mode. I am wondering if it has to do something with #1 being a lead chiller or what the problem is.

  4. #17
    Join Date
    May 2010
    Posts
    1,295
    In 2007 they set the chillers up to start/stop off the external relay from the very beginning when they were installed, because Cohesive says the BAS mode was unreliable when they tested it.

    Now in 2012, I am wanting to control my Setpoints from the EMS Computer and not at the Front Panel of the Chillers like they have done since 2007.

  5. #18
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    2,067
    The chiller WOULD shut down when placed in "Setpoint Source: BAS/Ext/FP" IF there is a BAS or Ext setpoint present AND that setpoint is high enough above the FP setpoint so as to cause the chiller to believe itself "satisfied" and initiate a "normal" shutdown. And to complicate matters, there is no designation for a normal shutdown - there would be be no indication of why the shutdown occurred, followed by "Waiting to cool" (or something to that effect).

  6. #19
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    2,067
    Could this be a lead/lag issue, with adding the lag chiller based on return chill water temp?

  7. #20
    Join Date
    Oct 2003
    Location
    Michigan
    Posts
    726
    Quote Originally Posted by Nuclrchiller View Post
    The chiller WOULD shut down when placed in "Setpoint Source: BAS/Ext/FP" IF there is a BAS or Ext setpoint present AND that setpoint is high enough above the FP setpoint so as to cause the chiller to believe itself "satisfied" and initiate a "normal" shutdown. And to complicate matters, there is no designation for a normal shutdown - there would be be no indication of why the shutdown occurred, followed by "Waiting to cool" (or something to that effect).
    Agreed
    Beware of the prophet trying to make a profit.

    There is less oxygen from knee level to the floor! Check it out next time you tie your boots.

  8. #21
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    2,067
    I ask the above because my other bldg has non-Trane eqpt and the controls bring on lag chiller based on increased return temp. And if lead chiller fails, lag chiller is started, but satisfies the return temp call for lag and is shut down by BAS. Lag chiller is not rotated to lead. And the lag chiller short-cycles, until I catch it.

  9. #22
    Join Date
    Oct 2003
    Location
    Michigan
    Posts
    726
    Quote Originally Posted by ZeroTolerance View Post
    In 2007 they set the chillers up to start/stop off the external relay from the very beginning when they were installed, because Cohesive says the BAS mode was unreliable when they tested it.

    Now in 2012, I am wanting to control my Setpoints from the EMS Computer and not at the Front Panel of the Chillers like they have done since 2007.
    In 2007 you could remotely change the Setpt but today you can not. Something has changed or failed and I highly doubt it is a "Communication" issue. The only things that should shut that chiller down is the external relay controlled by others, the CW Setpt is satisfied or a chiller diagnostic.
    Beware of the prophet trying to make a profit.

    There is less oxygen from knee level to the floor! Check it out next time you tie your boots.

  10. #23
    Join Date
    Oct 2003
    Location
    Michigan
    Posts
    726
    Quote Originally Posted by Nuclrchiller View Post
    I ask the above because my other bldg has non-Trane eqpt and the controls bring on lag chiller based on increased return temp. And if lead chiller fails, lag chiller is started, but satisfies the return temp call for lag and is shut down by BAS. Lag chiller is not rotated to lead. And the lag chiller short-cycles, until I catch it.
    Good point since the plant is controlled by a Non-Trane controller. Same thing only different.
    Beware of the prophet trying to make a profit.

    There is less oxygen from knee level to the floor! Check it out next time you tie your boots.

  11. #24
    Join Date
    May 2010
    Posts
    1,295
    Our chillers turn on/off lag chillers based on Chiller Load (avg.) and CHWS.

  12. #25
    Join Date
    May 2010
    Posts
    1,295
    qtip..... In 2007 Cohesive tried to allow the chillers to be controlled via BAS. They were unsuccessful so the building engineers at that time controlled it the same from the day the chillers were installed to now.

    I have only been with this company 2months and am trying to figure out what problems they were having with the BAS (remote control) the moment they were installed so that we can control them via our EMS computer.

  13. #26
    Join Date
    May 2010
    Posts
    1,295
    All of our "Program Hold Delays" (adding and subtracting a chiller) are controlled by the Alerton VLX (plant controller).

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