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  1. #1
    Join Date
    Jan 2012
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    Pakistan
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    20

    York Chiller - Low Evaporator Pressure Tripping

    We have three York centrifugal chillers with the following spec
    Series YT Codepak
    Unit Model YTH3J3E35COG
    Refrigerant R123
    Capacity 500 Tons
    Compressor Model YDTL.126
    Starter SSS 26L-50A (LCSSS)

    As per the design, the chiller should trip on Low Evaporator Pressure (falling 5.42psi). One of the chiller does not trip on this particular value (even lower) than this.

    I've changed a few cards but to no avail. Can anyone guide me as to what could be the problem.

  2. #2
    Join Date
    Aug 2000
    Location
    Austell, Ga.
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    1,296
    Depending on the Micro-Panel you have, it is possible that either the "Ice-Mode" jumper has been removed or cut on some Micro-Panels giving you a whole new set of shutdown parameters. If not that the I would guess the Micro-Panel itself has gone south "Assuming" that the Evap. Pressure transducer is working as advertised. You "Will" need a very good pressure gage to verify the output on that transducer. The Service mans gages just ain't good enough for that.
    Good luck and keep us posted on this one please.
    Ain't "None" of us as smart as "All" of us..

  3. #3
    Join Date
    Jan 2012
    Location
    Pakistan
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    Quote Originally Posted by RichardL View Post
    Depending on the Micro-Panel you have, it is possible that either the "Ice-Mode" jumper has been removed or cut on some Micro-Panels giving you a whole new set of shutdown parameters. If not that the I would guess the Micro-Panel itself has gone south "Assuming" that the Evap. Pressure transducer is working as advertised. You "Will" need a very good pressure gage to verify the output on that transducer. The Service mans gages just ain't good enough for that.
    Good luck and keep us posted on this one please.
    We're using this micro board (PN 031-01065-001). I've swapped a "good" micro board (from a chiller which does trip on 5.42 low evap) into this one, but have yet to test it out.

    About your second point, the transducer only gives out a 0.5 to 4.5v signal against the pressure and not the tripping so how is that related?

    Btw, the transducer is fine, I had already checked that on a different unit.

  4. #4
    Join Date
    Jan 2012
    Location
    Pakistan
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    Just tested the chiller with the new/swapped Microboard and it does trip with that.

    One observation, there was a selector on the board, on one of the boards it was set to '1' and in the other it was set to '3'. Any idea what that could be?

  5. #5
    Join Date
    Sep 2007
    Location
    Somewhere in the world.
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    Quote Originally Posted by snsici View Post
    Just tested the chiller with the new/swapped Microboard and it does trip with that.

    One observation, there was a selector on the board, on one of the boards it was set to '1' and in the other it was set to '3'. Any idea what that could be?
    If rotary dial that setting would be for address.
    Arguing with your Boss is like wrestling with a pig in
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    After a while you realize that while you are getting
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  6. #6
    Join Date
    Jan 2012
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    Pakistan
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    Quote Originally Posted by york56 View Post
    If rotary dial that setting would be for address.
    Yes rotary dial setting, 1,2 and 3. But address of what?

  7. #7
    Join Date
    Jan 2012
    Location
    Pakistan
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    Quote Originally Posted by snsici View Post
    Yes rotary dial setting, 1,2 and 3. But address of what?
    Its a rotary dial from 0-9. And S1 is written besides it. What exactly is it?

  8. #8
    Join Date
    Sep 2007
    Location
    Somewhere in the world.
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    1,614
    It is a Chiller ID switch as you had said you may have 3 Chillers there not sure ? everyone is set to a different number thats its address most likely there is a microgateway somewhere there or some type of automation system that is communicating to it to pull some type of information or giving commands to run or enable again I am not there nor am I lookin at it I am just giving some insight as to what might be attached to it.
    Arguing with your Boss is like wrestling with a pig in
    mud.
    After a while you realize that while you are getting
    dirty, the pig is actually enjoying it.

    It is not exactly cheating, I prefer to consider it
    creative problem solving.

    25 years ago we had Bob Hope , Steve Jobs , and Johnny Cash today we have no Hope no Jobs and no Cash !
    I can fix broke but i can't fix stupid !

  9. #9
    Join Date
    Jan 2012
    Location
    Pakistan
    Posts
    20
    Well we do have 3 Chillers although no automation or any such thing in place. Anyways I did change that but to no effect.

    Any other ideas on what could be the solution other than, ofcourse, getting a new one which I am ordering.

  10. #10
    Join Date
    Jan 2012
    Location
    Pakistan
    Posts
    20
    Solved the problem. There was a jumper "JP2" which was cut on this faulty board while intact on the other two. Just jumped it and voila, it trips.

    Thanks for the help guys.

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