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  1. #1
    Join Date
    Mar 2007
    Posts
    46

    YORK YT "Loss of serial communications"

    My name is Greg. I work with Oregon State University's refrigeration department.

    We have a 600 ton York YT centrifugal chiller with a variable speed drive.

    Quite frequently it is tripping on "Loss of serial communications with VSD". We have checked the conductor connections and board plug-ins. We have followed a York field tech bulletin on ensuring the grounds are clean, used the star washers, and have made sure only one end of a shielded conductor's shield is attached to ground. Sometimes it can go for months with no problems. Other times it is several times a day I have to restore it. I can watch the lights (RX/TX Rcd) on the board the VSD talks to blink regularly, and then they don't blink or not in a regular pattern and then the chiller controller initiates a shut down.

    Anyone have experience or has fixed something like this? At a couple grand a board I don't want to blindly swap parts.

    Thanks

  2. #2
    Join Date
    Sep 2007
    Location
    Somewhere in the world.
    Posts
    1,613

    Serial comm failures

    Put your email in your signature and I will send you some info.
    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 !

  3. #3
    Join Date
    Jul 2010
    Posts
    59
    good luck buddy! i have the same problem with a 2000 ton YST. The problems come and go. usually we will find a lose plug and think we cured it...

  4. #4
    Join Date
    Mar 2007
    Posts
    46
    email in your signature
    Done. Just click my name.

  5. #5
    Join Date
    Sep 2007
    Location
    Somewhere in the world.
    Posts
    1,613
    I sent them let us know if it helps you out.
    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 !

  6. #6
    Join Date
    Mar 2007
    Posts
    46
    Thank you for the bulletins.

    We went through and put all new star washers in, plus added a few at the interface panel enclosure AND the VSD enclosure mounting bolts. I found one of the two VSD transformers with flat washers for the mounting bolts and replaced them with star washers as well.

    It's definitely bonded this time!

  7. #7
    Join Date
    Sep 2007
    Location
    Somewhere in the world.
    Posts
    1,613
    Did you also follow the instructions for the ACC board and not sure if the Harmonic Filter is a option that is installed if so follow those instruction to.
    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 !

  8. #8
    Join Date
    Mar 2007
    Posts
    46
    instructions for the ACC board and not sure if the Harmonic Filter is a option that is installed if so follow those instruction to.
    If you're referring to moving the communication's shield grounding point from the knock-out(plate) to the main enclosure for the panel; yes we did that the 1st time but we went ahead and did it again this time as well.

  9. #9
    Quote Originally Posted by greg r View Post
    If you're referring to moving the communication's shield grounding point from the knock-out(plate) to the main enclosure for the panel; yes we did that the 1st time but we went ahead and did it again this time as well.

    Question does it get real hot in the mech room that its in? i had a problem with one whenever it was real hot above 95 in the mech room i would have that fault pop up.

  10. #10
    Join Date
    Dec 2008
    Location
    Dixiana, AL
    Posts
    2,611
    Quote Originally Posted by greg r View Post
    It's definitely bonded this time!
    Not necessarily. Run a separate ground wire from the control panel and starter enclosure to the frame of the chiller. 14 ga stranded works nicely.

  11. #11
    Join Date
    Jul 2010
    Posts
    59
    I've been getting random serial communications errors every now and then. Could ambient temperature really be a problem? I'm going to check the temp to or row, but I wouldn't think it was warmer than 85f in my engine room..

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