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  1. #27
    Join Date
    Apr 2012
    Location
    Louisiana
    Posts
    744
    Quote Originally Posted by KnewYork View Post
    Not a very good idea when there is no load. The thing will cycle itself to death as pointed out earlier.
    Op said it spent 30 mins at 32 degree return with machine off. If that's true why couldn't you shut down at 32 an bring it on at 40 or more? Wouldnt that be better than leaving it on with no load? Im not very experenced with centrifugals. Op hasn't stated how critical supply temp is.

  2. #28
    Join Date
    Jun 2006
    Location
    Omaha, Nebraska
    Posts
    869
    In the late '90s I ran a plant with (2) 750 ton Trane Centrivacs. Sometimes the load would drop off when the outside temp fell suddenly and the AHU's started running mixed air. I'd sit there in the engineering office and hear the lead machine cycle off. If the LWT came up after a while it would restart. What a concept. Those chillers had no bells or whistles. No Variable Speed Drive, no Solid State Starter, no Hot Gas Bypass, no Variable Geometry Diffusers, no Optiview, actually a very simple design. They're still running to this day, years later and the only time I ever heard one surge was if the condenser water went above 86F. Then all I had to do was raise the CW Setpoint a bit. I never even knew what a Rotating Stall was until I encountered these YK machines.

    Maybe the YK is a great machine. Maybe they are misapplied at this plant. I don't work on centrifugals often, but I would think in 20+ years I would have encountered this problem on other machines but I have not.

    No one ever answered my question about why the machine has a Disable Setpoint if it is incapable of making chilled water colder than the setpoint. Why not just have a single LWT setpoint and leave it at that? It never cycles off no matter what. And since my name is on the log it is very relevant to me if a 6 month old compressor shells out.

  3. #29
    Join Date
    Jan 2011
    Posts
    1,223
    Quote Originally Posted by man from trane
    No one ever answered my question about why the machine has a Disable Setpoint if it is incapable of making chilled water colder than the setpoint. Why not just have a single LWT setpoint and leave it at that? It never cycles off no matter what.
    The chiller you have was selected by someone to perform a certain function. We don't know how or why it was selected. I will guarantee you that any of the former York (or present JCI) guys who frequent this site could get that machine to behave (and shut off). A thorough understanding of the various components and programming of the Optiview panel come into play when a machine isn't performing. You aren't dealing with a standard comfort cooling machine like those old CVHEs. Yorks will cycle just like those CVHEs when applied in a comfort cooling application. You have a more complex system and the system (outside the chiller) isn't doing what its designed to do and you're blaming the chiller. You even stated in your original post that they are having problems with their process.

  4. #30
    Join Date
    Jun 2006
    Location
    Omaha, Nebraska
    Posts
    869
    I would like to see the JCI tech get it to cycle off. Are there some hidden parameters I can't see from service mode? Even the service manual says it's doing what it's supposed to by not opening the HGB unless there's a surge condition. JCI won't be coming back here unless there is a major issue that we can't handle. That's why I would like to be able to correct this without getting them involved.

    In another part of the building there are (2) smaller YK chillers used for HVAC that also do not cycle off. But they will sit and surge rather than stall.

  5. #31
    Join Date
    Dec 2008
    Location
    Dixiana, AL
    Posts
    2,611
    Quote Originally Posted by man from trane View Post
    I would like to see the JCI tech get it to cycle off. Are there some hidden parameters I can't see from service mode? Even the service manual says it's doing what it's supposed to by not opening the HGB unless there's a surge condition. JCI won't be coming back here unless there is a major issue that we can't handle. That's why I would like to be able to correct this without getting them involved.

    In another part of the building there are (2) smaller YK chillers used for HVAC that also do not cycle off. But they will sit and surge rather than stall.
    I'm not with York anymore (never did consider myself to be with jci), but if you'll get me a PO I'll come to Omaha and show you how. I'm not cheap, but I'm easy

  6. #32
    Join Date
    Sep 2007
    Location
    Somewhere in the world.
    Posts
    1,618
    This entire discussion is explained in great detail in IOM 160.54-m1 this thread should be in the pro forum.
    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 !

  7. #33
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,526
    Quote Originally Posted by klove View Post
    I'm not with York anymore (never did consider myself to be with jci), but if you'll get me a PO I'll come to Omaha and show you how. I'm not cheap, but I'm easy
    i am 2 hours from omaha...1:30 if there aren't any cops!
    "If you pull one more stunt like you just pulled with Tommy, you won't have to get on a plane because I will personally kick your ass from here to Korea!" - Best of the Best

  8. #34
    Join Date
    Jun 2006
    Location
    Omaha, Nebraska
    Posts
    869
    That might not be out of the question!

  9. #35
    Join Date
    Jun 2012
    Location
    so cal
    Posts
    22
    hot gas will open up at 1 degree below leaving chilled water set point unless you set it to 2 then it will be 2 below set point and so on....

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