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  1. #1
    Join Date
    Oct 2011
    Location
    East Charlotte Area of NC
    Posts
    375

    Unhappy Old Kysor/Warren Rack, Mechanical Pressure Control Staging Settings.. Help?

    Would Like some advice on what set points to use on setting up staging of the compressors on an older rack I am serviceing.

    Its an old Kysor/Warren (or Sherrer.. cannot remember right now) that runs on mechanical controls. The rack had been running wide open for who knows how long. A quote is currently being worked up for an Einstein controller for both racks at this store, but int he mean time, I would like to get the compressors cycling on mechanical.

    It's R222, 20deg suction header. (43psig)

    Compressors:

    All Copeland

    2 3DS3R17ME. This compressor is listed on copelands OPI as a HT comp at 116,000btu. They are 10 HP comps.

    1 3DS3F46KE. This compressor is listed on copelands OPI as a LT comp at 37,500btu. It is 7HP

    1 3DB3A100E. This actually is a MT compressor. 87,000btu. 7.5HP

    So. Any suggestions other than changing the 3 compressors to MT compressors?

    Thanks in advance!

    I can't fix it if it won't stay broke..

  2. #2
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,085
    Here's the Kysor/Warren I&O Manual:

    http://www.kysorwarren.com/docs/uplo...07_Systems.pdf

    What you're looking for may (or may not) be in there.

  3. #3
    Join Date
    Oct 2011
    Location
    East Charlotte Area of NC
    Posts
    375
    Did not have what I needed for this issue, but helped clear up another. Thanks.

    I can't fix it if it won't stay broke..

  4. #4
    Join Date
    Dec 2006
    Location
    In a Mess
    Posts
    992
    i dont think you have to change any pumps

    his would be my opinion, run the 3DS3F46KE as #1 lead pump cut in 30 out 10

    stage the 2 3Ds3's as #2 and #3 and set the 3DB3A as #4

    try
    #2 at in 43 out 38
    #3 at in 45 out 40
    #4 at in 47 out 42

    what ever you find and try you will have to monitor the operation and make sure your defrosts are spaced properly, i would also run the pressure controls from the suction header and not the compressor bodies. i would also set controls with N2 and digital gauges, works better, even if you have johnson microset controls its hard to use the numbers on the control.

    Mike
    Sig removed by mod. G-Rated site

  5. #5
    Join Date
    Oct 2011
    Location
    East Charlotte Area of NC
    Posts
    375
    Thanks, I'll try that when I get back to it next week. The settings are a bit tighter than I would have put them, which is why I asked for help!

    If the customer does not go for the E2 install, we are going to put the microset controls on it, just was not sure of the proper setup.

    Does anyone know of a simple digital controller that will stage the compressors? I know the best route is an E2 or similar, but wasn't sure of other options.

    I can't fix it if it won't stay broke..

  6. #6
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,085

  7. #7
    Join Date
    Sep 2006
    Location
    Chicago
    Posts
    474
    Who makes them electronic t-stats you see on older condensers for fan cycling? The ones with 1 pressure transducer and you can link the electronic controls all together. If you gotta go without cpc this may be easier and more accurate. Just a thought.

  8. #8
    Join Date
    Dec 2006
    Location
    In a Mess
    Posts
    992
    Quote Originally Posted by dangpgt97 View Post
    Who makes them electronic t-stats you see on older condensers for fan cycling? The ones with 1 pressure transducer and you can link the electronic controls all together. If you gotta go without cpc this may be easier and more accurate. Just a thought.
    are you referring to the JOhnson 450 series possibly??

    Sig removed by mod. G-Rated site

  9. #9
    Join Date
    Sep 2006
    Location
    Chicago
    Posts
    474
    Found it.

    System 350 Pressure Controls

    http://www.johnsoncontrols.com/publi...rols/p352.html

    I think these would work.

  10. #10
    Join Date
    Dec 2010
    Location
    Central US
    Posts
    394
    Not impressed with the 450 series, 350 series im a believer.

  11. #11
    Join Date
    Apr 2010
    Location
    Richmond, Virginia
    Posts
    304
    Just installed a new altech cheap worked great for just staging the compressors!!

    http://www.altechcontrols.com/mcc.asp

  12. #12
    Join Date
    Dec 2011
    Location
    USA
    Posts
    66
    Raise the suction cut-in just as high as you can and still maintain temperatures. For example a 20 rack running R-22 I would give it a cut-in of #44 and let the Alteh do the work. This will allow the compressors to cycle and keep the temp.

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