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  1. #1

    rack supermarket system question

    most of my job is Hvac and walkin cooler/freezer and self contain.
    have a chance to visit rack system at safeway for first time.
    the company i work for recently pick up a few supermarket.

    some questions

    - how to rate rack compressor by HP or Tonnage? is it the same rule apply by looking at the model #?
    i've been told model# is only true for copeland.

    - what is procedure to change the removable core dryer and oil? does it need pump down and vacuum after.

    - oil sample, does it need to send to lab

    - where is common way to add refrigerant if needed.


    any advices would help for beginner in rack systems.

    thanks

  2. #2
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    Quote Originally Posted by alpharetta View Post
    most of my job is Hvac and walkin cooler/freezer and self contain.
    have a chance to visit rack system at safeway for first time.
    the company i work for recently pick up a few supermarket.

    some questions

    - how to rate rack compressor by HP or Tonnage? is it the same rule apply by looking at the model #?
    i've been told model# is only true for copeland.

    - what is procedure to change the removable core dryer and oil? does it need pump down and vacuum after.

    - oil sample, does it need to send to lab

    - where is common way to add refrigerant if needed.


    any advices would help for beginner in rack systems.

    thanks
    #1. Copeland's new model numbers don't show the HP as well, or at least I haven't looked up the way to decipher it. Newer controllers are using the actual mBTUh rating of the compressor to select the proper amount of capacity to run.

    #2. Isolate, recover, replace, evacuate and restart. The nice thing is that you've got a HUGE recovery system in place and you can just pump the rack down into itself to do the service.

    #3. We're starting to do more oil sampling than just straight oil changes. Yes, National Refrigerants will do oil testing for a nominal fee.

    #4. Blow it straight in the suction.
    Last edited by jpsmith1cm; 03-17-2013 at 03:05 PM. Reason: typo

  3. #3
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    Quote Originally Posted by jpsmith1cm View Post
    #1. Copeland's new model numbers don't show the HP as well, or at least I haven't looked up the way to decipher it. Newer controllers are using the actual mBTUh rating of the compressor to select the proper amount of capacity to run.
    We actually have a customer in the process of switching controller programming over to using compressor CFM for capacity staging.
    "The problem is the average person isnt tuned in to lifelong learning, or going to seminars and so forth. If the information is not on television, and its not in the movies they watch, and its not in the few books that they buy, they dont get it" - Jack Canfield

  4. #4
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    I wonder...HP, AMPS, CFM, BTUH

    does it matter as long as you're consistent in your setup?

  5. #5
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    Quote Originally Posted by Phase Loss View Post
    I wonder...HP, AMPS, CFM, BTUH

    does it matter as long as you're consistent in your setup?
    Don't think so.

  6. #6
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    Quote Originally Posted by Phase Loss View Post
    I wonder...HP, AMPS, CFM, BTUH

    does it matter as long as you're consistent in your setup?
    I wonder....could you be more of a smarta$$?

    "The problem is the average person isnt tuned in to lifelong learning, or going to seminars and so forth. If the information is not on television, and its not in the movies they watch, and its not in the few books that they buy, they dont get it" - Jack Canfield

  7. #7
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    Quote Originally Posted by markettech View Post
    I wonder....could you be more of a smarta$$?

    I wonder.........

  8. #8
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    Quote Originally Posted by markettech View Post
    We actually have a customer in the process of switching controller programming over to using compressor CFM for capacity staging.
    its just a reference number for the controller. CFM is more accurate because there are can be different cfms being moved by 2 different model 15 HP machines

  9. #9
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    its all about that bore and stroke!
    :P
    Sig removed by mod. G-Rated site

  10. #10
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    I had a cpc engineer sales guy tell me one time that you could put any number in the capacity of a compressor in the suction application, as long as the number represented in some fashion the size of that pump against the other pumps. So say you have 3 equal size compressors and 2 others of different size. You could use single digits. As long as the integer amongst the compressors represented it's size. Comp 1,2,3 have a capacity of 1. Comp 4, capacity of 2 (if it were bigger). Comp 5, capacity of 4.5 (if it were bigger) You can even use .5. .75. The idea is that this is a processor. It's prcoessing math. It's choosing by staging UP and DOWN.

    I did not belive him so he showed me. He was right.
    People who think they know everything are a great annoyance to those of us who do.

  11. #11
    Join Date
    Feb 2007
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    48
    if they are all the same size, you can use what ever kw/hp rating you want, as long as they are all the same. The rating is only used so the controller knows what capacity percent turning the comp on will have. It uses this percent in its algorithm to float the suction pressure.

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