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Thread: DDR

  1. #14
    Join Date
    Feb 2008
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    i did not see this mentioned, but you would like to see a differential of 25#-30# between the differential valve wether it is in the discharge or liquid line. with the valve de-energized and no systems in defrost.

  2. #15
    Join Date
    Sep 2008
    Western PA
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    Not to pick a fight, but I normally set them to 18-20 psid and our customers that provide settings and specifications require than range. If you go much higher than that with a liquid line differential valve, you will wind up pumping the rack down and any open type cases that you have can starve for refrigerant and go warm on you. That can be a bear of a problem to track down without a rack controller with graphing capabilities, because the problem is GONE by the time you get there.

    I have set them up in the 25-30 range before and have had only problems.

    On the discharge regualtors, you can get away with a setting that high, but it really is unnecessary. 20 psid is an adequate differential unless you are running extremely long lines.

    Try the lower differential and the liquid line temperature test that I described. By lowering the differential, you may need to extend defrost times a couple of minutes, but your rack will run more stable and more efficiently.

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