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  1. #1
    Join Date
    Jun 2009
    Location
    NYC
    Posts
    423

    Temperature control or Pressure control ?

    OK Guys,
    When it comes to med-temp refrigeration (matched or miss-matched units)
    You can control temperature by a temperature control or a pressure control. What's your choice of control when and why?

    I ask this question as my main concern is to prevent ice build-up on coils and eliminating defrost cycles/timers keeping products at a constant temperature.

  2. #2
    Join Date
    Feb 2010
    Location
    NE Alabama
    Posts
    301
    I like temp controls for most, but use pressure controls on R-404-A. 404 Is hard to control in medium temp situations as there is a slim margin of error, and cutoff is so high

  3. #3
    Join Date
    Jan 2010
    Posts
    6,232
    Constant Cut-in type for reach-in applications. Defrost the coil in off cycle.
    Pump down for w/i coolers with remote condenser.

  4. #4
    Join Date
    Oct 2011
    Location
    Hull
    Posts
    53
    When i have to replace an orit in a dual case , my boss whant i replace bye thermostat solenoid but i think controlled temp by pressure is better.

  5. #5
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,567
    What are we talking about specifically?

    A thermostat vs a pressurestat? I'll take a thermostat any day of the week.

    Now, if we're talking about using an ORI pressure regulator valve, I'll take that over either of the above.

  6. #6
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,328
    JP makes a good point about defining what we're discussing here.

    A lot depends upon the application. If your talking about a typical walk-in cooler, then I recommend thermostat & solenoid with pumpdown control and timeclock.

    If it's a self-contained service deli case with a gravity coil, I prefer a low pressure control with a timeclock.

    If you have any system with an outdoor remote condensing unit, that pretty much rules out a pressure control.

  7. #7
    Join Date
    Jun 2012
    Location
    Afghanistan
    Posts
    16
    Johnson Controls has a Digital A419 Temp. control that works great and is very accurate.

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