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freezer with 404a

zepfan
zepfan Member Posts: 430
in A-C, Heat Pumps & Refrigeration

Hello All,

What are the approximate operating pressures, and superheat for a walk in freezer that uses 404a, and has a box temperature of 0 degrees? We do not do a lot of refrigeration work, but have a customer that is looking at a space that has a freezer that recently had a new compressor installed in it. they wanted to make sure that it is operating properly before they take the space. At this point I don't know if it has a TXV or cap tube, but will find out.

thanks to all

Comments

  • mattmia2
    mattmia2 Member Posts: 12,978
    edited June 7

    look at a t&p chart….

    the superheat you basically want as low as possible while still always being positive under all operating conditions. there is more leeway if it has a receiver. if it is a txv that will keep it at a constand superheat as long as there is sufficient refrigerant to do so.

    you can probably learn more by observing how the system is operating than by opening the system.

    zepfan
  • zepfan
    zepfan Member Posts: 430

    @mattmia2 thanks for the response. I actually have more information now then I did when i originally posted. The system isn't working,so we can not observe how it operated when it was working. the compressor is grounded. We need to replace the compressor.

  • mattmia2
    mattmia2 Member Posts: 12,978
    edited June 7

    That's more complicated because it most likely is grounded because it burned out from moisture in the system. Could have been an issue with improper overload protection and failure to start or lost a phase if it is 3 phase but if the system is contaminated because of a burnout that is a different job.

    improper diagnosis is always a possibility too.

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,944

    Freezers usually run at 0to-10 deg and the coil TD is about 10 so look up 404A at -15 to-20 to get your suction pressure.

    zepfan
  • pecmsg
    pecmsg Member Posts: 6,158
    edited June 7

    Copeland wants the SH 6” from the pump between 20 & 40*F.
    Operating pressures vary from manufacturer to manufacturer. If X-valve, Just clear the sight glass.

    zepfan

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