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  1. #1
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    Frosted compressor w/ suction accumulator

    Hi guys,

    This is a theoretical question. It's not my installation.

    I took a photo of a compressor unit with suction accumulator installed.
    Name:  20200129_052113.jpg
Views: 264
Size:  129.6 KB

    Why is the compressor frosted although there is a suction accumulator present in a system?

  2. #2
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    The theoretical answer is by having a surface temperature below 32f.

    Maby the accumulator is full because of an overcharge and or evap fan failure.
    Quote Originally Posted by BobFrost View Post
    Hi guys,

    This is a theoretical question. It's not my installation.

    I took a photo of a compressor unit with suction accumulator installed.
    Name:  20200129_052113.jpg
Views: 264
Size:  129.6 KB

    Why is the compressor frosted although there is a suction accumulator present in a system?
    Sent from mars using Tapatalk

  3. #3
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    Just suppose that this is a freezer. Just suppose that the box temp is -12*F and also suppose that the TXV is set for a 6*SH. So I suppose that the "vapor only" refrigerant leaving the evap is also "liquid free",and at a temp of -6*F, meaning that the accumulator is not being used as a temporary liquid holding tank because there is no liquid to be held in the accumulator,at this time. Now suppose that the -6*F freon inside the suction line has some moisture in the air on the outside of the suction pipe. I now supposed that the moisture in the air would now FREEZE out of the air causing a frosted suction line and possible/probably/more than likely a frosted comp, I think. So it is very possible that the frost is normal.

    But on the other hand, if this a med temp box, then they have some major problems.

  4. #4
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    Thread Starter
    I believe it's a LT application because there is a head fan installed.

  5. #5
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    Let's suppose that TechmanTerry is correct and that he gave a very good explanation.
    If at First You Don't Succeed, Skydiving Is Not for You.

  6. #6
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    Quote Originally Posted by TechmanTerry View Post
    Just suppose that this is a freezer. Just suppose that the box temp is -12*F and also suppose that the TXV is set for a 6*SH. So I suppose that the "vapor only" refrigerant leaving the evap is also "liquid free",and at a temp of -6*F, meaning that the accumulator is not being used as a temporary liquid holding tank because there is no liquid to be held in the accumulator,at this time. Now suppose that the -6*F freon inside the suction line has some moisture in the air on the outside of the suction pipe. I now supposed that the moisture in the air would now FREEZE out of the air causing a frosted suction line and possible/probably/more than likely a frosted comp, I think. So it is very possible that the frost is normal.

    But on the other hand, if this a med temp box, then they have some major problems.
    Good explanation, but you forgot to include the evaporator TD.

    So assuming a -12F box temp and a 10F TD, the SST would be -22F.

  7. #7
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    Quote Originally Posted by BobFrost View Post
    Hi guys,

    This is a theoretical question. It's not my installation.

    I took a photo of a compressor unit with suction accumulator installed.


    Why is the compressor frosted although there is a suction accumulator present in a system?
    As explained earlier, frost doesn't always mean floodback. Here's a pic of a supermarket rack with a measured 28F of suction superheat...ie, textbook normal conditions for the application:

    Name:  FrostedRackwith28degSHbySmilies.JPG
Views: 221
Size:  22.3 KB

  8. Likes Andrew Schaefer, COOLJIM liked this post.
  9. #8
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    As long as the oil sump is warm! If that is cold you have floodback

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