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  1. #27
    Join Date
    Jun 2011
    Location
    NE Ohio
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    966
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    Quote Originally Posted by BBeerme View Post
    By Copeland saying they want no less than 20*F SH at the compressor, they are simply building in a huge safety margin. Nothing more, and nothing less.

    The reality is that you will see a wide variation between applications and temp ranges. For example, the older Manitowoc ice machines were dialed in at 1-2*F evap SH right before harvest. Don't know if they still do that.
    that is why it is nice to understand ' why ', allows you to adapt to different situations

    walk in cooler I service, older circular evaporator coil with a built in heat exchanger, liquid line running about 4 feet inside the suction line ....

    in the summer with a heavy load the unit runs fine with steady evaporator outlet superheat of 10 - 12 degrees

    last winter with a light load the walk in cooler would reach temperature in around 4 minutes, not long enough for the TXV to stabilize, TXV was hunting all over the place and the evaporator outlet superheat was running low at times, figured this must be the low load they are talking about and how the TXV cant maintain superheat, because of the heat exchanger I still had superheat at my compressor so I just bumped up my box temperature a few degrees as an extra cushion so the load wasnt ' as low ', figured who needs ice cold beer in the winter time anyhow

    understanding ' why ' allowed me to adapt to that situation

  2. #28
    Join Date
    Oct 2016
    Location
    Clearwater, Florida
    Posts
    791
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    Thread Starter
    Quote Originally Posted by hvacskills View Post
    that is why it is nice to understand ' why ', allows you to adapt to different situations

    walk in cooler I service, older circular evaporator coil with a built in heat exchanger, liquid line running about 4 feet inside the suction line ....

    in the summer with a heavy load the unit runs fine with steady evaporator outlet superheat of 10 - 12 degrees

    last winter with a light load the walk in cooler would reach temperature in around 4 minutes, not long enough for the TXV to stabilize, TXV was hunting all over the place and the evaporator outlet superheat was running low at times, figured this must be the low load they are talking about and how the TXV cant maintain superheat, because of the heat exchanger I still had superheat at my compressor so I just bumped up my box temperature a few degrees as an extra cushion so the load wasnt ' as low ', figured who needs ice cold beer in the winter time anyhow

    understanding ' why ' allowed me to adapt to that situation
    Exactly, that's why I wanted to get a better understanding of it.

  3. #29
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
    18,555
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    Quote Originally Posted by Olivero View Post
    Right, which makes sense. Kind of a way of idiot proofing it by giving you such a large margin of operation.

    I wasn't aware that the droplets were present or even presenting a problem, so I'm glad I now know that.

    Your signature made me laugh, a co worker and I actually did solder a relay onto a scotsman control board by soldering wires to the board so they were sticking out and then soldered the relay onto those wires, worked for months.
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

  4. #30
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    6,552
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    Quote Originally Posted by BBeerme View Post
    By Copeland saying they want no less than 20*F SH at the compressor, they are simply building in a huge safety margin. Nothing more, and nothing less.

    The reality is that you will see a wide variation between applications and temp ranges. For example, the older Manitowoc ice machines were dialed in at 1-2*F evap SH right before harvest. Don't know if they still do that.
    It is my understanding that ice machine compressors have beefier internal parts than low or med temp pumps
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  5. #31
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
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    If memory serves, ice machine compressors are medium temp.

    For what it is worth, compressors can handle those minute droplets of refrigerant entrained in the oil. Just think about a hot gas defrost, when the evap is actually being used as a condenser. As long as the oil in the compressor is plenty warm, then you're good to go.



    Quote Originally Posted by 2sac View Post
    It is my understanding that ice machine compressors have beefier internal parts than low or med temp pumps
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

  6. #32
    Join Date
    Nov 2018
    Posts
    21
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    Where and when has Dick Wirz stated at 5*SH liquid refrigerant is present? I personally own a few tomes of his, and do not remember anything of the sort?

  7. #33
    Join Date
    Dec 2012
    Location
    columbus, OH
    Posts
    5,696
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    Ive seen oil sight glasses churning and boiling at 8 or better SH.


    Sent from my iPhone using Tapatalk

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