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  1. #14
    Join Date
    Dec 2008
    Location
    NW Iowa
    Posts
    121
    I would normally use the med. temp lenght for a cooler running this temp. Is that right? I thought the high temp. was for A/C or a cooler that ran 50 or above.

  2. #15
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,244
    Interesting experiment. I don't think most people would have the balls to change refrigerants like you did, it's good to think outside of the box sometimes.

    A few things that I am curious about, though... I know that some compressors are designed differently for different refrigerants and applications. There might be a bunch of compressors that have a 1/3 hp motor, but they might have a different piston and/or crank size depending on what refrigerant and/or temperature they will be running. Did you do any checking to see if your compressor was rated for high/medium temp with R134a? If it is rated for low temp only, you might be causing problems by running it with such a warm suction temperature, since it is designed to be cooled by the refrigerant.

    How warm was the compressor shell? How was your amp draw? Did you keep the defrost heaters and/or fan delay? Did you warn the customer that this was an experiment and that the compressor might not last long?

  3. #16
    Join Date
    Jul 2011
    Location
    Lehigh Valley, PA
    Posts
    427
    Ammoniadog. I am the in-house & only service tech for a company in which owns 30 P Huts. I am the boss, the parts man, and service tech of my one man department. The unit is useless to us at this location as a freezer. And it was about 10 yrs old & original compressor. Someone opened it up once about a yr ago, installed taps & a Sporlan dryer but didn't change the cap tube. This puzzles me.

    The unit ran much warmer with R404. A previous refrg tech company to me actually wired the condenser fan to run continuous. I wired it back to normal operation. The compressor was running much cooler yesterday, the head of the compressor was at best warm temp. I did not bother checking amp draw with so low head psi. And I didn't actually check R404 vs R134 but I have seen many small compressors of this size in some of my equipment with a label showing R134/R404. Is this really a concern with fractual compressors with POE? And my compressor ratio hasn't really changed. My biggest concern is with the low suction, I was hoping to see closer to 20psi which may actually happen come summer when the kitchen heats up. I'll check on it later in the week and run it thru a defrost to monitor box temps. But I don't see an issue with the electric heaters, All of my Traulsen VPS120's Make/Prep Tables all have electric defrost with fan delays.

  4. #17
    Join Date
    Aug 2009
    Location
    Maine
    Posts
    3,054
    Quote Originally Posted by trippintl0 View Post
    I guess my way of looking at it is, the potential downside of NOT having defrost, is a possible freeze-up. The potential downside of leaving defrost intact: Nothing. Plenty of walk-in-coolers are set-up for electric defrost, and some Traulsen coolers even use electric defrost.
    You don't want to run the heaters in a cooler. Plus you have to have the fans wired to run full time. The fans are the coolers defrost.

  5. #18
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,244
    Quote Originally Posted by lytning View Post
    You don't want to run the heaters in a cooler. Plus you have to have the fans wired to run full time. The fans are the coolers defrost.
    Re-read the last sentence of the part that you quoted above.

    I agree with you that heaters aren't needed in most coolers, and especially in this situation, however they are used sometimes. Some coolers do use the same type of defrost cycle as a freezer. Usually ones designed for high humidity (like a retarder) or for maintaining temperatures close to, or slightly below 32 degrees (like a beer cooler). In these situations, the fans do shut off during defrost and they usually have a fan delay afterwords.

  6. #19
    Join Date
    Aug 2009
    Location
    Maine
    Posts
    3,054
    I will go along with the retarders. Aren't sure if below 32 degrees is a cooler or not. In any case there are exceptions to everything, along with special applications.

  7. #20
    Join Date
    Jul 2011
    Location
    Lehigh Valley, PA
    Posts
    427
    Quote Originally Posted by lytning View Post
    You don't want to run the heaters in a cooler. Plus you have to have the fans wired to run full time. The fans are the coolers defrost.
    All of the Traulsen prep tables I see running R404A use electric defrost. Temps in the coil drop to about 12F and the doors are opened often in a busy kitchen. In fact, I was thinking what you wrote above, I eliminated the defrost cycles on a unit last summer in an attempt to have better cooling. I was back two days later with iced evaps. I felt just a little bad...

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