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  1. #1
    Join Date
    Jan 2015
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    please help.. r404 medium temp problems

    Help...... R404 medium temp... Ambient 43 suction line temp 60 suction pressure 80 high side 225 OK so here it is I removed all of the refrigerant. Pulled And held a 500 micron vacuum began to charge the system low side pressure was at 75 high side pressure was at 210 the sight glass finally cleared at 250 and the low side pressure was at 80 suction line temperature was 60 degrees which gave me a super heat of 25 degrees subcooling with at 7 degrees the headmaster was bypassing a bit at this point as my ambien is 50 degrees I have a 96 degree liquid line temperature across the dryer and across the solenoid I also called the supply house and had the unit sized to the box and everything is sized correctly the box is sized correctly to the evaporators and the evaporators are sized correctly to the condensing unit condensing unit...high superheat high suction... 2txvs 2evaps 3oil traps one on each evap. And one on main line before it goes up to the compressor ... Can't see the txvs as they had product in front of the panels .... Hopefully tomorrow when I go back they're gone... I think the wrong valves are in there ... All was installed in 2011 by another company. Unit has never went below 45°f according to the manager. New owners want it down to 35°f any one ever run into this before... Any help is greatly appreciated

  2. #2
    Join Date
    May 2014
    Location
    Bay Area California
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    We'd probably need to know the model numbers of the evaps and condensing unit to really get anywhere.

    But there is one thing you might want to do to verify the compressor hasn't received too much damage. Do a pump down test, valve off the compressor and see how low it will pull down, don't leave it there very long. After that test, then carefully valve in the discharge and see how high of a head you can get. These numbers will tell you if you have any major problems with compressor capacity.

  3. #3
    Join Date
    Jan 2015
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    Quote Originally Posted by BBeerme View Post
    We'd probably need to know the model numbers of the evaps and condensing unit to really get anywhere.

    But there is one thing you might want to do to verify the compressor hasn't received too much damage. Do a pump down test, valve off the compressor and see how low it will pull down, don't leave it there very long. After that test, then carefully valve in the discharge and see how high of a head you can get. These numbers will tell you if you have any major problems with compressor capacity.
    I did the above it pumps down via soleniod ,low side rotoloc and liquid line roto loc. All pump down within a minute and hold (held for 10 minutes on each) hi side pressure test fans off head master bypasses at 210 up to 400 then trips hi limit. Comp original Copeland m# cs20k6e-tf5-255 condensing unit Russell m# rlh325m44-e x2evaps Russell m# adla-65-158-ae 12glass door outside dimensions 32'x8'4"x3'4"

  4. #4
    Join Date
    May 2014
    Location
    Bay Area California
    Posts
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    I had a walk in that was about 12 glass doors I changed the compressor on a couple of months ago. So it was deeper than your three feet, but it took a five horse compressor. I would begin by questioning the capacity of the unit. You said it was sized properly, but I would try another source besides the supply house.

    I'm sure there are some rules of thumb, but since all I do is service, I don't get into equipment sizing any more. Guess I'm getting spoiled; I just turn over something like that to my supervisor. Pretty sure he's got a cheat sheet, or just years of experience, that tells him what the equipment sizing should be.

    Maybe the supply house sized the equipment for the size of the box, and didn't take into consideration all of the doors with their lights and heaters.

  5. #5
    Join Date
    Sep 2002
    Location
    Virginia
    Posts
    3,481
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    Hmm

    I would pump her down , unbolt txv inlet and check screen for trash ( hopefully not soldered on )

    If its soldered on , I would adjust txv , screw it out 1 full turn , then crank her up and when reaches close to 40 in box ,check SH again . Im thinking it just needs a tweaking.

  6. #6
    Join Date
    Jan 2015
    Posts
    4
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    Hahahahah wow it ended up being r22 valves installed ...... I removed em put in 404 valves and she ran like a champ
    Thanks for the input.

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