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reach in box in a diner

You need to let us know the pressurers and suction and liquid line temps,plus box temp and air into the cond coil - not room temp-


  • ddenny
    ddenny Member Posts: 75
    reach in box in a diner

    I found a freon leak in the evaporator, could'nt fix it so I replaced it with the same sdize evaporator. turns out the evap is only 600 btus (not 6000). the freon was R12 and is now 409A. I set the cut in cut out to 35 cut in and 20 out but the box does'nt cool below 45 it runs constantly and the suction line ices up. I found out the compressor is 1/3 horse power. the tx valve in the old evap was 1/2 ton which is way oversized so I put a 1/8 ton in the new evap. the people just bought the diner so I don't know the history of the machine. why is'nt it working. how shoyuld I siz the parts. and what's the relationship between horsepower and tonnage? the box is 28" high 27" deep and 44" wide. thankyou
  • Empire_2
    Empire_2 Member Posts: 2,343

    What is this reach in being used for? 600BTU/HR? 1/3 hp aprox = 2330 BTU/Hr. It all depends on if it's med temp/lo temp and ref being used etc... Is this a 2 beer keg box? There are guy's here that can better answer your question better than I.....

    Mike T.
  • Empire_2
    Empire_2 Member Posts: 2,343
    Hi Techman

    This box sounds like a beer cooler...... Think of the size. That's why I was Q...600BTU/HR. Very small for even pies. I think with the 1/3 hp condensing unit and the smaller evap, the i/8th ton TXV is to small and is starving the evap. I am thinking along the lines of up sizing the txv.......What I would really like is the #'s of all the equipment that was installed. Then we can crunch the refrigeration cycle on a P/E chart.


    Mike T. :-)
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Add to that....

    Add the compressor inlet temperature to that list....
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    You are correct Mike

    The 0.0125 ton TXV is definitely undersized. Given that this box is likely a medium temperature bix, it is not being used to maintain temperature but, more likely, bring warmer product to temperature. When such is the case, the cooling requirment of the system is much higher than the design capacity of the system.

    Consider a 2-ton system. This system is rated at 2 tons when the indoor temperature is 75 degrees @ 50% relastive humidity and a 95 degree oujtside ambient temperature. What happens when the system is first turned on? The load on the system will be much higher than 2 tons.

  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    You gonna plot it out?

    SInce you're noq an expert on Pressure Enthalpy, are you going to plot this system out for us Randy?
  • Techman
    Techman Member Posts: 2,144

    That evap being rated for 600BTU's, I beleave the rating is based on a 10*F ,TD between evap temp and box temp,so a 20*F TD would give you 1200BTU's.A 40*F box with an evap temp of 20*F and you have 1200BTU's.Whats the comp mfgr? model #?
This discussion has been closed.


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