I have a customer with a reach in ice cream freezer, the type with a glass cover with the tubs of ice cream where you can go look and see what kind you want. Its an old kelvinator, semi hermitic compressor, r-22. Originally I found the unit tripping on high pressure due to a completely plugged condenser, this condenser has no fins just copper tubing looped back and forth about an inch apart with a fan pulling air through the coil and pushing it over the compressor. I cleaned the condenser, the unit would run but the pressures were off, and still tripped the high pressure switch intermittently. By the look of the pressures I thought it had a plugged liquid dryer or a blocked cap tube. I pulled the charge, replaced the dryer, which seemed clean, blew nitrogen through both ways and no blockage and nothing came out. Purged nitrogen through the high and low sides and all seemed clear. Evacuated to 340 microns, pumped the charge back in, and now the cooler is working fine, about 200 discharge, but only 0-2# suction pressure with about an 80 degree suction line. The box started at about 75 and with in a half hour was down to about 18 and still running. There is no evap fan so I understand the suction will be low but the pressures and superheat still look off to me, the cooler is working fine now, but I am a little confused on what superheat and subcooling to look for, and it seems as though this compressor would need cooler suction temps to keep it cool, the fan is blowing air over it, but something just doesnt make sense.