We just replaced a R12 refrigerator system with a R22 condensing unit.We were told to replace the expansion valve and we did the usual drier replacement and evac and so on. This was not a burn out.The system had a leak so we replaced the condensor to r22. Its water cooled with a water reg valve, pump down via solenoid by stat.
Unit is 3/4 hp and was charged to clear sight glass. Reg valve set to 210LBS. This is a refrig, not freezer.The problem, the evap freezes up at the bottom, about 1/3 of the way up.So only the upper 2/3 passes air through coil.