Answer: At present, most domestic cold dryers use R22 as refrigerant. It is non-flammable, non-explosive, colorless, odorless, and low in toxicity, and is a safe refrigerant; R22's unit volume cooling capacity is nearly 50% greater than R12 and its substitute R134a; R22 is slightly soluble in lubricating oil, they are mutually soluble in the compressor crankcase and condenser, and separated in the evaporator.
R22 will produce acid in the presence of trace moisture, which will slowly corrode metals. Therefore, when filling the refrigerant and adding refrigeration oil, be careful not to let moisture enter the system.
