A technician uses recovery equipment manufactured after November 15, 1993 on an R-22 split system that normally holds less than 200 pounds of refrigerant. To what level must the appliance be evacuated during recovery?

解析

R-22 is a high-pressure refrigerant (40 CFR §82.152 lists it by name). Under §82.156 Table 1, a high-pressure appliance with a full charge under 200 pounds must be evacuated to 0 inches Hg (atmospheric) with recovery equipment made on or after November 15, 1993. (b) 10 inches Hg is the level for a high-pressure appliance of 200 pounds or more, or for a medium-pressure appliance such as R-134a under 200 pounds; (c) 15 inches Hg is only for medium-pressure appliances of 200 pounds or more; (d) 4 inches Hg belongs to pre-1993 recovery equipment.