EPA 608 topics
Ordered by official blueprint weight (the United States Environmental Protection Agency, 40 CFR part 82 subpart F, appendix D, section d (test content)).
Core is 25 of the items on whichever Section 608 test you sit, and 25 of the 100 on Universal. Appendix D fixes its three areas: the environmental impact of CFCs, HCFCs and substitute refrigerants; laws and regulations; and the changing industry outlook. EPA's own topic list adds refrigerant identification, the three R definitions, recovery technique, dehydration evacuation, safety and cylinder handling, and shipping labels.
Type I certifies you to maintain, service or repair small appliances — units manufactured, charged and hermetically sealed in a factory with five pounds of refrigerant or less. Its 25 items concentrate on recovery: the 80 and 90 percent thresholds, the four inches of mercury alternative, passive recovery from a unit whose compressor has failed, and access valves. It is the only type that may be offered as a mail-in test.
Type II certifies work on medium-, high- and very high-pressure appliances other than small appliances, MVACs and MVAC-like appliances. Its 25 items are the densest on the exam: the Table 1 evacuation levels, which change with charge size and with whether the recovery machine predates 15 November 1993, the leak rate thresholds, major versus non-major repairs, and the prohibition on system-dependent equipment above 15 pounds.
Type III certifies work on low-pressure appliances — those using a refrigerant with a liquid-phase saturation pressure below 45 psia at 104 °F, such as R-11, R-123 and R-245fa. Low-pressure centrifugal chillers run under a vacuum, which inverts most of what Type II teaches: leaks draw air and moisture in rather than pushing refrigerant out, recovery is to 25 mm Hg absolute, and pressurising for a leak test is done with controlled heat first, with nitrogen only as the fallback.