EPA 608 Type II Study Guide
Type II certification covers high-pressure appliances. This is the section most working HVAC technicians need, because it applies to residential and commercial air conditioning and to most commercial refrigeration. Type II questions go deeper than Type I: they expect you to understand pressures, evacuation, leak repair rules, and the practical service steps that keep a high-pressure system running correctly.
Work through the Core study guide first. Type II builds on Core, and the two are tested together.
What Is a High-Pressure Appliance
A high-pressure appliance uses a refrigerant whose boiling point and operating pressures fall into the high-pressure range — refrigerants such as HCFC-22, R-410A, R-404A, R-407C, and R-134a. In practical terms, Type II covers split-system and packaged air conditioners, heat pumps, supermarket refrigeration racks, walk-in coolers, and similar equipment. It excludes the factory-sealed small appliances handled under Type I and the low-pressure chillers handled under Type III. If a question describes equipment that was charged on site and operates at pressures well above atmospheric, you are in Type II territory.
Recovery and Required Evacuation Levels
Before you open a high-pressure system for major service, you recover the refrigerant. How deep a vacuum you must pull during recovery depends on two things: the size of the appliance charge, and whether your recovery equipment was manufactured before or after the regulatory cutoff date. Newer, certified equipment is held to deeper recovery requirements than older equipment.
The general pattern to understand: larger appliances and newer recovery equipment require pulling a deeper vacuum (measured in inches of mercury) before the job is considered complete. Smaller charges may have a lower required level. Because the EPA's exact evacuation table has specific numbers tied to specific charge sizes and equipment dates, and because those values have been revised over the years, study the current EPA evacuation requirements table directly rather than memorizing a number from an old prep book. Know the concept — bigger system and newer equipment means deeper required vacuum — and verify the exact figures against current material.
Recover liquid first when practical. Pulling liquid moves refrigerant far faster than pulling vapor, and finishing in vapor mode lets you reach the required vacuum. Protect the recovery unit's compressor: avoid slugging it with liquid in a mode it is not designed for, and watch for overheating on long recoveries.
Leak Repair Rules
Leak repair is a heavily tested Type II topic. Appliances above a threshold charge size are subject to leak rate limits — and that threshold dropped from 50 pounds to 15 pounds as of January 1, 2026, so far more equipment is now covered. If such an appliance leaks faster than its allowed annual percentage, the owner is required to repair the leaks or follow an approved alternative such as retrofitting or retiring the equipment, within a set time frame, and then verify the repair.
The allowed annual leak rate depends on how the equipment is used: comfort cooling is the strictest at 10 percent, commercial refrigeration is 20 percent, and industrial process refrigeration is the most lenient at 30 percent. Leaks past the threshold are generally repaired within 30 days, and verification testing follows the repair. Because these rules were updated in 2026 and may change again, confirm current numbers in official material — our leak repair requirements guide covers them in full.
Charging and Service Practices
Type II questions test practical charging knowledge. Charge a blended (zeotropic) refrigerant such as R-410A or R-407C as a liquid, because removing vapor from a blend can change the proportion of its components — a problem called fractionation. To avoid slugging the compressor with liquid, charge blends into the low side through a metering device or throttle the liquid so it flashes to vapor before reaching the compressor.
Use the pressure-temperature (PT) relationship to check a system. For a given refrigerant, pressure corresponds to a saturation temperature, which is how you measure superheat and subcooling to confirm a correct charge. The app includes a PT chart and PT chart practice mode for exactly this reason.
Non-Condensables and Moisture
Air and moisture do not belong in a refrigeration system. Air is a non-condensable gas: it will not condense at normal operating conditions, so it collects in the condenser and raises head pressure, hurting efficiency and capacity. Moisture is worse — it can freeze at the metering device and block flow, and it combines with refrigerant and oil to form acids that corrode the system from the inside.
The defense is a proper deep vacuum, or evacuation, after any repair that opened the system. Pulling a deep vacuum boils off moisture and removes non-condensables before you recharge. A micron gauge tells you when the system is truly dry and tight, rather than guessing from a standard gauge.
Cylinder and Safety Reminders
The Core safety rules carry straight into Type II, and high-pressure work makes them more important. Never fill a recovery cylinder past 80 percent — high-pressure refrigerants build pressure quickly as temperature rises. Never mix refrigerants in a cylinder. Watch the cylinder weight as you recover, since high-pressure systems can hold a substantial charge. Wear eye and hand protection, keep flame away from charged systems and cylinders, and ventilate enclosed equipment rooms.
How to Study Type II
Type II rewards understanding over memorization. Use Type II study mode to get comfortable with the vocabulary, then move to smart practice so the app drills your weak areas. Spend extra time on leak repair, evacuation requirements, and the difference between charging vapor and liquid. When a question feels tricky, identify the appliance type and refrigerant first, then ask whether it is testing a safety rule, a legal requirement, or a service procedure.
When study mode feels solid, take a Type II practice exam, then use Review Missed to close the gaps before exam day.
Next Steps
After Type II, see the Type III guide for low-pressure appliances, or revisit the Type I guide for small appliances. The exam overview explains how all four sections combine into Universal certification.
Not affiliated with the EPA. For study practice only. EPA regulations change over time — always verify current rules, leak rate thresholds, and evacuation levels with official EPA materials and your testing provider.