Study guide
9.1 What Type II Covers: High-Pressure System Overview
EPA 608 Technician Certification Exam
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1 Introduction to EPA 608 Certification
1.1 What EPA 608 Is and Who Needs It 1.2 Exam Format, Scoring, and Administration 1.3 How to Study for EPA 608
2 Regulations and the Clean Air Act
2.1 Clean Air Act Overview 2.2 Penalties and Enforcement 2.3 Montreal Protocol and International Agreements 2.4 AIM Act and HFC Phasedown Schedule 2.5 SNAP Program and Refrigerant Transitions
3 Refrigerants and Ozone Science
3.1 The Science of Ozone Depletion (ODP and GWP) 3.2 Refrigerant Classification, ASHRAE Numbering, and Safety Groups 3.3 Common Refrigerants: Properties, Applications, and Phaseout Status 3.4 Refrigerant Blends: Glide, Fractionation, and Liquid Charging
4 The Refrigeration Cycle
4.1 The Basic Refrigeration Cycle 4.2 System Components in Detail 4.3 Heat Transfer and Pressure-Temperature Relationships
5 Refrigerant Safety and Handling
5.1 Refrigerant Hazards and Health Effects 5.2 Safe Handling Practices, PPE, and Cylinders 5.3 A2L (Mildly Flammable) Refrigerant Safety
6 Recovery, Recycling, and Reclaiming
6.1 The Three Rs: Recover, Recycle, Reclaim 6.2 Recovery Equipment Requirements 6.3 Required Levels of Evacuation 6.4 Refrigerant Sales Restrictions and Recordkeeping
7 Leak Detection and Repair
7.1 Leak Detection Methods 7.2 Leak Repair Requirements and Trigger Rates 7.3 Leak-Rate Calculation, Recordkeeping, and Reporting
8 Type I — Small Appliances
8.1 What Counts as a Small Appliance 8.2 Type I Recovery Requirements 8.3 Type I Procedures, Access Valves, and the Open-Book Exam
9 Type II — High-Pressure Appliances
9.1 What Type II Covers: High-Pressure System Overview 9.2 Type II Recovery Methods and Required Evacuation Levels 9.3 Leak Detection, the Repair Triggers, and Recordkeeping 9.4 The R-22 Phaseout, Retrofits, and the Move to Lower-GWP A2Ls
10 Type III — Low-Pressure Appliances
10.1 Low-Pressure System Fundamentals 10.2 Purge Units and Air Management 10.3 Type III Recovery and Procedures 10.4 Type III Leak Testing
11 10. Disposal, Shipping, and Compliance
11.1 Equipment Disposal Requirements 11.2 Refrigerant Shipping and Transport 11.3 Compliance Checklist and Best Practices
12 Final Review and Exam Strategy
12.1 High-Yield Core Section Review 12.2 Type I vs Type II vs Type III: Side-by-Side Review 12.3 How the Exam Works and Exam-Day Strategy
9.1 What Type II Covers: High-Pressure System Overview
Key Takeaways Explain This Topic AI
Type II certifies work on medium-, high-, and very-high-pressure appliances — the most common systems in the field (residential/commercial AC, heat pumps, supermarket racks)
EPA defines pressure category by the refrigerant's liquid-phase saturation pressure at 104 °F: low below 45 psia, medium 45–170 psia, high 170–355 psia, very high above 355 psia (or a critical temperature below 104 °F)
R-410A is a high-pressure refrigerant in EPA's classes, like R-22, but it runs about 60% higher (~201 psig vs ~121 psig at 70 degrees F)
Type II does NOT cover small appliances (Type I), motor vehicle AC (Section 609), or low-pressure chillers (Type III)
A2L replacements R-454B and R-32 are reshaping new equipment, but existing EPA 608 Type II certification still authorizes servicing them
Last updated: October 2026
What Type II Certification Authorizes
Type II certification authorizes a technician to service, maintain, repair, and dispose of medium-, high-, and very-high-pressure appliances — by far the largest slice of the HVAC/R field. If you work on central air conditioning, heat pumps, rooftop units, walk-in coolers, or a supermarket refrigeration rack, you need Type II. Because these systems are everywhere, the Type II section of the EPA Section 608 exam is the one most candidates spend the most time on, and the one whose rules you will use almost every working day.
The EPA categorizes appliances not by their size but by the pressure of the refrigerant they contain . The dividing line is the refrigerant's liquid-phase saturation pressure at 104 °F (40 CFR 82.152). A refrigerant with a higher saturation pressure exerts more pressure throughout the system, which is why it is classified as high- or very high-pressure.
How EPA Defines the Pressure Categories
Category Liquid saturation pressure at 104 °F EPA's example refrigerants Type / Section
Very high-pressure Above 355 psia, or critical temperature below 104 °F R-13, R-23, R-503, R-508A, R-508B Type II
- High-pressure 170 to 355 psia R-22, R-407A, R-407C, R-410A, R-502 Type II
- Medium-pressure 45 to 170 psia R-114, R-124, R-12, R-134a, R-500 Type II
- Low-pressure Below 45 psia R-11, R-123, R-113, R-245fa Type III
Notice that medium-pressure equipment (such as some R-134a chillers) is serviced under Type II , not a separate certification — there is no "Type medium." Only the low-pressure category (below 45 psia at 104 °F), where the evaporator typically operates in a vacuum, falls under Type III. The exam frequently tests this boundary, so anchor on EPA's definitions and its example refrigerants rather than on boiling points.
Equipment Covered by Type II
Type II authorizes work on the following stationary systems:
Residential and light commercial:
- Central air conditioning — split systems and packaged units
- Air-source and ground-source (geothermal) heat pumps
- Ductless mini-split and multi-split systems
(Packaged terminal air conditioners and heat pumps are named small appliances when factory-sealed with 5 lb or less — those fall under Type I)
Commercial and industrial:
- Rooftop units (RTUs) and self-contained packaged systems
- Supermarket refrigeration racks and remote condensing units
- Walk-in coolers and freezers with remote compressors
- Reach-in coolers and commercial ice machines that hold more than 5 lbs of refrigerant
- Transport refrigeration on trucks and trailers (the refrigeration unit, not the vehicle cab AC)
- What Type II Does NOT Cover
Small appliances (5 lbs or less, factory-charged and hermetically sealed) — these are Type I .
Motor vehicle air conditioning (MVAC) — covered by Section 609 , a separate certification entirely.
Low-pressure appliances (centrifugal chillers using R-11 or R-123) — these are Type III because they operate below atmospheric pressure.
Example: A technician is dispatched to a grocery store to repair a leaking R-404A multiplex refrigeration rack holding 320 lbs of refrigerant, then crosses the parking lot to recharge a 4-lb window air conditioner with R-410A, and finally services a 600-ton R-123 centrifugal chiller in the basement. The rack and any unit over 5 lbs require Type II ; the window unit (5 lbs or less, self-contained) is a Type I small appliance; and the low-pressure R-123 chiller requires Type III . A technician needs Universal certification to legally touch all three in one day.
Pressure Ranges and Why They Matter
The practical reason pressure category matters is that higher operating pressure changes how you recover, evacuate, and service the system. R-410A systems run at roughly 60% higher pressure than an older R-22 system, which means recovery machines, hoses, gauges, and recovery cylinders must all be rated for the higher pressure . Using R-22-era equipment on R-410A is both unsafe and a likely cause of equipment rupture.
R-410A vs. R-22 — The Core Comparison
- Property R-22 (HCFC) R-410A (HFC blend)
- Pressure at 70 degrees F ~121 psig ~201 psig
- Relative operating pressure Baseline ~60% higher than R-22
- ODP 0.055 0
- GWP (100-yr) 1,810 2,088
- Lubricant Mineral oil or alkylbenzene POE (polyolester)
- ASHRAE safety class A1 A1
- Production status No new production since Jan 1, 2020 Restricted in new equipment (GWP cap of 700)
- Preferred charging method Liquid or vapor Liquid (per manufacturer guidance)
For the Exam: R-410A operates at roughly 60% higher pressure than R-22. You may not assume R-22 recovery equipment is rated for R-410A — verify the pressure rating. R-410A systems use hygroscopic POE oil , so minimize the time the system is open to atmosphere. Both are A1 (lower toxicity, non-flammable), but the newer A2L replacements (R-454B, R-32) are mildly flammable and require updated handling.
The A2L Transition Within Type II
Under the AIM Act's Technology Transitions rule, new residential and light commercial AC and heat-pump systems using refrigerant with a GWP of 700 or more may not be installed from January 1, 2025 (unless all specified components were made or imported before that date; VRF systems follow from 2026), which phases R-410A (GWP 2,088) out of new systems. The replacements — R-454B (GWP 466) and R-32 (GWP 675) — are both A2L (lower toxicity, mildly flammable) and are serviced under Type II.
Critically, no new federal certification is required : an existing Type II or Universal credential authorizes A2L service. What changes is the safety procedure — charge limits, leak-detection sensors, and spark-source precautions per UL 60335-2-40. Recall too that existing R-410A and R-22 systems are not banned; they may be serviced, repaired, and recharged for their full service life.