FREE EPA 608 Study Guide 2026

This free EPA 608 study guide covers everything the EPA Section 608 Technician Certification exam tests, organized to the exam’s four official sections — Core plus Type I, Type II, and Type III.^[1]

It’s interactive, not a wall of text: every module has built-in checkpoint quizzes, flashcards, and practice questions, so you learn by doing — not just reading.

Section 608 is part of the federal Clean Air Act. Everyone takes the Core section, then the type section(s) for the equipment they service — or all three for Universal certification. Read a module, test yourself at each checkpoint, then drill gaps with our free practice test and flashcards. This guide is a high-yield overview that maps the tested content — not a full HVAC textbook.

EPA 608 Exam Snapshot

The exam is built in sections, and which ones you take depends on the equipment you work on. Everyone takes Core; technicians then add the type(s) they need.^[1] Here is how the sections map to real-world equipment:

Each section has the same 25 questions and the same ~70% passing standard, but they are scored separately — you can pass one and fail another.^[1]

Module 1 · Core

Required of everyone, and the foundation for every type. The Core section tests the “why” behind the rules — ozone and climate science, the refrigerant phase-out, the Clean Air Act regulations, and the basics of recovery and safety that apply no matter what equipment you service.

1.1 Ozone, Climate & the Phase-Out

The whole program exists to protect the Ozone layer in the Stratosphere, which absorbs harmful ultraviolet radiation. When a stable CFC or HCFC refrigerant is released, it drifts up over years; UV light then frees a chlorine atom, and a single chlorine atom catalytically destroys thousands of ozone molecules.^[7]

Two numbers describe a refrigerant’s impact: Ozone depletion potential (ODP, relative to CFC-11) and Global warming potential (GWP, relative to carbon dioxide). A refrigerant can have zero ODP yet a high GWP — that is exactly the case for the HFC refrigerants now in wide use.^[8]

The Montreal Protocol (1987) set the phase-out schedule: CFCs first (U.S. production ended in 1996), then HCFCs (R-22 production and import ended January 1, 2020). Now the AIM Act is phasing down high-GWP HFCs for their climate impact, steering the industry toward low-GWP HFO refrigerants.^[6]

1.2 Regulations, Recovery & Safety

The single most important rule in Section 608: since 1995 it is illegal to knowingly vent refrigerant during service, maintenance, repair, or disposal. Only small, unavoidable de minimis releases during good-faith recovery are allowed, and the prohibition now extends to most HFC substitutes too.^[2]

Three terms are constantly confused — and constantly tested. To Recover is just to remove refrigerant into a container. To Recycle is to clean it on-site for reuse in the same owner’s equipment. To Reclaim is to reprocess it to like-new purity meeting the AHRI 700 standard and verify it — the only refrigerant that may be sold to a new owner.^[4]

Buying refrigerant is restricted: under the Section 608 sales restriction, regulated refrigerants may be sold only to certified technicians, and the restriction now covers most HFCs.^[9] Store recovered refrigerant in a DOT-approved Recovery cylinder (gray body, yellow top) and never fill it past 80% by weight, because liquid refrigerant expands as it warms.

Module 2 · Type I — Small Appliances

The most accessible certification — and the only one that may be taken at home. Type I covers small appliances: the factory-sealed units that hold a small charge, like household refrigerators and window air conditioners.

2.1 What Counts as a Small Appliance

The definition is exact: a small appliance is fully manufactured, charged, and Hermetically sealed at the factory with 5 pounds or less of refrigerant. Refrigerators, freezers, window AC units, packaged terminal units, dehumidifiers, water coolers, and vending machines all qualify.^[1]

The make-or-break test is the factory seal. A unit that was field-assembled and field-charged on site — like a split-system central AC — is never a small appliance, even if it holds less than 5 pounds.

2.2 Type I Recovery Requirements

With recovery equipment made after November 15, 1993, a technician must recover at least 90% of the charge when the compressor is operating, and at least 80% when the compressor is not operating. A running compressor helps push refrigerant out, so more can be recovered.^[3]

Small appliances are the only equipment where System-dependent recovery (passive recovery, using the appliance’s own compressor or pressure) is allowed. Larger equipment must use Self-contained recovery gear with its own compressor.

Module 3 · Type II — High-Pressure

The bread-and-butter of HVAC. Type II covers high-pressure and very high-pressure appliances — split-system AC, heat pumps, and supermarket refrigeration racks — and is the certification most field technicians need.

3.1 High-Pressure Refrigerants & Equipment

High-pressure refrigerants operate above atmospheric pressure at normal temperatures. The classic ones are R-22 (the legacy HCFC), R-410A (the high-pressure HFC that replaced it), and R-404A and R-407C in commercial refrigeration.^[1]

R-410A operates at much higher pressures than R-22, so gauges, hoses, and recovery equipment must be rated for it — you cannot safely service an R-410A system with R-22-rated tools. Pressure and temperature move together (the pressure-temperature relationship), which is how a technician uses a P/T chart to check charge and superheat.

3.2 Recovery Vacuum & Leak Repair

Type II recovery levels are set in inches of mercury vacuum and depend on the charge size. With post-November-15-1993 equipment, a system with a charge 200 lb or less is recovered to 0 in. Hg (atmospheric), and a charge over 200 lb to 10 in. Hg vacuum.^[3]

For appliances containing 50 pounds or more, owners must repair leaks when the annual Leak rate exceeds the threshold: 10% for comfort cooling, 20% for commercial refrigeration, and 30% for industrial process refrigeration. Repairs generally must be completed within 30 days and then verified.^[5] When dehydrating a system to remove moisture, technicians pull a deep vacuum of about 500 Microns measured with a micron gauge.

Module 4 · Type III — Low-Pressure

The specialty section. Type III covers low-pressure appliances — the big centrifugal chillers that run under a vacuum. They behave differently from everything else, which is why they get their own rules.

4.1 Low-Pressure Chillers & Vacuum

A low-pressure appliance uses a refrigerant that boils below atmospheric pressure, so the low side of the system runs under a vacuum at normal temperatures. The classic refrigerants are R-11 (the original) and R-123 (its HCFC replacement), with R-1233zd as a near-zero-GWP HFO option.^[1]

Because the low side is under a vacuum, the leak problem is reversed: air and moisture leak into the system rather than refrigerant leaking out. Type III recovery uses its own unit — 25 mm Hg absolutewith post-1993 equipment — a value measured from a perfect vacuum, not the same as Type II’s inches of mercury vacuum.^[3]

4.2 Purge Units & Safe Service

Air and other Noncondensables that leak into a low-pressure chiller raise condensing pressure and cut efficiency, so a Purge unit removes them while keeping the refrigerant. A purge unit running far more than usual signals an air leak that should be found and fixed. High-efficiency purge units are preferred because they release far less refrigerant per unit of air purged.^[1]

Low-pressure vessels are protected from over-pressure by a Rupture disc set around 15 psig. That is why leak-testing is done with dry nitrogen kept below the disc setting — never oxygen (which can form a combustible mixture with the system’s oil) and never above ~15 psig (which would burst the disc).

Module 5 · Universal & Exam Strategy

The last module ties the sections together: how Universal certification works, and the specific numbers that separate a pass from a fail.

5.1 Earning Universal Certification

Universal is not a separate exam. You earn it by passing Core plus all three type sections — Type I, II, and III. Each of the four sections is 25 questions and is scored independently at about a 70% pass standard, so you can pass some and retake others.^[1]

Most field technicians pursue Universal because it covers every equipment type, but you only legally need the type(s) matching the equipment you service. Core is mandatory for all of them. Certification is delivered by EPA-approved organizations and, once earned, never expires.

5.2 Numbers to Memorize

EPA 608 rewards memorizing a short list of exact figures. Lock these in and you’ll recognize most of the numeric questions instantly:

How to Use This EPA 608 Study Guide

This guide is built to be worked, not just read. The most efficient path to a pass:

• Master Core first. It’s required of everyone and underpins all three types — ozone science, the three R’s, and the venting rule.
• Study only the types you need. Type I for small appliances, Type II for high-pressure, Type III for chillers — or all three for Universal.
• Memorize the numbers. Use the “numbers to memorize” table — the exam leans hard on exact recovery levels and thresholds.
• Check off as you go. Use the Study Guide Contents to mark each section done; it raises your exam-readiness score.
• Take every checkpoint, then drill. Send weak sections into the flashcards and a practice test until each section’s score clears 70%.

EPA 608 Glossary

The high-yield Section 608 terms in one place — hover any dotted term in the guide, or flip the whole deck here as a self-grading flashcard set.

AHRI 700

The industry purity standard that reclaimed refrigerant must meet before it can be sold to a different owner.

AIM Act

The American Innovation and Manufacturing Act of 2020, which directs the EPA to phase down high-GWP HFC refrigerants.

CFC

Chlorofluorocarbon — an early refrigerant (e.g., R-12) with high ozone depletion potential; U.S. production ended in 1996.

Clean Air Act

The federal law that gives the EPA authority to regulate air pollution, including the ozone-protection rules in Section 608.

De minimis release

A small, unavoidable release of refrigerant during good-faith recovery, which is not treated as illegal venting.

Global warming potential

GWP — a measure of how much heat a gas traps over time, relative to carbon dioxide (set at 1.0).

HCFC

Hydrochlorofluorocarbon — a transitional refrigerant (e.g., R-22) with lower ODP than CFCs; production/import ended Jan 1, 2020.

Hermetically sealed

Factory-sealed so the refrigerant circuit is closed; a key part of the small-appliance definition.

HFC

Hydrofluorocarbon — a chlorine-free refrigerant (e.g., R-410A, R-134a) with zero ODP but high GWP, now being phased down.

HFO

Hydrofluoroolefin — a newer refrigerant (e.g., R-1234yf, R-1233zd) with zero ODP and very low GWP; often mildly flammable (A2L).

High-pressure appliance

Type II equipment using a refrigerant that operates above atmospheric pressure (e.g., R-22, R-410A, R-404A).

Inches of mercury (in. Hg)

A vacuum unit used for high-pressure (Type II) recovery levels; e.g., 10 in. Hg for charges over 200 lb.

Leak rate

The percentage of an appliance's full charge lost per year; repair is required above set thresholds on appliances with 50+ lb.

Low-pressure appliance

Type III equipment using a refrigerant that boils below atmospheric pressure, so the low side runs under a vacuum (e.g., R-11, R-123).

Microns

A fine vacuum unit (1 micron = 0.001 mm Hg) used when dehydrating a system; about 500 microns is a typical deep-vacuum target.

mm Hg absolute

A pressure measured from a perfect vacuum; low-pressure (Type III) recovery must reach 25 mm Hg absolute.

Montreal Protocol

The 1987 international treaty that set the schedule for phasing out ozone-depleting substances.

Noncondensables

Gases such as air and nitrogen that do not condense in the system; they raise condensing pressure and lower efficiency.

Ozone depletion potential

ODP — a measure of how much a substance harms stratospheric ozone, relative to CFC-11 (set at 1.0).

Ozone layer

A region of the stratosphere rich in ozone that absorbs most of the sun's harmful ultraviolet radiation.

Purge unit

A device on a low-pressure chiller that removes air and noncondensables while retaining the refrigerant.

Reclaim

To reprocess refrigerant to like-new purity meeting the AHRI 700 standard and verify it chemically; the only refrigerant that may be resold to a new owner.

Reclaimer

An EPA-certified facility that reprocesses used refrigerant to AHRI 700 purity for resale.

Recover

To remove refrigerant from an appliance and store it in an external container, without cleaning or testing it.

Recovery cylinder

A reusable DOT-approved container (gray body, yellow top) for storing recovered refrigerant; never fill past 80% by weight.

Recycle

To clean recovered refrigerant on-site (oil separation, filter-driers) for reuse in the same owner's equipment.

Rupture disc

A pressure-relief device on a low-pressure chiller (set around 15 psig) that protects the vessel from over-pressure.

Section 608

The part of the U.S. Clean Air Act that regulates the handling of refrigerants in stationary air-conditioning and refrigeration equipment, including technician certification.

Self-contained recovery

Active recovery equipment with its own compressor that can pull refrigerant from an appliance on its own.

Small appliance

A product fully manufactured, charged, and hermetically sealed at the factory with 5 lb or less of refrigerant.

Stratosphere

The atmospheric layer above the troposphere (roughly 10–50 km up) where the protective ozone layer resides.

System-dependent recovery

Passive recovery that uses the appliance's own compressor or pressure to push refrigerant out; allowed only on small appliances.

Universal certification

The credential earned by passing Core plus Type I, II, and III; it covers all equipment types.

Venting

Knowingly releasing refrigerant to the atmosphere; prohibited under Section 608 during service, repair, or disposal since 1995.

EPA 608 Study Guide FAQ

References

1. 1.U.S. Environmental Protection Agency. “Section 608 Technician Certification Requirements.” epa.gov. ↑
2. 2.U.S. Environmental Protection Agency. “Prohibitions Under Section 608.” epa.gov. ↑
3. 3.U.S. Environmental Protection Agency. “Refrigerant Recovery and Recycling Equipment Requirements.” epa.gov. ↑
4. 4.U.S. Environmental Protection Agency. “Stationary Refrigerant Reclamation.” epa.gov. ↑
5. 5.U.S. Environmental Protection Agency. “Refrigerant Leaks.” epa.gov. ↑
6. 6.U.S. Environmental Protection Agency. “Phaseout of Ozone-Depleting Substances.” epa.gov. ↑
7. 7.U.S. Environmental Protection Agency. “Basic Ozone Layer Science.” epa.gov. ↑
8. 8.U.S. Environmental Protection Agency. “Reduction of HFCs Under the AIM Act.” epa.gov. ↑
9. 9.U.S. Environmental Protection Agency. “Sales Restriction on Refrigerants.” epa.gov. ↑

Career Employer

Career Employer is the ultimate resource to help you get started working the job of your dreams. We cover topics from general career information, career searching, exam preparation with free study materials, career interviewing, and becoming successful in your career of choice.

Follow Us:

All Posts