Free study guide

EPA 608 Study Guide

The EPA 608 test is four sections of 25 questions: a Core that everyone takes, and Type I, Type II and Type III for the equipment you work on. Study the Core first, because every certification includes it and the Type sections apply its rules to particular equipment, then the type or types you need. This guide restates all 26 of the EPA's published test topics in plain words, says what to memorize in each section, and gives a plan for a single type or for Universal.

The topics are the EPA's, from its Section 608 test-topics page, which is linked under 'What to study from' at the end. The statements below summarize the points under each of the EPA's topic headings in our own words. The EPA does not say how many questions come from each topic, only that each section is one 25-question group.

The weights table shows each section as a quarter. That is the Universal test. If you are going for one type, the Core and your type are half each, and the other two sections are not your concern.

This is an independent guide. This site does not give the test and does not issue Section 608 certification; only an EPA-approved certifying organization does.

Where the points are

The share of the exam each part of the current outline carries. Where the weights differ, study time should follow them.

Domain	Weight	Tasks
CORECore	25%	10
T1Type I (Small Appliances)	25%	3
T2Type II (High- and Very High-Pressure)	25%	6
T3Type III (Low-Pressure)	25%	7

The EPA 608 outline, task by task

CORECore25%

Ten topics, and the base for everything else. They fall into three groups. The science: how chlorine from CFC and HCFC refrigerants destroys stratospheric ozone, and which common refrigerants are CFCs, HCFCs and HFCs. The law: the Clean Air Act and the Montreal Protocol, the phaseouts, the bans on venting, the Section 608 rules on equipment, sales and reclaimed refrigerant. And the practice: the refrigeration cycle, gauges, leak detection, recovery, dehydration, cylinder safety and shipping labels.

CORE.1Environmental impacts: how chlorine from CFC and HCFC refrigerants destroys stratospheric ozone, which common refrigerants are CFCs, HCFCs or HFCs, their relative ozone-depletion potential and atmospheric effects, and the evidence for and health and environmental effects of ozone depletion.
CORE.2Clean Air Act and Montreal Protocol: CFC and R-22 phaseout dates, the bans on venting during service and at disposal and on venting substitute refrigerants, the maximum Clean Air Act penalty, and the Montreal Protocol's role.
CORE.3Section 608 regulations: high- versus low-pressure refrigerants, system-dependent versus self-contained recovery equipment, which equipment the rule covers, third-party certification of recovery and recycling equipment, the purity standard for reclaimed refrigerant, the sales restriction and the venting prohibition.
CORE.4Substitute refrigerants and oils: why there are no drop-in replacements, which lubricants are compatible with which refrigerants, and how blends fractionate when they leak.
CORE.5Refrigeration: refrigerant state and pressure at each point of the cycle and where cooling takes place, gauge color codes, ranges and correct use, and leak detection.
CORE.6Three R definitions: tell recovering, recycling and reclaiming refrigerant apart.
CORE.7Recovery techniques: why refrigerants must not be mixed, and what affects recovery speed, such as ambient temperature, equipment size and hose length and diameter.
CORE.8Dehydration evacuation: why a system is evacuated at the end of service to remove air and moisture.
CORE.9Safety: hazards of refrigerant exposure, protective equipment, reusable recovery cylinders versus disposable cylinders, the danger of filling a cylinder beyond 80 percent, and leak testing with nitrogen through a regulator and relief valve rather than oxygen or compressed air.
CORE.10Shipping: the refrigerant identification and DOT classification labels required on refrigerant cylinders.

Where people lose points: The three Rs, which have fixed meanings. To recover is to remove refrigerant from an appliance and store it in an external container, without necessarily testing or processing it. To recycle is to clean it for reuse, usually by separating oil and passing it through filter-driers, without meeting the reclamation standard. To reclaim is to reprocess it to the purity specifications the regulation sets, which are based on AHRI Standard 700, and verify that by analysis. Questions describe one and offer the other two as options. The cylinder rules are the other set to know exactly: a recovery cylinder is refillable and a disposable cylinder is not, a cylinder is not filled beyond 80 percent, and a system is pressurized for leak testing with nitrogen through a regulator and relief valve, never with oxygen or compressed air.

T1Type I (Small Appliances)25%

Three topics: recovery requirements, recovery techniques and safety. Know what counts as a small appliance. Know the evacuation level required in each of four cases, set by whether the recovery equipment was made before or after November 15, 1993 and whether the appliance's compressor works. Know passive, or system-dependent, recovery with an operating compressor and with one that does not run.

T1.1Recovery requirements: what counts as a small appliance, and the evacuation levels required with a working or non-working compressor for recovery equipment made before versus after November 15, 1993.
T1.2Recovery techniques: using pressure and temperature to identify a refrigerant and detect noncondensables, passive (system-dependent) recovery with operating and inoperative compressors, fitting high- and low-side access valves, removing solderless fittings after service, and R-134a as the likely substitute for R-12.
T1.3Safety: the decomposition products formed when refrigerants are exposed to high temperatures.

Where people lose points: Taking the short topic list for a light section. Type I has three headings and the same 25 questions as every other section, so expect its few topics to be asked from several directions. The four-case recovery table is the place to be careful: it is easy to learn one figure and apply it to every case. The smaller points are easy marks if you have seen them: that both high-side and low-side access valves are needed when the compressor does not run, that solderless fittings come off after service, and what refrigerants break down into at high temperatures.

T2Type II (High- and Very High-Pressure)25%

Six topics, and the most rule-heavy section. Leak detection and the leak repair requirements: allowable leak rates for commercial refrigeration, industrial process refrigeration and other appliances holding more than 50 pounds, with the recordkeeping and deadline extensions that go with them. Recovery techniques and the evacuation levels required in each situation. The refrigeration topic: identifying the refrigerant, pressure-temperature relationships, and what state the refrigerant is in at each component. And safety, including equipment room requirements.

T2.1Leak detection: signs of leakage in high-pressure systems, leak testing before charging or recharging, and the order of preference for leak-test gases.
T2.2Leak repair requirements: allowable leak rates for commercial and industrial process refrigeration and for other appliances holding more than 50 pounds, leak repair recordkeeping, and extensions to repair deadlines.
T2.3Recovery techniques: speeding recovery by removing liquid first, chilling the recovery vessel or heating the appliance, avoiding cross-contamination when a machine changes refrigerants, and waiting after reaching the required vacuum to see whether pressure rises.
T2.4Recovery requirements: evacuation levels for high-pressure appliances by situation (disposal, major versus non-major repair, leaky versus non-leaky, under versus over 200 pounds, equipment built before versus after November 15, 1993), what a major repair is, and the ban on system-dependent equipment above 15 pounds of refrigerant.
T2.5Refrigeration: identifying the refrigerant in an appliance, pressure-temperature relationships of common high-pressure refrigerants including gauge-to-absolute conversion, components of high-pressure appliances and the refrigerant state in each, and the rule that hydrocarbons are not approved for retrofits.
T2.6Safety: never energizing a hermetic compressor under vacuum, and ASHRAE Standard 15 equipment room requirements, including oxygen deprivation sensors.

Where people lose points: The evacuation-level table has five variables: disposal or repair, major or non-major repair, leaky or not, under or over 200 pounds of refrigerant, and recovery equipment built before or after November 15, 1993. Write the table out yourself until you can do it from memory. Keep the leak-rate thresholds attached to the right category of appliance, because the options will offer the right number for the wrong category. Three single facts from the topics are worth having cold: system-dependent recovery equipment is not allowed on appliances holding more than 15 pounds, a hermetic compressor must never be energized under vacuum, and gauge pressure becomes absolute pressure by adding atmospheric pressure.

T3Type III (Low-Pressure)25%

Seven topics built on one physical fact: parts of a low-pressure system run below atmospheric pressure, so a leak draws air and moisture in instead of letting refrigerant out. That is why these systems have purge units, why excessive purging is a sign of a leak, and why leak testing means raising the system's pressure, with hot water or built-in heating first and nitrogen after. The rest follows: leak repair requirements, recovery and recharging techniques that keep water in the tubes from freezing, evacuation levels, and equipment room safety including a refrigerant sensor for R-123.

T3.1Leak detection: preferred ways to pressurize a low-pressure system for leak testing (hot water or built-in heating, then nitrogen), signs of air leaking in such as excessive purging, the maximum leak-test pressure for centrifugal chillers, leak inspections for appliances over the leak rate, and reporting of chronically leaking appliances.
T3.2Leak repair requirements: allowable annual leak rates for commercial and industrial process refrigeration and for other appliances holding more than 50 pounds.
T3.3Recovery techniques: recovering liquid first and then vapor, heating oil to 130 degrees F before draining it, circulating or removing chiller water to prevent freezing during evacuation, and the high-pressure cut-out setting of recovery units used on low-pressure appliances.
T3.4Recharging techniques: introducing vapor before liquid so water in the tubes does not freeze, and charging centrifugal chillers through the evaporator charging valve.
T3.5Recovery requirements: evacuation levels for low-pressure appliances by situation (disposal, major versus non-major repair, leaky versus non-leaky, under versus over 200 pounds, equipment built before versus after November 15, 1993), what major and non-major repairs are, permitted ways to pressurize for a non-major repair, and waiting after reaching vacuum to check for a pressure rise.
T3.6Refrigeration: what a purge unit does in a low-pressure system, and pressure-temperature relationships of low-pressure refrigerants.
T3.7Safety: ASHRAE Standard 15 equipment room requirements, including oxygen deprivation sensors and a refrigerant sensor for R-123.

Where people lose points: Carrying Type II habits into Type III. The orders are the thing to learn. Recovering: liquid first, then vapor. Recharging: vapor first, then liquid, so that water in the tubes does not freeze. During evacuation, circulate or remove the chiller water for the same reason. Oil is heated to 130 degrees F before it is drained. The EPA lists the same situations for low-pressure evacuation levels as for Type II, but the required values are different, and a Universal candidate who has learned both in the same week can easily swap them.

A study plan

Before you start: choose the certification and call the organization
Decide between a single type and Universal, then ask your certifying organization for its time limit, its fee and how it scores each section. Take the free 25-question diagnostic, which samples all four sections; read only the sections you will sit.
Week 1: the Core
Take the ten topics in three passes: the science and the law first, then the Section 608 rules and the three Rs, then the practical topics from the refrigeration cycle to shipping. Start a numbers sheet on day one and add every date, weight and percentage to it with the rule it belongs to.
Week 2: your type, or Type II if you are going for Universal
For a single type, this week is that section, finished with a timed run of 50 questions: the Core and your type. For Universal, do Type II now. It has the largest set of rules, and Type III is easier to learn as a contrast to it.
Week 3, Universal only: Type III, then Type I
Learn Type III beside your Type II notes and write the two evacuation tables on one page so the differences are visible. Type I takes a day or two at the end. Do not skip it because it looks short.
The last days: sections as blocks
Practice each section as a timed block of 25, then all of your sections back to back. A full Universal mock on this site is 100 questions in 2 hours; that time is our own convention, about half an hour a section, and not a limit set by the EPA. Use the limit your organization gave you if it is different.

The free EPA 608 diagnostic is being prepared and is not open yet. The exam facts and the content outline on this page are current.

Build a numbers sheet, from the current rule

More than most trade tests, this one asks for specific figures: a date that splits recovery equipment into two groups, weights of refrigerant that change which rule applies, a fill limit, a temperature, evacuation levels, leak rates. They are easier to keep when each is written beside the rule it belongs to and the reason for the rule, which is how the explanations on this site present them.

Take every figure on your sheet from the current regulation, 40 CFR Part 82 Subpart F, or from material you know has been checked against it. The EPA's test-topics page still carries some older details, and the regulation now applies some requirements, such as the venting prohibition, to substitute refrigerants like HFCs as well. A figure memorized from an old handout is the most avoidable way to lose a question.

Prepare each section to stand alone

The passing score is 70 percent, and certifying organizations generally apply it to each 25-question section, which is 18 correct. We could not confirm that reading in the EPA's own wording, so check it with your organization. Either way the safe preparation is the same: bring every section you are sitting above the line, and do not count on the Core to make up for a weak Type section.

How long to study

The EPA sets no study period and no prerequisite. For someone already working around this equipment, two weeks is a realistic plan for the Core and one type, and three for Universal. If the vocabulary is new to you, give the Core a second week before moving on; the Type sections assume it.

If you are considering the open-book Type I test

Type I alone may be taken open-book by mail, with a passing score of 84 percent in place of 70. Universal certification needs the Core taken as a proctored closed-book test, so the open-book route does not shorten the way to Universal. If you expect to work on anything larger than small appliances, study for the proctored test.

What to study from

Section 608 Technician Certification Test Topics (U.S. EPA)
40 CFR Part 82, Subpart F - Recycling and Emissions Reduction The governing regulation, including Appendix D, Standards for Becoming a Certifying Program for Technicians.
Clean Air Act, Title VI, Section 608 (42 U.S.C. 7671g) - National Recycling and Emission Reduction Program
Section 608 Technician Certification Requirements (U.S. EPA)
EPA's Refrigerant Management Program: Questions and Answers for Section 608 Certified Technicians (U.S. EPA)
AHRI Standard 700 - Specifications for Refrigerants The purity standard for reclaimed refrigerant named in the test topics.
ANSI/ASHRAE Standard 15 - Safety Standard for Refrigeration Systems Equipment room requirements named in the Type II and Type III topics.
Montreal Protocol on Substances that Deplete the Ozone Layer

These are the sources the questions in the bank cite. The outline in force is the EPA Section 608 Technician Certification Test Topics (web page last updated December 5, 2025).

EPA 608 study guide: common questions

Is this EPA 608 study guide free?

Yes. This page is free, and so is the 25-question diagnostic, which needs no account. The paid pass adds the full question bank and timed mock exams. The questions are original and are not taken from the EPA test bank.

Does the EPA publish an official 608 study guide?

The EPA publishes the test topics for each section and the regulation they are drawn from; both are linked in the references on this page. Your certifying organization may have preparation material of its own, so ask when you register.

What should I study first for the EPA 608 test?

The Core. Every certification includes it, and Type I, II and III apply its rules on recovery, venting and safety to particular kinds of equipment.

What is on the EPA 608 Core section?

Ten topics: environmental impacts, the Clean Air Act and Montreal Protocol, the Section 608 regulations, substitute refrigerants and oils, refrigeration, the definitions of recover, recycle and reclaim, recovery techniques, dehydration evacuation, safety and shipping.

Do I need to study all four sections?

Only for Universal. For Type I, II or III on its own you study the Core and that one section, 50 questions in all.

How long does it take to study for the EPA 608?

There is no required period. About two weeks for the Core and one type, or three for Universal, is workable for someone who already handles the equipment. Allow more if the terms are new.

EPA Section 608 Technician Certification is a federal certification established under the Clean Air Act and overseen by the U.S. Environmental Protection Agency (EPA). This site is an independent study resource; it is not affiliated with, endorsed by, or approved by the EPA or by any EPA-approved certifying organization, and it does not issue Section 608 certification. Practice questions here are original and are not taken from the EPA test bank.