EPA 608 study guide, section by section

EPA publishes the topics its Section 608 tests cover, in four lists: Core, Type 1, Type 2 and Type 3. [EPA test topics] This page sets them out in EPA’s own words, with the section of the regulation to read for each. We added no topics and no figures of our own.

Universal is for servicing all types of equipment. [EPA certification requirements] The test structure page has the question counts.

Core

EPA’s list for Core. [EPA test topics]

Environmental Impacts

Destruction of ozone by chlorine
Presence of chlorine in chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerants
Identification of CFC, HCFC, and hydrofluorocarbon (HFC) refrigerants (not chemical formulas, but idea that R-12 is a CFC, R-22 is an HCFC, R-134 is an HFC, etc.)
Idea that CFCs have higher ozone-depletion potential (ODP) than HCFCs, which in turn have higher ODP than HFCs
Understanding of the atmospheric effects from the types of refrigerants
Health and environmental effects of stratospheric ozone depletion
Evidence of stratospheric ozone depletion and role of CFCs and HCFCs

Clean Air Act and Montreal Protocol

CFC phaseout date
R-22 phaseout date
Venting prohibition at servicing
Venting prohibition at disposal
Venting prohibition on substitute refrigerants
Maximum penalty under the Clean Air Act
Montreal Protocol (the international agreement to phase out production of ozone-depleting substances)

Section 608 Regulations

Definition/identification of high and low-pressure refrigerants
Definition of system-dependent versus self-contained recovery/recycling equipment
Identification of equipment covered by the rule (all air-conditioning and refrigeration equipment containing CFCs or HCFCs except motor vehicle air conditioners)
Need for third-party certification of recycling and recovery equipment
Standard for reclaimed refrigerant [Air Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 700-2016]
The sales restriction
The Clean Air Act prohibition on venting

Substitute Refrigerants and oils

Absence of "drop-in" replacements
Incompatibility of substitute refrigerants with many lubricants used with CFC and HCFC refrigerants and incompatibility of CFC and HCFC refrigerants with many new lubricants (includes identification of lubricants for given refrigerants, such as esters with R-134; alkylbenzenes for HCFCs)
Fractionation problem--tendency of different components of blends to leak at different rates

Refrigeration

Refrigerant states (vapor versus liquid) and pressures at different points of refrigeration cycle; how/when cooling occurs
Refrigeration gauges (color codes, ranges of different types, proper use)

Leak Detection

EPA lists no topics under this heading.

Three R Definitions

Recover
Recycle
Reclaim

Recovery Techniques

Need to avoid mixing refrigerants
Factors affecting speed of recovery (ambient temperature, size of recycling or recovery equipment, hose length and diameter, etc.)

Dehydration Evacuation

Need to evacuate system to eliminate air and moisture at the end of service

Safety

Risks of exposure to refrigerant (e.g., oxygen deprivation, cardiac effects, frost bite, long-term hazards)
Personal protective equipment [gloves, goggles, self-contained breathing apparatus (SCBA)-in extreme cases, etc.]
Reusable (or "recovery") cylinders versus disposable cylinders [ensure former Department of Transportation (DOT) approved, know former's yellow and gray color code, never refill latter]
Risks of filling cylinders more than 80 percent full
Use of nitrogen rather than oxygen or compressed air for leak detection
Use of pressure regulator and relief valve with nitrogen

Shipping

Labels required for refrigerant cylinders (refrigerant identification, DOT classification tag)

Read in the regulation

§ 82.152 Definitions: the pressure classes, recover and reclaim, system-dependent and self-contained recovery equipment. [40 CFR 82.152]
§ 82.154 Prohibitions: the venting prohibition and the sales restriction. [40 CFR 82.154]
§ 82.158 Standards for recovery and/or recycling equipment: the equipment standards. [40 CFR 82.158]

Type 1 (Small Appliances)

EPA’s list for Type 1 (Small Appliances). [EPA test topics]

Recovery Requirements

Definition of "small appliance"
Evacuation requirements for small appliances with and without working compressors using recovery equipment manufactured before November 15, 1993
Evacuation requirements for small appliances with and without working compressors using recovery equipment manufactured after November 15, 1993

Recovery Techniques

Use of pressure and temperature to identify refrigerants and detect noncondensables
Methods to recover refrigerant from small appliances with inoperative compressors using a system-dependent or "passive" recovery device (e.g., heat and sharply strike the compressor, use a vacuum pump with non-pressurized recovery container)
Need to install both high and low side access valves when recovering refrigerant from small appliances with inoperative compressors
Need to operate operative compressors when recovering refrigerant with a system-dependent ("passive") recovery device
Should remove solderless access fittings at conclusion of service
Hydrofluorocarbon (HFC)-134a (also called R-134a) as likely substitute for chlorofluorocarbon (CFC)-12 (also called R-12)

Safety

Decomposition products of refrigerants at high temperatures

Read in the regulation

§ 82.152 Definitions: the definition of a small appliance. [40 CFR 82.152]
§ 82.156 Proper evacuation of refrigerant from appliances: evacuation requirements. [40 CFR 82.156]
§ 82.155 Safe disposal of appliances: disposal. [40 CFR 82.155]

Type 2 (High-Pressure)

EPA’s list for Type 2 (High-Pressure). [EPA test topics]

Leak Detection

Signs of leakage in high-pressure systems (excessive superheat, traces of oil for hermetics)
Need to leak test before charging or recharging equipment
Order of preference for leak test gases [nitrogen alone best, but nitrogen with trace quantity of hydrochlorofluorocarbon (HCFC)-22 (also called R-22) better than pure refrigerant]

Leak repair requirements

Allowable leak rate for commercial and industrial process refrigeration
Allowable leak rate for other appliances containing more than 50 pounds of refrigerant
Leak repair recordkeeping
Extensions to the timeframe to repair leaks that exceed the threshold leak rate

Recovery Techniques

Recovering liquid at beginning of recovery process speeds up process
Other methods for speeding recovery (chilling recovery vessel, heating appliance or vessel from which refrigerant is being recovered)
Methods for reducing cross-contamination and emissions when recovery or recycling machine is used with a new refrigerant
Need to wait a few minutes after reaching required recovery vacuum to see if system pressure rises (indicating that there is still liquid refrigerant in the system or in the oil)

Recovery Requirements

Evacuation requirements for high-pressure appliances in each of the following situations:
- Disposal
- Major versus non-major repairs
- Leaky versus non-leaky appliances
- Appliance (or component) containing less versus more than 200 pounds
- Recovery/recycling equipment built before versus after November 15, 1993
Definition of "major" repairs
Prohibition on using system-dependent recovery equipment on systems containing more than 15 pounds of refrigerant

Refrigeration

How to identify refrigerant in appliances
Pressure-temperature relationships of common high-pressure refrigerants [may use standard temperature-pressure chart--be aware of need to add 14.7 to translate pounds per square inch gauge (psig) to pounds per square inch absolute (psia)]
Components of high-pressure appliances (receiver, evaporator, accumulator, etc.) and state of refrigerant (vapor versus liquid) in them
The idea that hydrocarbons are not approved for retrofits

Safety

Shouldn't energize hermetic compressors under vacuum
Equipment room requirements under American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard 15 (oxygen deprivation sensor with all refrigerants)

Read in the regulation

§ 82.156 Proper evacuation of refrigerant from appliances: evacuation requirements. [40 CFR 82.156]
§ 82.157 Appliance maintenance and leak repair: leak repair for appliances holding 50 or more pounds of a CFC or HCFC (class I or class II) refrigerant. [40 CFR 82.157]
40 CFR 84.106 Leak repair: since January 1, 2026, leak repair for many appliances holding 15 or more pounds of an HFC or other substitute refrigerant, with exceptions such as residential and light commercial air conditioning and heat pumps; read it with § 82.157, because which one applies depends on the refrigerant. [40 CFR 84.106]
§ 82.152 Definitions: high-pressure appliances. [40 CFR 82.152]

Type 3 (Low-pressure)

EPA’s list for Type 3 (Low-pressure). [EPA test topics]

Leak Detection

Order of preference of leak test pressurization methods for low-pressure systems
- Hot water method or built-in system heating/pressurization device such Prevac
- Nitrogen
Signs of leakage into a low-pressure system (e.g., excessive purging)
Maximum leak test pressure for low-pressure centrifugal chillers
Leak inspection requirements for appliances that exceed the leak rate
Reporting for chronically leaking appliances

Leak repair requirements

Allowable annual leak rate for commercial and industrial process refrigeration
Allowable annual leak rate for other appliances containing more than 50 pounds of refrigerant

Recovery Techniques

Recovering liquid at beginning of recovery process speeds up process
Need to recover vapor in addition to liquid
Need to heat oil to 130°F before removing it to minimize refrigerant release
Need to circulate or remove water from chiller during refrigerant evacuation to prevent freezing
High-pressure cut-out level of recovery devices used with low-pressure appliances

Recharging Techniques

Need to introduce vapor before liquid to prevent freezing of water in the tubes
Need to charge centrifugals through evaporator charging valve

Recovery Requirements

Evacuation requirements for low-pressure appliances in each of the following situations:
- Disposal
- Major versus non-major repairs
- Leaky versus non-leaky appliances
- Appliance (or component) containing less versus more than 200 pounds
- Recovery/recycling equipment built before versus after November 15, 1993
Definitions of "major" and "non-major" repairs
Allowable methods for pressurizing a low-pressure system for a non-major repair (controlled hot water and system heating/pressurization device such as Prevac)
Need to wait a few minutes after reaching required recovery vacuum to see if system pressure rises (indicating that there is still liquid refrigerant in the system or in the oil)

Refrigeration

Purpose of purge unit in low-pressure systems
Pressure-temperature relationships of low-pressure refrigerants

Safety

Equipment room requirements under ASHRAE Standard 15 (oxygen deprivation sensor with all refrigerants)
Under ASHRAE Standard 15, need to have equipment room refrigerant sensor for R-123

Read in the regulation

§ 82.156 Proper evacuation of refrigerant from appliances: evacuation requirements. [40 CFR 82.156]
§ 82.157 Appliance maintenance and leak repair: leak repair for appliances holding 50 or more pounds of a CFC or HCFC (class I or class II) refrigerant. [40 CFR 82.157]
40 CFR 84.106 Leak repair: since January 1, 2026, leak repair for many appliances holding 15 or more pounds of an HFC or other substitute refrigerant, with exceptions such as residential and light commercial air conditioning and heat pumps; read it with § 82.157, because which one applies depends on the refrigerant. [40 CFR 84.106]
§ 82.152 Definitions: low-pressure appliances. [40 CFR 82.152]

The pressure classes, as the regulation defines them

The Core list asks for the “Definition/identification of high and low-pressure refrigerants.” [EPA test topics] 40 CFR 82.152 defines each class by the refrigerant’s pressure at 104 °F, and lists examples that are “not limited to” these. [40 CFR 82.152]

Appliance	Uses	Examples (appliances using)
Low-pressure	a refrigerant with a liquid phase saturation pressure below 45 psia at 104 °F	R-11, R-123, R-113, and R-245fa
Medium-pressure	a refrigerant with a liquid phase saturation pressure between 45 psia and 170 psia at 104 °F	R-114, R-124, R-12, R-134a, and R-500
High-pressure	a refrigerant with a liquid phase saturation pressure between 170 psia and 355 psia at 104 °F	R-22, R-407A, R-407C, R-410A, and R-502
Very high-pressure	a refrigerant with a critical temperature below 104 °F or with a liquid phase saturation pressure above 355 psia at 104 °F	R-13, R-23, R-503, R-508A, and R-508B

Small appliance

The Type 1 list starts with the definition of “small appliance.” [EPA test topics] The regulation: “any appliance that is fully manufactured, charged, and hermetically sealed in a factory with five (5) pounds or less of refrigerant,” including refrigerators and freezers, room air conditioners, dehumidifiers, under-the-counter ice makers, vending machines, and drinking water coolers. [40 CFR 82.152]

Numbers that appear in EPA’s list

These are the figures EPA’s topic list names. The list names the topic, not the answer, so read the regulation for the values. [EPA test topics]

Number	EPA’s line	Where
80 percent	Risks of filling cylinders more than 80 percent full	Core, Safety
November 15, 1993	Evacuation requirements for small appliances with and without working compressors using recovery equipment manufactured before November 15, 1993	Type 1, Recovery Requirements (also in Type 2 and Type 3)
200 pounds	Appliance (or component) containing less versus more than 200 pounds	Type 2 and Type 3, Recovery Requirements
15 pounds	Prohibition on using system-dependent recovery equipment on systems containing more than 15 pounds of refrigerant	Type 2, Recovery Requirements
50 pounds	Allowable leak rate for other appliances containing more than 50 pounds of refrigerant	Type 2 (Type 3 has the annual version), Leak repair requirements
14.7	Pressure-temperature relationships of common high-pressure refrigerants [may use standard temperature-pressure chart--be aware of need to add 14.7 to translate pounds per square inch gauge (psig) to pounds per square inch absolute (psia)]	Type 2, Refrigeration
130°F	Need to heat oil to 130°F before removing it to minimize refrigerant release	Type 3, Recovery Techniques

What this page leaves out

Gauge colors, pressure-temperature values, leak rates, the maximum penalty and the evacuation levels are on EPA’s list as topics, but EPA’s list does not give the values, so this page does not either. The regulation does for some of them (evacuation levels are in Table 1 of § 82.156); read it for the value you need. [40 CFR 82.156]

When you have read a section, test yourself on the free practice test.

Sources

Every fact on this page was checked against these sources on October 24, 2026. noshu is not affiliated with the U.S. Environmental Protection Agency or any EPA-approved certifying organization, and this is an unofficial study aid: EPA’s Section 608 pages, the regulation and your certifying organization are the authority on the test. If something here is wrong, tell us at a@noshu.net.