30 questions split evenly across the four sections of the EPA Section 608 Technician Certification exam: Core, Type I, Type II and Type III, built on EPA's published test topics. Instant answers, plain explanations, and a score by section at the end.
30
Questions
4
Domains, real weights
100%
Answers sourced
0
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How this test is weighted
Core
25% of the EPA 608
8 questions here
Type I (small appliances)
25% of the EPA 608
7 questions here
Type II (high-pressure)
25% of the EPA 608
8 questions here
Type III (low-pressure)
25% of the EPA 608
7 questions here
Click an answer to check it. Each question shows why the answer is right and the public source it comes from (EPA Section 608 pages, 40 CFR Part 82 Subpart F).
Q1 · Core
A technician is recovering refrigerant from an older residential split system charged with R-22. How is R-22 classified?
The answer is B. R-22 (HCFC-22) is a hydrochlorofluorocarbon, a class II ozone-depleting substance. EPA's Core topics use exactly this example: R-12 is a CFC, R-22 is an HCFC and R-134a is an HFC.
Why does HFC-134a (R-134a) have an ozone depletion potential (ODP) of zero?
The answer is D. Ozone depletion in the stratosphere is driven by chlorine (and bromine) released from ozone-depleting substances. EPA's glossary states that HFCs have zero ODP because they do not contain chlorine. HFC-134a still has a significant global warming potential, which is a separate issue.
Under the U.S. phaseout schedule for HCFCs, in which year did all production and import of HCFC-22 (R-22) end?
The answer is A. EPA's class II phaseout table shows that 2020 brought no production or import of HCFC-22 or HCFC-142b. In 2010 production of R-22 was limited to servicing equipment made before 2010; 2030 is the date for the complete phaseout of all HCFCs. Existing R-22 systems are now serviced with recovered, reclaimed or stockpiled refrigerant.
A mechanic who holds only Section 609 (motor vehicle air conditioning) certification tries to buy a 25-pound cylinder of R-410A at a supply house to recharge a rooftop unit. What does the refrigerant sales restriction say?
The answer is C. Since January 1, 2018 the sales restriction also covers non-exempt substitutes such as HFCs. EPA states that only Section 608-certified technicians can purchase refrigerants intended for stationary refrigeration and air-conditioning equipment, and that Section 609 technicians cannot buy refrigerant for stationary equipment regardless of container size.
What does the term "fractionation" describe when working with refrigerant blends?
The answer is A. EPA's Core topics define the fractionation problem as the tendency of the different components of blends to leak at different rates. After a leak, the refrigerant left in the system no longer has its original composition.
A contractor recovers R-22 from one customer's air conditioner and wants to sell it to a different building owner for use in that owner's equipment. What must happen before the sale?
The answer is C. Recovered refrigerant may go back into the same system or other systems owned by the same person. If it changes ownership it must be reclaimed by an EPA-certified reclaimer, which reprocesses it to the purity in Appendix A of Subpart F (based on AHRI Standard 700-2016) and verifies it by lab analysis. Recycling only cleans refrigerant for reuse in equipment of the same owner.
To leave room for the liquid to expand, a refillable recovery cylinder should not be filled beyond what share of its capacity?
The answer is B. EPA's Core safety topics include the risks of filling cylinders more than 80 percent full. Liquid refrigerant expands as it warms, and an overfilled cylinder can become liquid-full and build dangerous pressure.
A technician needs to pressurize a system to look for a leak. Which setup is correct?
The answer is D. EPA's Core safety topics call for nitrogen rather than oxygen or compressed air for leak testing, used with a pressure regulator and a relief valve. Refrigerant safety data sheets warn not to mix refrigerant with oxygen or air above atmospheric pressure.
Source: EPA: Section 608 Technician Certification Test Topics, Core: Safety (use of nitrogen rather than oxygen or compressed air; pressure regulator and relief valve with nitrogen); oxygen/air warning from Hudson Technologies Used Refrigerant SDS, Section 10
Q9 · Type I (small appliances)
Which of these counts as a "small appliance" under the Section 608 rules?
The answer is C. A small appliance is fully manufactured, charged and hermetically sealed in a factory with five pounds or less of refrigerant; vending machines are named as an example. A field-charged split system is not factory-sealed, a 12-pound walk-in exceeds five pounds, and motor vehicle air conditioners are a separate category.
A technician uses recovery equipment manufactured in 2022 to recover refrigerant from a household refrigerator whose compressor still runs. What share of the refrigerant must be recovered (if not evacuating to a vacuum level instead)?
The answer is A. For small appliances, recovery equipment made on or after November 15, 1993 must recover 90 percent of the refrigerant when the appliance's compressor works and 80 percent when it does not. Equipment made before that date needs 80 percent either way.
Instead of meeting a percentage recovery requirement, a technician servicing a window air conditioner can also satisfy the small-appliance recovery rule by evacuating the appliance to what level?
The answer is D. The rule lets technicians meet the small-appliance requirement by evacuating the appliance to four inches of mercury vacuum, as an alternative to the 80 or 90 percent recovery levels.
Source: eCFR: 40 CFR 82.156, (b)(3) Small appliances: evacuate the appliance to four inches of mercury vacuum
Q12 · Type I (small appliances)
A dorm refrigerator has a seized compressor. The technician will recover the refrigerant with a system-dependent (passive) recovery device. What should be done to get adequate recovery?
The answer is B. EPA's Type I topics list the need to install both high- and low-side access valves when recovering refrigerant from small appliances with inoperative compressors. Heating and sharply striking the compressor can also help free refrigerant trapped in the oil.
A technician used a solderless (bolt-on, line-piercing) access fitting to service a small appliance. What should be done with it when the job is finished?
The answer is A. EPA's Type I topics state that solderless access fittings should be removed at the conclusion of service.
Which refrigerant became the common substitute for CFC-12 (R-12) in household refrigerators and other small appliances?
The answer is B. EPA's Type I topics name HFC-134a (R-134a) as the likely substitute for CFC-12 (R-12). R-11 and R-123 are low-pressure chiller refrigerants, and R-22 is itself an ozone-depleting HCFC.
A technician is brazing near a leaking refrigeration line that contains a chlorine-containing refrigerant. What hazard does the open flame create?
The answer is C. EPA's Type I safety topic covers decomposition products of refrigerants at high temperatures. A refrigerant safety data sheet lists thermal decomposition products including hydrogen fluoride, hydrogen chloride, carbon monoxide and possibly carbonyl halides such as phosgene, all toxic and irritating.
According to EPA's Section 608 test topics, which gas is the best choice for pressurizing a high-pressure system to leak test it?
The answer is D. EPA's Type II topics give the order of preference for leak test gases: nitrogen alone is best, and nitrogen with a trace of HCFC-22 is better than pure refrigerant. Compressed air is not used for leak testing (the Core topics call for nitrogen instead of oxygen or compressed air).
An office building's R-22 rooftop comfort-cooling unit has a full charge of 80 pounds. A technician adds 6 pounds to return it to full charge 120 days after the last refrigerant addition. Using the annualizing method, what is the leak rate, to the nearest tenth of a percent?
The answer is A. Annualizing method: (pounds added / full charge) / (days since last addition / 365) x 100 = (6/80) / (120/365) x 100 = 22.8%. That exceeds the 10 percent trigger rate for comfort cooling, so the owner must have the leak found and repaired within 30 days (or make a retrofit or retirement plan).
Source: eCFR: 40 CFR 82.152, Definition of leak rate, (1) Annualizing Method; trigger rate in 82.157(c)(2)(iii)
Q18 · Type II (high-pressure)
A supermarket's R-22 refrigeration rack has a full charge of 450 pounds. The owner calculates a leak rate of 25 percent. What does EPA's leak repair rule require?
The answer is C. For appliances with 50 or more pounds of ozone-depleting refrigerant, the trigger rates are 20 percent for commercial refrigeration (retail food and cold storage), 30 percent for industrial process refrigeration and 10 percent for comfort cooling and other appliances. Above the trigger, the owner must repair within 30 days or develop a retrofit or retirement plan within 30 days.
After reaching the required recovery vacuum on a high-pressure appliance, a technician isolates the system and waits a few minutes. The system pressure rises. What does this most likely mean?
The answer is B. EPA's Type II topics include the need to wait a few minutes after reaching the required recovery vacuum to see if system pressure rises, which indicates that liquid refrigerant remains in the system or in the oil. The technician should continue recovering.
Using recovery equipment manufactured in 2020, a technician must open an R-410A high-pressure appliance with a 250-pound full charge for a major repair. To what level must the appliance be evacuated before it is opened?
The answer is D. R-410A appliances are high-pressure appliances. For a high-pressure appliance with a full charge of 200 pounds or more, equipment made on or after November 15, 1993 must reach 10 inches of mercury vacuum (4 inches with older equipment). Under 200 pounds the level is 0 inches; 15 inches applies to medium-pressure appliances of 200 pounds or more.
Source: eCFR: 40 CFR 82.156, Table 1, Required Levels of Evacuation for Appliances; definition of high-pressure appliance in 82.152
Q21 · Type II (high-pressure)
System-dependent recovery equipment may not be used on appliances with a full charge above how many pounds of refrigerant, unless it is permanently attached as a pump-out unit?
The answer is A. The rule states that system-dependent equipment may not be used with appliances with a full charge of more than 15 pounds of refrigerant unless the equipment is permanently attached to the appliance as a pump-out unit.
A technician reads 118 psig on the gauge of a running system and wants to use a pressure-temperature chart printed in absolute pressure. What is the absolute pressure?
The answer is B. Gauge pressure is measured relative to the atmosphere, so add atmospheric pressure (14.7 psi) to convert: 118 + 14.7 = 132.7 psia. EPA's Type II topics note the need to add 14.7 to translate psig to psia.
A technician has just finished evacuating a system that has a hermetic compressor and the system is still under a deep vacuum. What should the technician do before energizing the compressor?
The answer is C. EPA's Type II safety topics say technicians should not energize hermetic compressors under vacuum. Tecumseh's service handbook warns never to start the compressor under deep vacuum, to break the vacuum with refrigerant charge first, and that doing otherwise can damage the hermetic terminal.
The purge unit on an R-123 low-pressure chiller has started running far more often than usual. What does this most likely indicate?
The answer is A. R-11, R-113 and R-123 boil at or above room temperature, so parts of a low-pressure chiller run below atmospheric pressure and leaks pull air and moisture in rather than letting refrigerant out. The purge unit removes these noncondensables, and EPA lists excessive purging as a sign of leakage into a low-pressure system.
Source: EPA: Section 608 Technician Certification Test Topics, Type 3: Leak Detection (signs of leakage into a low-pressure system, e.g., excessive purging); boiling points from 40 CFR Part 82 Subpart F Appendix B1, 8.2.2 Gas Phase sampling
Q25 · Type III (low-pressure)
A technician will make a non-major repair on a low-pressure chiller that uses R-123 and will not evacuate it afterward. The chiller must be brought to 0 psig before it is opened. Which method should be used?
The answer is D. Low-pressure appliances must be pressurized to no higher than 0 psig before opening for a non-major repair. For refrigerants that boil at or below 85 degrees F at atmospheric pressure, methods such as nitrogen that require later purging may not be used, and R-123 boils at about 81 degrees F (300.2 K, NIST Chemistry WebBook). EPA's Type III topics name controlled hot water and system heating/pressurization devices as the allowable methods.
Before draining oil from a low-pressure chiller, to what temperature should the oil be heated to reduce the amount of refrigerant released?
The answer is B. EPA's Type III recovery topics state the need to heat oil to 130 degrees F before removing it, to minimize refrigerant release. Warm oil holds less dissolved refrigerant.
An R-11 chiller with a full charge of 300 pounds needed 400 pounds of refrigerant added during one calendar year. What reporting does EPA's leak rule require of the owner?
The answer is C. Appliances with 50 or more pounds of refrigerant that leak 125 percent or more of their full charge in a calendar year are chronically leaking. 400 of 300 pounds is about 133 percent, so the owner must report to EPA by March 1 of the following year, describing efforts to identify leaks and repair the appliance.
When recharging a low-pressure centrifugal chiller after it has been evacuated, why is refrigerant vapor introduced before liquid?
The answer is A. EPA's Type III recharging topics state the need to introduce vapor before liquid to prevent freezing of water in the tubes. The same topics call for charging centrifugal chillers through the evaporator charging valve.
To what level must a low-pressure appliance be evacuated before it is opened for a major repair or disposal?
The answer is D. Table 1 of the evacuation rule sets 25 mm Hg absolute for low-pressure appliances, whether the recovery equipment was made before or after November 15, 1993.
Source: eCFR: 40 CFR 82.156, Table 1, Required Levels of Evacuation for Appliances (low-pressure appliance)
Q30 · Type III (low-pressure)
Under ASHRAE Standard 15, what must the mechanical equipment room of an R-123 chiller have, as covered by EPA's Type III topics?
The answer is B. EPA's Type III safety topics state that under ASHRAE Standard 15 the equipment room needs a refrigerant sensor for R-123, in addition to the oxygen deprivation sensor that applies with all refrigerants.
Four sections of 25 questions each: Core plus Type I (small appliances), Type II (high-pressure) and Type III (low-pressure). The pass mark is 70 percent, 18 of 25 per section. Pass all four for Universal certification.
Closed-book and proctored for Type II, Type III and Universal. Type I alone may be offered as a mail-in test, which needs 84 percent (21 of 25) and cannot count toward Universal.
Fees and time limits are set by each EPA-approved certifying organization, not by EPA, and some offer remote testing. The certification never expires, and since 2018 it covers HFC refrigerants as well as CFCs and HCFCs.
From EPA's official EPA Section 608 test topics. CertOutlook is not affiliated with EPA. Practice questions are original and are not taken from the exam.