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EPA 608 Core practice test

Ozone depletion, the Clean Air Act, Section 608 rules, the three Rs, recovery basics, safety and shipping. Every 608 test includes 25 Core questions.

100 questions, grouped by the topics on EPA's test outline. Answer one to see whether you were right, why, and where the rule comes from. Printable version with answers (save as PDF).

Set 1 of 10. 0 of 100 questions answered.

Environmental impacts

How CFCs and HCFCs destroy stratospheric ozone, and what that does to health and the environment.

Question 1 of 14

Which element in CFC and HCFC refrigerants is responsible for destroying ozone in the stratosphere?

Question 2 of 14

R-12 belongs to which family of refrigerants?

Question 3 of 14

A technician is servicing an older split system charged with R-22. What type of refrigerant is R-22?

Question 4 of 14

A customer asks why R-134a is said to have an ozone depletion potential of zero. What is the reason?

Question 5 of 14

Which list puts the refrigerant families in order from highest to lowest ozone depletion potential?

Question 6 of 14

Ozone depletion potential (ODP) compares a substance with a reference refrigerant whose ODP is set at 1.0. Which refrigerant is that reference?

Question 7 of 14

What does the ozone layer in the stratosphere do that protects people at ground level?

Question 8 of 14

Which health effect is linked to thinning of the stratospheric ozone layer?

Question 9 of 14

Besides harm to human health, which environmental effect is expected from stratospheric ozone depletion?

Question 10 of 14

Why are CFC molecules released at ground level able to reach the stratosphere?

Question 11 of 14

What finally breaks a CFC molecule apart once it reaches the stratosphere?

Question 12 of 14

Why can a single chlorine atom released from a CFC destroy many ozone molecules rather than just one?

Question 13 of 14

Which observation is part of the evidence that CFCs and HCFCs are thinning the ozone layer?

Question 14 of 14

R-410A does not deplete ozone. Why is releasing it to the atmosphere still an environmental concern?

14 questions in this set are still unanswered. You can move on without answering them.

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Answer key: every answer, explained

The correct answer to every question above, with why it is right, why each other choice is wrong, and the source. Open a question to see its answer.

Environmental impacts

1. Which element in CFC and HCFC refrigerants is responsible for destroying ozone in the stratosphere?
  • Fluorine
  • Carbon
  • ChlorineCorrect answer
  • Hydrogen

Why “Chlorine” is correct

CFCs and HCFCs contain chlorine. When ultraviolet light breaks these molecules apart high in the stratosphere, the chlorine atoms that are freed attack ozone. That is why chlorine-free refrigerants such as HFCs have an ozone depletion potential of zero.

Source: EPA: Test Topics

Why the other answers are wrong

  • Fluorine — Fluorine is in CFCs, HCFCs and HFCs alike, yet HFCs do not deplete ozone, so fluorine is not the culprit.
  • Carbon — Carbon is the backbone of the molecule but does not attack ozone.
  • Hydrogen — Hydrogen is what makes HCFCs break down sooner in the lower atmosphere; it does not destroy ozone.

This question on its own page

2. R-12 belongs to which family of refrigerants?
  • CFCCorrect answer
  • HFC
  • HCFC
  • HFO

Why “CFC” is correct

R-12 is a chlorofluorocarbon (CFC): it contains chlorine, fluorine and carbon and no hydrogen. CFCs such as R-11 and R-12 have the highest ozone depletion potential of the common refrigerants.

Source: EPA: Test Topics

Why the other answers are wrong

  • HFC — HFCs such as R-134a replaced R-12; they contain no chlorine.
  • HCFC — R-22 is the classic HCFC; R-12 has no hydrogen in it.
  • HFO — HFOs are newer low-GWP substitutes, not the older refrigerant R-12.

This question on its own page

3. A technician is servicing an older split system charged with R-22. What type of refrigerant is R-22?
  • Hydrocarbon
  • CFC
  • HFC
  • HCFCCorrect answer

Why “HCFC” is correct

R-22 is a hydrochlorofluorocarbon (HCFC). It still contains chlorine, so it depletes ozone, but its added hydrogen makes it break down more in the lower atmosphere, giving it a much lower ozone depletion potential than a CFC.

Source: EPA: Test Topics

Why the other answers are wrong

  • Hydrocarbon — Hydrocarbons such as propane (R-290) contain only hydrogen and carbon.
  • CFC — CFCs such as R-12 and R-11 have no hydrogen; R-22 does.
  • HFC — HFCs such as R-410A and R-134a contain no chlorine; R-22 does.

This question on its own page

4. A customer asks why R-134a is said to have an ozone depletion potential of zero. What is the reason?
  • It breaks down completely in the lower atmosphere
  • It contains no chlorine to attack ozoneCorrect answer
  • It is heavier than air and stays near the ground
  • It is used only in small amounts

Why “It contains no chlorine to attack ozone” is correct

R-134a is an HFC, made of hydrogen, fluorine and carbon. With no chlorine (or bromine) in the molecule, it cannot carry ozone-destroying atoms into the stratosphere, so its ODP is zero. Some HFCs still have a high global warming potential.

Source: EPA: Test Topics

Why the other answers are wrong

  • It breaks down completely in the lower atmosphere — HFCs are not destroyed before reaching the upper atmosphere; they simply carry no chlorine.
  • It is heavier than air and stays near the ground — Refrigerant vapors mix through the whole atmosphere over time regardless of density.
  • It is used only in small amounts — The amount used has nothing to do with ODP, which is a property of the chemical.

This question on its own page

5. Which list puts the refrigerant families in order from highest to lowest ozone depletion potential?
  • HCFC, CFC, HFC
  • HFC, HCFC, CFC
  • CFC, HCFC, HFCCorrect answer
  • CFC, HFC, HCFC

Why “CFC, HCFC, HFC” is correct

CFCs carry the most chlorine to the stratosphere and have the highest ODP. HCFCs have far lower ODPs (about 0.01 to 0.1) because much of each molecule breaks down lower in the atmosphere. HFCs contain no chlorine and have an ODP of zero.

Source: EPA: Test Topics

Why the other answers are wrong

  • HCFC, CFC, HFC — CFCs, not HCFCs, have the highest ODP.
  • HFC, HCFC, CFC — This is the order reversed; HFCs are lowest at zero.
  • CFC, HFC, HCFC — HFCs have zero ODP, so they cannot sit above HCFCs.

This question on its own page

6. Ozone depletion potential (ODP) compares a substance with a reference refrigerant whose ODP is set at 1.0. Which refrigerant is that reference?
  • R-22
  • R-11Correct answer
  • R-134a
  • R-410A

Why “R-11” is correct

ODP is the ratio of a chemical's impact on ozone to that of the same mass of CFC-11 (R-11), whose ODP is defined as 1.0. Other CFCs and HCFCs are rated against it, and HFCs come out at zero.

Source: EPA: Test Topics

Why the other answers are wrong

  • R-22 — R-22 is an HCFC with an ODP well below 1.
  • R-134a — R-134a is an HFC with an ODP of zero.
  • R-410A — R-410A is an HFC blend with an ODP of zero.

This question on its own page

7. What does the ozone layer in the stratosphere do that protects people at ground level?
  • It filters smog and dust out of the air
  • It traps heat near the surface to keep the earth warm at night
  • It produces the oxygen that people breathe
  • It absorbs much of the sun's ultraviolet radiationCorrect answer

Why “It absorbs much of the sun's ultraviolet radiation” is correct

Stratospheric ozone absorbs much of the ultraviolet (UV) radiation coming from the sun. When chlorine thins that layer, more UV reaches the surface, which is why ozone depletion is a health and environmental problem.

Source: EPA: Test Topics

Why the other answers are wrong

  • It filters smog and dust out of the air — Smog and dust are lower-atmosphere pollution; the ozone layer does not filter them.
  • It traps heat near the surface to keep the earth warm at night — Trapping heat is the greenhouse effect, a separate issue from ozone shielding.
  • It produces the oxygen that people breathe — Breathable oxygen comes mainly from plants and plankton, not the ozone layer.

This question on its own page

8. Which health effect is linked to thinning of the stratospheric ozone layer?
  • More cases of skin cancer and cataractsCorrect answer
  • Higher rates of food poisoning
  • More frequent heat stroke in summer
  • Increased hearing loss in adults

Why “More cases of skin cancer and cataracts” is correct

A thinner ozone layer lets more ultraviolet radiation reach the ground. Greater UV exposure raises the risk of skin cancer and eye cataracts and can weaken the immune system.

Source: EPA: Test Topics

Why the other answers are wrong

  • Higher rates of food poisoning — Food poisoning comes from bacteria, not ultraviolet exposure.
  • More frequent heat stroke in summer — Heat stroke is driven by air temperature, not by UV getting through the ozone layer.
  • Increased hearing loss in adults — Hearing loss has no link to ultraviolet radiation.

This question on its own page

9. Besides harm to human health, which environmental effect is expected from stratospheric ozone depletion?
  • Lower crop yields and harm to ocean planktonCorrect answer
  • Faster growth of forests and grasslands
  • Cooler summers across most of the world
  • Less acid rain over industrial areas

Why “Lower crop yields and harm to ocean plankton” is correct

Extra ultraviolet radiation reaching the surface can damage crops and harm plankton and other marine life near the ocean surface. Because plankton sit at the base of the ocean food chain, the damage can spread to fish and other species.

Source: EPA: Test Topics

Why the other answers are wrong

  • Faster growth of forests and grasslands — More UV harms plants; it does not make them grow faster.
  • Cooler summers across most of the world — Ozone depletion is not a cause of cooler summers.
  • Less acid rain over industrial areas — Acid rain comes from sulfur and nitrogen emissions, not from ozone loss.

This question on its own page

10. Why are CFC molecules released at ground level able to reach the stratosphere?
  • They are lighter than air and rise to the stratosphere within hours
  • Rain carries them upward during storms
  • Sunlight in the lower atmosphere turns them into ozone
  • They are very stable and do not break down low in the airCorrect answer

Why “They are very stable and do not break down low in the air” is correct

CFCs are very stable in the troposphere, so instead of breaking down they last long enough for air movement to carry them up into the stratosphere over the years. There strong ultraviolet light finally splits them and releases chlorine.

Source: EPA: Test Topics

Why the other answers are wrong

  • They are lighter than air and rise to the stratosphere within hours — CFC vapors are heavier than air; they reach the stratosphere by slow mixing, not by floating up.
  • Rain carries them upward during storms — Rain washes soluble chemicals down out of the air; it does not lift CFCs.
  • Sunlight in the lower atmosphere turns them into ozone — CFCs are not converted into ozone; they lead to its destruction.

This question on its own page

11. What finally breaks a CFC molecule apart once it reaches the stratosphere?
  • Contact with water vapor in clouds
  • Strong ultraviolet light from the sunCorrect answer
  • Reaction with nitrogen in the air
  • The cold temperatures at high altitude

Why “Strong ultraviolet light from the sun” is correct

In the stratosphere, CFCs are exposed to strong ultraviolet light that does not reach the lower atmosphere. The UV breaks the molecule and frees chlorine atoms, which then go on to destroy ozone.

Source: EPA: Test Topics

Why the other answers are wrong

  • Contact with water vapor in clouds — CFCs do not dissolve or react in water vapor, which is why they survive so long.
  • Reaction with nitrogen in the air — Nitrogen in the air does not break CFC molecules apart.
  • The cold temperatures at high altitude — Cold alone does not split the molecule; it takes UV energy.

This question on its own page

12. Why can a single chlorine atom released from a CFC destroy many ozone molecules rather than just one?
  • It splits into several smaller atoms after each reaction
  • It combines with fluorine to form new chlorine
  • It is freed again after each reaction and keeps goingCorrect answer
  • It turns ozone into more CFC molecules

Why “It is freed again after each reaction and keeps going” is correct

Chlorine acts as a catalyst. It breaks an ozone molecule, and through a follow-up reaction the chlorine atom is released again to attack more ozone. One atom can repeat this cycle many times before it is finally tied up in a stable compound.

Source: EPA: Test Topics

Why the other answers are wrong

  • It splits into several smaller atoms after each reaction — An atom does not split into more chlorine atoms in these reactions.
  • It combines with fluorine to form new chlorine — Chlorine is not created from fluorine; the same chlorine atom is recycled.
  • It turns ozone into more CFC molecules — Ozone is turned into ordinary oxygen, not into CFCs.

This question on its own page

13. Which observation is part of the evidence that CFCs and HCFCs are thinning the ozone layer?
  • Chlorine levels in the stratosphere matching volcanic activity
  • Steady increases in ozone over the poles since the 1950s
  • Ozone levels rising wherever CFC sales went up
  • Ozone loss over Antarctica alongside high chlorine levelsCorrect answer

Why “Ozone loss over Antarctica alongside high chlorine levels” is correct

Scientists have measured deep seasonal ozone losses over Antarctica, the so-called ozone hole, in the same stratospheric air where chlorine compounds from CFCs are high. That pairing of ozone loss with man-made chlorine is a key part of the evidence.

Source: EPA: Test Topics

Why the other answers are wrong

  • Chlorine levels in the stratosphere matching volcanic activity — Stratospheric chlorine tracks CFC use, not volcanic activity.
  • Steady increases in ozone over the poles since the 1950s — Polar ozone has fallen, not risen, since CFCs came into wide use.
  • Ozone levels rising wherever CFC sales went up — Ozone falls, not rises, as chlorine from CFCs builds up.

This question on its own page

14. R-410A does not deplete ozone. Why is releasing it to the atmosphere still an environmental concern?
  • It has a high global warming potentialCorrect answer
  • It turns into smog at ground level
  • It breaks down into chlorine in sunlight
  • It reacts with ozone in the lower atmosphere

Why “It has a high global warming potential” is correct

R-410A is an HFC blend with zero ozone depletion potential, but many HFCs have a high global warming potential (GWP). Released refrigerant traps heat in the atmosphere, so venting HFCs is still prohibited.

Source: EPA: Test Topics

Why the other answers are wrong

  • It turns into smog at ground level — R-410A is not a smog-forming pollutant.
  • It breaks down into chlorine in sunlight — HFCs contain no chlorine, so they cannot release it.
  • It reacts with ozone in the lower atmosphere — With no chlorine, R-410A does not destroy ozone at any altitude.

This question on its own page

Clean Air Act and Montreal Protocol

15. What is the Montreal Protocol?
  • A U.S. law that sets fines for venting refrigerant
  • An international treaty phasing out ozone-depleting substancesCorrect answer
  • An industry standard for the purity of reclaimed refrigerant
  • A federal program that tests and certifies recovery machines

Why “An international treaty phasing out ozone-depleting substances” is correct

The Montreal Protocol on Substances That Deplete the Ozone Layer is the international agreement that controls and phases out the production of ozone-depleting substances such as CFCs and HCFCs. The Clean Air Act carries out the U.S. part of those commitments.

Source: EPA: Test Topics

Why the other answers are wrong

  • A U.S. law that sets fines for venting refrigerant — Fines for venting come from the U.S. Clean Air Act, not the treaty.
  • An industry standard for the purity of reclaimed refrigerant — Reclaimed refrigerant purity is set by AHRI Standard 700.
  • A federal program that tests and certifies recovery machines — Recovery machines are certified by EPA-approved equipment testing organizations.

This question on its own page

16. In the United States, production of CFC refrigerants such as R-12 for general use ended on which date?
  • January 1, 1992
  • January 1, 1996Correct answer
  • January 1, 2010
  • January 1, 2020

Why “January 1, 1996” is correct

U.S. production and import of CFCs ended at the end of 1995, so from January 1, 1996 no new CFC refrigerant was made for general use. Equipment still running on CFCs is serviced with recovered, recycled or reclaimed refrigerant.

Source: EPA: Test Topics

Why the other answers are wrong

  • January 1, 1992 — 1992 is too early; U.S. CFC production continued until the end of 1995.
  • January 1, 2010 — 2010 is tied to the HCFC (R-22) phaseout for new equipment.
  • January 1, 2020 — 2020 is when production and import of R-22 ended.

This question on its own page

17. Production and import of new R-22 in the United States ended on January 1, 2020. How can existing R-22 systems still be serviced?
  • Only by replacing the entire system with a new HFC system
  • With any HFC added on top of the R-22 charge
  • With recovered, recycled or reclaimed R-22Correct answer
  • Only with R-22 imported under a special permit

Why “With recovered, recycled or reclaimed R-22” is correct

The phaseout stopped new production and import, not the use of existing R-22. Systems can keep running and be serviced with R-22 that has been recovered and recycled or reclaimed, or that was produced before the deadline.

Source: EPA: Test Topics

Why the other answers are wrong

  • Only by replacing the entire system with a new HFC system — The phaseout does not force owners to replace working systems.
  • With any HFC added on top of the R-22 charge — Topping off with a different refrigerant creates a mixture that is hard to reclaim and may damage the system.
  • Only with R-22 imported under a special permit — There is no general import permit for servicing; new imports ended.

This question on its own page

18. Under the HCFC phaseout, what changed for R-22 starting January 1, 2010?
  • It could not be produced or imported for new equipmentCorrect answer
  • It could no longer be used to service any existing systems
  • It was reclassified as a substitute refrigerant
  • It could only be sold to Type III technicians

Why “It could not be produced or imported for new equipment” is correct

The R-22 phaseout came in steps. From January 1, 2010, R-22 could not be produced or imported for charging newly made equipment, while production for servicing existing systems continued until January 1, 2020.

Source: EPA: Test Topics

Why the other answers are wrong

  • It could no longer be used to service any existing systems — Servicing existing systems with R-22 is still allowed today.
  • It was reclassified as a substitute refrigerant — R-22 is an HCFC, a class II ozone-depleting substance, not a substitute.
  • It could only be sold to Type III technicians — R-22 is mainly a high-pressure refrigerant; Type III covers low-pressure equipment.

This question on its own page

19. While replacing a compressor, a technician knowingly opens the valves and lets an R-22 charge blow to the air instead of recovering it. Under the Clean Air Act rules, this is:
  • Allowed if the charge is under 50 pounds
  • A violation only if a customer reports it
  • Allowed if the refrigerant is contaminated
  • A violation of the venting prohibitionCorrect answer

Why “A violation of the venting prohibition” is correct

40 CFR 82.154(a) makes it illegal for anyone maintaining, servicing, repairing or disposing of an appliance to knowingly vent or release refrigerant. Refrigerant must be recovered with certified equipment before the system is opened.

Source: 40 CFR 82.154(a)

Why the other answers are wrong

  • Allowed if the charge is under 50 pounds — The 50-pound figure is a leak repair threshold, not a venting allowance.
  • A violation only if a customer reports it — A violation is a violation whether or not anyone reports it.
  • Allowed if the refrigerant is contaminated — Contaminated refrigerant must still be recovered; it can be sent for reclamation or destruction.

This question on its own page

20. A crew is tearing out an old R-22 rooftop unit for scrap. What does the venting prohibition require of them?
  • Nothing, because disposal is not servicing
  • Release the refrigerant slowly outdoors
  • Recover the refrigerant instead of releasing itCorrect answer
  • Ask the owner to sign a venting waiver

Why “Recover the refrigerant instead of releasing it” is correct

The venting prohibition covers disposal as well as service. Anyone disposing of an appliance may not knowingly release its refrigerant, and equipment dismantled on site must have its refrigerant recovered before disposal.

Source: 40 CFR 82.154(a); EPA: Safe Disposal Requirements

Why the other answers are wrong

  • Nothing, because disposal is not servicing — The rule names disposal along with maintenance, service and repair.
  • Release the refrigerant slowly outdoors — Releasing slowly is still knowingly venting.
  • Ask the owner to sign a venting waiver — No owner waiver allows refrigerant to be vented.

This question on its own page

21. Does the venting prohibition apply to HFC substitute refrigerants such as R-410A and R-134a?
  • No, it covers only CFCs and HCFCs
  • Only for equipment built after 2018
  • Only when the system holds more than 50 pounds
  • Yes, non-exempt substitutes are covered tooCorrect answer

Why “Yes, non-exempt substitutes are covered too” is correct

The prohibition in 40 CFR 82.154(a) applies to any refrigerant in an appliance, including substitutes. Only the specific substitutes and end-uses listed as exempt, such as carbon dioxide, nitrogen and water, may be released.

Source: 40 CFR 82.154(a)

Why the other answers are wrong

  • No, it covers only CFCs and HCFCs — Substitutes such as HFCs are covered unless specifically exempted.
  • Only for equipment built after 2018 — The prohibition does not depend on the date the equipment was made.
  • Only when the system holds more than 50 pounds — There is no charge-size limit on the venting prohibition.

This question on its own page

22. Which of these may be released without violating the venting prohibition?
  • R-410A drained from a system before a coil change
  • R-134a from a disposable cylinder heel
  • Pure nitrogen used to pressure-test a line setCorrect answer
  • R-22 removed during an oil change

Why “Pure nitrogen used to pressure-test a line set” is correct

40 CFR 82.154(a)(1) lists substances exempt from the venting prohibition, including nitrogen in any application, carbon dioxide and water. Pure nitrogen used for a pressure test can be released. HFCs and HCFCs must be recovered.

Source: 40 CFR 82.154(a)(1)

Why the other answers are wrong

  • R-410A drained from a system before a coil change — R-410A is a non-exempt substitute; removing it before opening the system means recovering it, not venting it.
  • R-134a from a disposable cylinder heel — The heel of a disposable cylinder must be recovered, not vented.
  • R-22 removed during an oil change — Refrigerant in oil must be recovered; oil changes have their own pressure limit.

This question on its own page

23. How are civil penalties counted for violations of the Clean Air Act refrigerant rules?
  • Per violation, for each day the violation continuesCorrect answer
  • One flat fine per company per year
  • Per technician, only after a second offense
  • Per pound vented, with no daily count

Why “Per violation, for each day the violation continues” is correct

Clean Air Act penalties are assessed per violation and per day, so a violation that continues for many days can carry a very large total. The maximum daily amount is set by statute and adjusted for inflation each year.

Source: EPA: Test Topics

Why the other answers are wrong

  • One flat fine per company per year — Penalties are not a single yearly fine; each day can count separately.
  • Per technician, only after a second offense — A first offense can be penalized; there is no free first violation.
  • Per pound vented, with no daily count — Penalties are not set per pound of refrigerant released.

This question on its own page

24. Which release is treated as de minimis, and so does not violate the venting prohibition?
  • Venting a nearly empty system that holds less than one pound
  • A small loss while connecting hoses during proper recoveryCorrect answer
  • Releasing refrigerant that is too dirty to recycle
  • Purging a recovery cylinder that was overfilled

Why “A small loss while connecting hoses during proper recovery” is correct

Under 40 CFR 82.154(a)(2), de minimis releases are those that happen during good-faith recovery while the required practices are followed and certified equipment is used, such as a small loss when hoses are connected. Deliberate venting of any amount is not de minimis.

Source: 40 CFR 82.154(a)(2)

Why the other answers are wrong

  • Venting a nearly empty system that holds less than one pound — Knowingly venting a small charge is still a violation.
  • Releasing refrigerant that is too dirty to recycle — Dirty refrigerant must be recovered for reclamation or destruction, not vented.
  • Purging a recovery cylinder that was overfilled — Releasing recovered refrigerant is a violation under 82.154(a)(3).

This question on its own page

25. A technician recovers R-22 into a cylinder and later opens the cylinder valve to empty it outdoors. Is this a violation?
  • No, the refrigerant was already out of the appliance
  • Yes, releasing refrigerant after recovery is ventingCorrect answer
  • No, as long as it happens away from buildings
  • Yes, but only if the cylinder held over 15 pounds

Why “Yes, releasing refrigerant after recovery is venting” is correct

40 CFR 82.154(a)(3) says the knowing release of a class I or II refrigerant or non-exempt substitute after it has been recovered from an appliance is a violation of the venting prohibition. Recovered refrigerant must be reused, recycled, reclaimed or destroyed.

Source: 40 CFR 82.154(a)(3)

Why the other answers are wrong

  • No, the refrigerant was already out of the appliance — The rule specifically covers refrigerant released after recovery.
  • No, as long as it happens away from buildings — Location does not matter; any knowing release is prohibited.
  • Yes, but only if the cylinder held over 15 pounds — There is no cylinder-size threshold for this prohibition.

This question on its own page

Section 608 regulations

26. Under 40 CFR 82.152, a low-pressure appliance uses a refrigerant with a liquid-phase saturation pressure below what level at 104 °F?
  • 45 psiaCorrect answer
  • 170 psia
  • 355 psia
  • 15 psig

Why “45 psia” is correct

A low-pressure appliance uses a refrigerant whose saturation pressure at 104 °F is below 45 psia. Examples named in the rule include R-11, R-123, R-113 and R-245fa, which are found mostly in centrifugal chillers.

Source: 40 CFR 82.152

Why the other answers are wrong

  • 170 psia — 170 psia is the line between medium- and high-pressure.
  • 355 psia — 355 psia is the top of the high-pressure range.
  • 15 psig — The definition is written in psia at 104 °F, and 15 psig is not the cutoff.

This question on its own page

27. Under the Section 608 definitions, an appliance charged with R-410A is classified as:
  • Low-pressure
  • Medium-pressure
  • High-pressureCorrect answer
  • Very high-pressure

Why “High-pressure” is correct

40 CFR 82.152 defines a high-pressure appliance as one using a refrigerant with a saturation pressure between 170 and 355 psia at 104 °F, and lists R-22, R-407A, R-407C, R-410A and R-502 as examples.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Low-pressure — Low-pressure refrigerants include R-11 and R-123.
  • Medium-pressure — Medium-pressure examples include R-12 and R-134a.
  • Very high-pressure — Very high-pressure examples include R-13, R-23 and R-503.

This question on its own page

28. Under 40 CFR 82.152, how is an appliance using R-134a classified?
  • Low-pressure
  • Medium-pressureCorrect answer
  • High-pressure
  • Very high-pressure

Why “Medium-pressure” is correct

R-134a has a saturation pressure between 45 and 170 psia at 104 °F, so it is a medium-pressure refrigerant. The rule lists R-114, R-124, R-12, R-134a and R-500 as medium-pressure examples. Type II certification covers medium-, high- and very high-pressure appliances.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Low-pressure — Low-pressure refrigerants such as R-123 are below 45 psia at 104 °F.
  • High-pressure — High-pressure examples are refrigerants like R-22 and R-410A.
  • Very high-pressure — Very high-pressure refrigerants such as R-23 have critical temperatures below 104 °F.

This question on its own page

29. Which refrigerant is given in 40 CFR 82.152 as an example for a very high-pressure appliance?
  • R-500
  • R-123
  • R-407C
  • R-23Correct answer

Why “R-23” is correct

A very high-pressure appliance uses a refrigerant with a critical temperature below 104 °F or a saturation pressure above 355 psia at 104 °F. The rule names R-13, R-23, R-503, R-508A and R-508B, used in very low temperature equipment.

Source: 40 CFR 82.152

Why the other answers are wrong

  • R-500 — R-500 is listed as a medium-pressure refrigerant.
  • R-123 — R-123 is a low-pressure refrigerant used in chillers.
  • R-407C — R-407C is listed as a high-pressure refrigerant.

This question on its own page

30. What is self-contained recovery equipment?
  • Equipment that relies on the appliance's own compressor to move refrigerant
  • A recovery unit that is permanently mounted on the appliance
  • A cylinder that comes pre-evacuated from the factory
  • Equipment that removes refrigerant without help from the applianceCorrect answer

Why “Equipment that removes refrigerant without help from the appliance” is correct

40 CFR 82.152 defines self-contained recovery equipment as equipment able to remove refrigerant from an appliance without the help of components in the appliance. It has its own compressor, so it works even if the appliance compressor does not run.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Equipment that relies on the appliance's own compressor to move refrigerant — Relying on the appliance compressor describes system-dependent equipment.
  • A recovery unit that is permanently mounted on the appliance — Mounting is not what the definition turns on; it turns on whether the equipment needs the appliance's own components.
  • A cylinder that comes pre-evacuated from the factory — A cylinder is a container, not recovery equipment.

This question on its own page

31. Recovery equipment that needs the appliance's own compressor or internal pressure to remove refrigerant is called:
  • System-dependentCorrect answer
  • Self-contained
  • Active recovery
  • Recycling equipment

Why “System-dependent” is correct

System-dependent (passive) recovery equipment requires the help of components in the appliance, such as its compressor or the pressure of the refrigerant, to move refrigerant out. Self-contained equipment does the work with its own compressor.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Self-contained — Self-contained equipment works without help from the appliance.
  • Active recovery — "Active" recovery describes a machine with its own compressor, the opposite of this.
  • Recycling equipment — Recycling equipment cleans refrigerant; the term does not describe where the pumping power comes from.

This question on its own page

32. A technician is paid to repair car air conditioners. Which certification does that work require?
  • Section 608 Type I certification
  • Section 608 Type II certification
  • Section 609 MVAC certificationCorrect answer
  • Section 608 Universal certification

Why “Section 609 MVAC certification” is correct

Motor vehicle air conditioners are not serviced under the Section 608 technician program. Under 40 CFR 82.161(a)(1)(vi), people who service MVACs for pay must be certified under 40 CFR Part 82, Subpart B, the Section 609 program.

Source: 40 CFR 82.161(a)

Why the other answers are wrong

  • Section 608 Type I certification — Type I covers small appliances such as window units and household refrigerators.
  • Section 608 Type II certification — Type II covers stationary medium-, high- and very high-pressure equipment, not cars.
  • Section 608 Universal certification — Universal covers all stationary types but is not the MVAC certification.

This question on its own page

33. A homeowner's split system uses R-410A, an HFC. Is servicing it covered by the Section 608 rules?
  • No, the rules cover only CFC and HCFC refrigerant systems
  • Only if the system was installed before 2010
  • Only if the system holds more than 50 pounds
  • Yes, non-exempt substitutes such as HFCs are coveredCorrect answer

Why “Yes, non-exempt substitutes such as HFCs are covered” is correct

Subpart F applies to anyone servicing appliances containing class I or class II refrigerants or non-exempt substitutes (40 CFR 82.150(b)). Since January 1, 2018 technician certification and the evacuation rules also apply to substitutes such as R-410A.

Source: 40 CFR 82.150(b); 40 CFR 82.161(a)

Why the other answers are wrong

  • No, the rules cover only CFC and HCFC refrigerant systems — Coverage was extended to non-exempt substitutes; HFCs are included.
  • Only if the system was installed before 2010 — Coverage does not depend on installation date.
  • Only if the system holds more than 50 pounds — Charge size matters for leak repair (50 pounds for ozone-depleting refrigerant under Part 82, 15 pounds for HFCs under Part 84), not for whether the rules cover the system.

This question on its own page

34. Recovery and recycling machines made on or after November 15, 1993, must be certified by whom?
  • An EPA-approved equipment testing organizationCorrect answer
  • The technician's employer
  • The refrigerant manufacturer
  • The state licensing board

Why “An EPA-approved equipment testing organization” is correct

Under 40 CFR 82.158(d), manufacturers and importers must have recovery and recycling equipment certified by an approved equipment testing organization, an independent third party approved by EPA. Equipment made before November 15, 1993 is grandfathered if it meets the performance levels in the rule.

Source: 40 CFR 82.158(d)

Why the other answers are wrong

  • The technician's employer — Employers do not certify equipment; independent testing organizations do.
  • The refrigerant manufacturer — Refrigerant makers do not certify recovery machines.
  • The state licensing board — State boards license contractors; EPA rules set equipment certification.

This question on its own page

35. Certified recovery equipment made under 40 CFR 82.158 carries a permanent label. What must that label state?
  • The name and certificate number of the technician who owns it
  • Certification by a named approved testing organizationCorrect answer
  • The refrigerants the owner has recovered with it
  • The date the machine was last serviced

Why “Certification by a named approved testing organization” is correct

Under 40 CFR 82.158(h), certified equipment must carry a lasting label stating that it was certified by the named approved equipment testing organization to meet EPA's minimum requirements, along with the date of manufacture and serial number.

Source: 40 CFR 82.158(h)

Why the other answers are wrong

  • The name and certificate number of the technician who owns it — The label identifies the certification, not the owner.
  • The refrigerants the owner has recovered with it — A log of recovered refrigerant is not part of the certification label.
  • The date the machine was last serviced — Service dates are not required on the certification label.

This question on its own page

36. Recovered refrigerant sold to a new owner must first be reclaimed to which standard?
  • ASHRAE Standard 15
  • UL 1963
  • AHRI Standard 700-2016Correct answer
  • ASHRAE Standard 34

Why “AHRI Standard 700-2016” is correct

40 CFR 82.152 and 82.164 require reclaimed refrigerant to meet the specifications in Appendix A of Subpart F, which is based on AHRI Standard 700-2016, Specifications for Refrigerants. The reclaimer must verify each batch by laboratory analysis.

Source: 40 CFR 82.152; 40 CFR 82.164(a)

Why the other answers are wrong

  • ASHRAE Standard 15 — ASHRAE Standard 15 covers safety in machinery rooms, not refrigerant purity.
  • UL 1963 — UL 1963 is a safety standard for recovery and recycling equipment.
  • ASHRAE Standard 34 — ASHRAE Standard 34 covers refrigerant numbering and safety classes, not purity.

This question on its own page

37. Who may buy R-410A in a 25-pound cylinder for servicing a residential split system?
  • Anyone over 18 with a valid ID
  • A Section 609 certified technician
  • A Section 608 certified technician or an employer of oneCorrect answer
  • A homeowner who signs a statement saying how it will be used

Why “A Section 608 certified technician or an employer of one” is correct

The sales restriction in 40 CFR 82.154(c) allows refrigerant for stationary equipment to be sold only to Section 608 certified technicians, or to employers who show they employ at least one, with limited exceptions such as sales for resale.

Source: 40 CFR 82.154(c); EPA: Sales Restriction

Why the other answers are wrong

  • Anyone over 18 with a valid ID — Age and ID do not meet the sales restriction; certification does.
  • A Section 609 certified technician — Section 609 technicians may buy only refrigerant intended for motor vehicle air conditioners.
  • A homeowner who signs a statement saying how it will be used — A signed statement does not replace certification for a buyer who will use the refrigerant.

This question on its own page

38. A technician holds only Section 609 (MVAC) certification. Can that technician buy R-410A intended for a rooftop unit?
  • Yes, any certified technician may buy any refrigerant
  • Yes, if the container holds less than 30 pounds
  • No, R-410A can be bought only by reclaimers
  • No, 609 certification covers only MVAC refrigerantCorrect answer

Why “No, 609 certification covers only MVAC refrigerant” is correct

EPA's sales restriction lets Section 609 technicians buy only refrigerant acceptable for motor vehicle air conditioners. Refrigerant for stationary equipment, in any container size, may be bought only by Section 608 certified technicians or their employers.

Source: EPA: Sales Restriction; 40 CFR 82.154(c)

Why the other answers are wrong

  • Yes, any certified technician may buy any refrigerant — Buyers may only purchase refrigerant consistent with the appliances their certification covers.
  • Yes, if the container holds less than 30 pounds — Container size does not open stationary refrigerant to 609 technicians.
  • No, R-410A can be bought only by reclaimers — Certified 608 technicians and their employers can buy R-410A.

This question on its own page

39. Which refrigerant sale is allowed to an uncertified buyer under the sales restriction?
  • A 30-pound cylinder of R-22 for a homeowner's own heat pump
  • A small MVAC can (2 lb or less) with a self-sealing valveCorrect answer
  • A 25-pound cylinder of R-410A bought for a home window unit
  • Recovered R-134a sold directly to a neighbor

Why “A small MVAC can (2 lb or less) with a self-sealing valve” is correct

40 CFR 82.154(c)(1)(ix) exempts non-exempt substitute refrigerant intended for MVACs that is sold in containers of two pounds or less with a unique fitting and, for newer cans, a self-sealing valve. Other refrigerant sales require a certified buyer.

Source: 40 CFR 82.154(c)(1)(ix)

Why the other answers are wrong

  • A 30-pound cylinder of R-22 for a homeowner's own heat pump — R-22 for stationary equipment may be sold only to certified technicians or their employers.
  • A 25-pound cylinder of R-410A bought for a home window unit — R-410A cylinders for stationary equipment fall under the sales restriction.
  • Recovered R-134a sold directly to a neighbor — Used refrigerant cannot be sold to a new owner without reclamation, and the buyer must be certified.

This question on its own page

40. A contractor recovers 20 pounds of R-22 from a customer's system. Before selling it to a different owner, what must happen to it?
  • It must be reclaimed by an EPA-certified reclaimerCorrect answer
  • It must be filtered through a recycling machine
  • It must be stored for at least 30 days
  • It must be mixed with fresh R-22 first

Why “It must be reclaimed by an EPA-certified reclaimer” is correct

Under 40 CFR 82.154(d), used refrigerant may not be sold to a new owner unless it has been reclaimed by a reclaimer certified under 82.164 (with narrow exceptions such as transfers within the same company). Recycling alone is not enough.

Source: 40 CFR 82.154(d); EPA: Section 608 Q&A

Why the other answers are wrong

  • It must be filtered through a recycling machine — Recycled refrigerant may go back only into equipment of the same owner.
  • It must be stored for at least 30 days — Storage time does not change the reclamation requirement.
  • It must be mixed with fresh R-22 first — Mixing with new refrigerant does not make used refrigerant legal to sell.

This question on its own page

41. Refrigerant recovered from a customer's walk-in cooler is to be charged into another cooler owned by the same customer. What does the rule require first?
  • It must be tested by a laboratory for acid
  • It must be reclaimed to AHRI 700-2016
  • Nothing more; it may go into the same owner's equipmentCorrect answer
  • It must be approved in writing by the EPA regional office

Why “Nothing more; it may go into the same owner's equipment” is correct

40 CFR 82.156(h) lets recovered refrigerant be returned to the appliance it came from or put into another appliance owned by the same person without being recycled or reclaimed (MVACs and MVAC-like appliances excepted). Good practice is still to recycle refrigerant that may be dirty.

Source: 40 CFR 82.156(h); EPA: Service Practice Requirements

Why the other answers are wrong

  • It must be tested by a laboratory for acid — Laboratory testing is part of reclamation, which is not required here.
  • It must be reclaimed to AHRI 700-2016 — Reclamation is required when the refrigerant changes ownership.
  • It must be approved in writing by the EPA regional office — EPA approval is not needed to reuse refrigerant within one owner.

This question on its own page

42. Which task makes a person a "technician" who needs Section 608 certification?
  • Attaching gauge hoses to an appliance to read pressuresCorrect answer
  • Painting the outside of a condensing unit
  • Replacing a thermostat on the wall
  • Changing the air filter on a furnace

Why “Attaching gauge hoses to an appliance to read pressures” is correct

40 CFR 82.152 defines a technician as anyone who could reasonably be expected to violate the integrity of the refrigerant circuit. Attaching or detaching hoses and gauges, adding or removing refrigerant, adding or removing components and cutting refrigerant lines are listed examples.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Painting the outside of a condensing unit — The definition says painting an appliance is not such an activity.
  • Replacing a thermostat on the wall — Thermostat work does not open the refrigerant circuit.
  • Changing the air filter on a furnace — Filter changes do not touch the refrigerant circuit.

This question on its own page

43. How long must a certified technician keep a copy of the Section 608 certificate?
  • One year after passing the test
  • At work until 3 years after leaving the tradeCorrect answer
  • Until the card expires
  • Only while carrying it on each and every service call

Why “At work until 3 years after leaving the trade” is correct

40 CFR 82.161(a)(4) requires technicians to keep a copy of their certificate at their place of business and to keep it until three years after they stop operating as a technician. EPA does not require carrying the card on calls.

Source: 40 CFR 82.161(a)(4); EPA: Section 608 Q&A

Why the other answers are wrong

  • One year after passing the test — The requirement lasts for the working life of the technician plus three years.
  • Until the card expires — Section 608 certification does not expire.
  • Only while carrying it on each and every service call — EPA does not require technicians to carry the card while working.

This question on its own page

44. How often must a Section 608 certification be renewed?
  • Every two years with a retest
  • Every five years with a retest
  • Every ten years with a retest
  • It does not expireCorrect answer

Why “It does not expire” is correct

Section 608 technician certification does not expire. EPA reserves the right to require recertification in the future by notice in the Federal Register (40 CFR 82.161(a)(5)), but no such requirement exists now.

Source: EPA: Certification Requirements; 40 CFR 82.161(a)(5)

Why the other answers are wrong

  • Every two years with a retest — There is no two-year renewal cycle.
  • Every five years with a retest — There is no five-year renewal cycle.
  • Every ten years with a retest — There is no ten-year renewal cycle.

This question on its own page

45. An uncertified helper may recover refrigerant on a job only if what is true?
  • The helper is a registered, closely supervised apprenticeCorrect answer
  • The helper has already passed the Core section of the exam
  • The helper works only on systems holding under 50 pounds
  • The customer has agreed to it in writing beforehand

Why “The helper is a registered, closely supervised apprentice” is correct

40 CFR 82.161(a)(2) exempts apprentices who are closely and continually supervised by a certified technician. An apprentice must be registered with the Department of Labor's Office of Apprenticeship, and may be an apprentice for only two years from first registering.

Source: 40 CFR 82.161(a)(2); 40 CFR 82.152

Why the other answers are wrong

  • The helper has already passed the Core section of the exam — Passing Core alone does not certify a person for any equipment type.
  • The helper works only on systems holding under 50 pounds — Charge size does not create an exemption from certification.
  • The customer has agreed to it in writing beforehand — Customer consent does not replace certification.

This question on its own page

46. Each Section 608 certification test includes how many Core questions, and what is the passing score for a closed-book section?
  • 25 questions; 70 percentCorrect answer
  • 50 questions; 70 percent
  • 25 questions; 84 percent
  • 20 questions; 75 percent

Why “25 questions; 70 percent” is correct

Appendix D to Subpart F requires 25 questions from the Core group plus 25 from each technical group being tested. The passing score for closed-book tests is 70 percent; mail-in Type I tests need 84 percent.

Source: 40 CFR Part 82, Subpart F, Appendix D

Why the other answers are wrong

  • 50 questions; 70 percent — Core has 25 questions, not 50.
  • 25 questions; 84 percent — 84 percent applies only to the mail-in Type I test.
  • 20 questions; 75 percent — Neither 20 questions nor 75 percent appears in the test standards.

This question on its own page

47. A technician passed the Core section as an open-book exam. Can that score be used toward Universal certification?
  • Yes, any passing Core score counts
  • Yes, if Types I, II and III are passed within a year
  • No, Universal requires closed-book, proctored testingCorrect answer
  • No, Universal requires retaking Type I by mail

Why “No, Universal requires closed-book, proctored testing” is correct

Universal certification requires passing all sections under closed-book, secure, proctored conditions. EPA states that open-book Core tests cannot be used to get Universal, and Appendix D says mail-in Type I tests cannot count toward it either.

Source: EPA: Certification Requirements; 40 CFR Part 82, Subpart F, Appendix D

Why the other answers are wrong

  • Yes, any passing Core score counts — An open-book Core score does not count toward Universal.
  • Yes, if Types I, II and III are passed within a year — There is no time-window rule that turns an open-book score into a valid one.
  • No, Universal requires retaking Type I by mail — Mail-in Type I tests cannot be used toward Universal.

This question on its own page

48. Who issues the Section 608 technician certification card?
  • The EPA regional office
  • The approved organization that gave the testCorrect answer
  • The technician's employer
  • The state contractor licensing board

Why “The approved organization that gave the test” is correct

EPA does not give the test or issue cards. Approved technician certification programs administer the test and must issue a wallet-sized card within 30 days of the test (Appendix D, section f). A lost card is replaced by the organization that certified the technician.

Source: EPA: Section 608 Q&A; 40 CFR Part 82, Subpart F, Appendix D

Why the other answers are wrong

  • The EPA regional office — EPA approves the programs but does not issue cards.
  • The technician's employer — Employers can keep records but cannot certify technicians.
  • The state contractor licensing board — State boards are separate from the federal Section 608 program.

This question on its own page

49. Which person is not required to hold Section 608 certification?
  • Someone connecting gauges to a chiller
  • Someone recovering R-22 from a 10-ton rooftop unit for a repair
  • Someone adding refrigerant to a supermarket rack
  • Someone recovering from a household refrigerator for disposalCorrect answer

Why “Someone recovering from a household refrigerator for disposal” is correct

40 CFR 82.161(a)(1)(vii) says people who dispose of small appliances, MVACs and MVAC-like appliances do not need to be certified. Their recovery equipment must still meet the same performance standards as service equipment.

Source: 40 CFR 82.161(a)(1); EPA: Safe Disposal Requirements

Why the other answers are wrong

  • Someone connecting gauges to a chiller — Connecting gauges is listed as an activity that requires certification.
  • Someone recovering R-22 from a 10-ton rooftop unit for a repair — Recovering from a rooftop unit is Type II work that requires certification.
  • Someone adding refrigerant to a supermarket rack — Adding refrigerant to any covered appliance requires certification.

This question on its own page

50. A technician recovers refrigerant to dispose of a 20-pound residential split system. Which record does 40 CFR 82.156(a)(3) require, and for how long?
  • No records are required for this size of system
  • A leak rate calculation, kept for one year
  • The customer's signature on the work order, kept for five years
  • Location, date and refrigerant type, kept three yearsCorrect answer

Why “Location, date and refrigerant type, kept three years” is correct

For disposal of appliances with more than 5 and less than 50 pounds of refrigerant, technicians must record the company name, appliance location, date of recovery and refrigerant type, plus monthly totals and transfers for reclamation or destruction. Records are kept for three years.

Source: 40 CFR 82.156(a)(3); EPA: Section 608 Q&A

Why the other answers are wrong

  • No records are required for this size of system — Disposal of a 5 to 50 pound appliance does require records.
  • A leak rate calculation, kept for one year — Leak rate records are tied to leak repair on larger appliances, not disposal of this unit.
  • The customer's signature on the work order, kept for five years — A customer signature is not the required record, and the period is three years.

This question on its own page

51. Under 40 CFR 82.161(a), which certification is needed to service a low-pressure centrifugal chiller?
  • Type I
  • Type II
  • Type IIICorrect answer
  • Section 609

Why “Type III” is correct

Type III certification covers maintaining, servicing, repairing or disposing of low-pressure appliances, such as chillers using R-123 or R-11. Universal certification also covers them.

Source: 40 CFR 82.161(a)(1)

Why the other answers are wrong

  • Type I — Type I covers small appliances.
  • Type II — Type II covers medium-, high- and very high-pressure appliances.
  • Section 609 — Section 609 covers motor vehicle air conditioners.

This question on its own page

52. What must a scrap recycler do before accepting a household freezer for final disposal?
  • Nothing; recyclers are not covered by Section 608
  • Recover the remaining refrigerant or get a signed statementCorrect answer
  • Accept only freezers that carry a "refrigerant removed" sticker
  • Report each freezer to the EPA regional office

Why “Recover the remaining refrigerant or get a signed statement” is correct

Under 40 CFR 82.155(b), the final processor of a small appliance must either recover the remaining refrigerant or verify, with a signed statement or contract, that it was properly recovered. EPA does not accept stickers as proof.

Source: 40 CFR 82.155(b); EPA: Safe Disposal Requirements

Why the other answers are wrong

  • Nothing; recyclers are not covered by Section 608 — Final processors such as scrap recyclers are named in the safe disposal rule.
  • Accept only freezers that carry a "refrigerant removed" sticker — EPA does not mandate or accept a sticker as verification.
  • Report each freezer to the EPA regional office — Per-appliance reports to the regional office are not required.

This question on its own page

Substitute refrigerants and oils

53. A customer wants to switch an R-22 system to a replacement refrigerant by just adding it to the existing system. Why is this a problem?
  • Replacement refrigerants are illegal to sell
  • Only the manufacturer may change the refrigerant
  • Replacement refrigerants always require a new compressor and coil
  • No true drop-in exists; a retrofit usually needs other changesCorrect answer

Why “No true drop-in exists; a retrofit usually needs other changes” is correct

No substitute behaves exactly like the refrigerant it replaces. A retrofit, defined in 40 CFR 82.152, may require changing lubricants, gaskets, filters, driers, valves, O-rings or components so the system is compatible with the new refrigerant. The old refrigerant must also be recovered first.

Source: 40 CFR 82.152; EPA: Test Topics

Why the other answers are wrong

  • Replacement refrigerants are illegal to sell — Substitute refrigerants are legal to sell to certified technicians.
  • Only the manufacturer may change the refrigerant — Certified technicians perform retrofits; it is not limited to manufacturers.
  • Replacement refrigerants always require a new compressor and coil — A retrofit may or may not need a new compressor; it depends on the system.

This question on its own page

54. Which lubricant is typically used with the HFC refrigerant R-134a in stationary equipment?
  • Mineral oil
  • Polyolester (ester) oilCorrect answer
  • Alkylbenzene
  • Ordinary motor oil

Why “Polyolester (ester) oil” is correct

HFCs such as R-134a and R-410A do not mix well with the mineral oils used with CFCs, so stationary systems use synthetic polyolester (POE, ester) lubricants. Always follow the compressor maker's oil specification.

Source: EPA: Test Topics

Why the other answers are wrong

  • Mineral oil — Mineral oil is not miscible with HFCs and will not return well to the compressor.
  • Alkylbenzene — Alkylbenzene is associated with HCFCs such as R-22.
  • Ordinary motor oil — Motor oil is never used in a refrigeration compressor.

This question on its own page

55. Alkylbenzene lubricant is most closely associated with which refrigerant family?
  • HCFCs such as R-22Correct answer
  • HFCs such as R-410A
  • Hydrocarbons such as R-290
  • HFOs such as R-1234yf

Why “HCFCs such as R-22” is correct

Alkylbenzene oils are commonly used with HCFC refrigerants such as R-22. HFC refrigerants generally need ester oils, because they are not compatible with many of the lubricants used with CFCs and HCFCs.

Source: EPA: Test Topics

Why the other answers are wrong

  • HFCs such as R-410A — R-410A systems normally use POE oil.
  • Hydrocarbons such as R-290 — Hydrocarbon systems use lubricants chosen by their manufacturers, not as the classic alkylbenzene pairing.
  • HFOs such as R-1234yf — HFO automotive systems typically use other synthetic oils.

This question on its own page

56. An R-12 system is being retrofitted to R-134a. Why must the lubricant usually be changed?
  • Mineral oil would raise the ozone depletion potential of R-134a
  • R-134a reacts with mineral oil to form chlorine
  • R-134a does not mix well with the mineral oil used with R-12Correct answer
  • R-134a requires no lubricant at all

Why “R-134a does not mix well with the mineral oil used with R-12” is correct

Many substitute refrigerants are incompatible with the lubricants used with CFCs and HCFCs. R-134a does not mix with mineral oil, so oil would not travel back to the compressor properly, which can starve it. A retrofit usually moves to an ester oil.

Source: EPA: Test Topics; 40 CFR 82.152

Why the other answers are wrong

  • Mineral oil would raise the ozone depletion potential of R-134a — Oil does not change a refrigerant's ODP.
  • R-134a reacts with mineral oil to form chlorine — R-134a has no chlorine and does not create chlorine with oil.
  • R-134a requires no lubricant at all — Every compressor needs lubrication.

This question on its own page

57. Why should a container of polyolester (POE) oil be kept tightly sealed until it is used?
  • The oil evaporates quickly at room temperature
  • The oil turns into a flammable gas when opened
  • The oil readily absorbs moisture from the airCorrect answer
  • The oil loses its color and can no longer be identified

Why “The oil readily absorbs moisture from the air” is correct

POE oil is hygroscopic: it pulls moisture out of the air. Moisture in the system can form acids and sludge, so POE should be kept sealed and added from a fresh, closed container.

Source: EPA: Test Topics

Why the other answers are wrong

  • The oil evaporates quickly at room temperature — POE oil does not evaporate readily.
  • The oil turns into a flammable gas when opened — Opening the container does not turn the oil into a gas.
  • The oil loses its color and can no longer be identified — Color change is not the reason for keeping it sealed.

This question on its own page

58. What is fractionation in a refrigerant blend?
  • The oil separating from the refrigerant in the crankcase
  • The blend's components leaking out at different ratesCorrect answer
  • The refrigerant freezing at the metering device
  • The blend breaking down into chlorine in sunlight

Why “The blend's components leaking out at different rates” is correct

Zeotropic blends are made of several refrigerants with different boiling points. When such a blend leaks, the components can escape at different rates, changing the composition of what is left in the system. That change is called fractionation.

Source: EPA: Test Topics

Why the other answers are wrong

  • The oil separating from the refrigerant in the crankcase — Oil separation is a different issue from blend composition.
  • The refrigerant freezing at the metering device — Freezing at the metering device is a moisture problem.
  • The blend breaking down into chlorine in sunlight — Blends of HFCs contain no chlorine to release.

This question on its own page

59. How should a zeotropic blend such as R-407C be charged into a system to keep its composition correct?
  • As liquid from the cylinderCorrect answer
  • As vapor from the top of the cylinder
  • As vapor, with the cylinder warmed first
  • Alternating vapor and liquid in small amounts

Why “As liquid from the cylinder” is correct

Because the components of a zeotropic blend boil at different temperatures, drawing vapor off the top of the cylinder pulls more of the lighter components and shifts the mix. Removing it from the cylinder as liquid keeps the blend at its designed composition.

Source: EPA: Test Topics

Why the other answers are wrong

  • As vapor from the top of the cylinder — Vapor charging a zeotrope changes the composition through fractionation.
  • As vapor, with the cylinder warmed first — Warming the cylinder does not stop vapor from fractionating.
  • Alternating vapor and liquid in small amounts — Any vapor drawn from the cylinder can shift the mix.

This question on its own page

60. Which statement about refrigerant blends is correct?
  • Blends may always be topped off after a leak without concern
  • Zeotropic blends never change composition when they leak
  • All blends have a single boiling point at a given pressure
  • Azeotropes behave much like a single refrigerantCorrect answer

Why “Azeotropes behave much like a single refrigerant” is correct

Azeotropic blends (the R-500 series) behave much like one refrigerant. Zeotropic blends (the R-400 series) have components that boil at different temperatures, so they show temperature glide and can fractionate when they leak.

Source: EPA: Test Topics

Why the other answers are wrong

  • Blends may always be topped off after a leak without concern — After a leak a zeotropic blend may have shifted, so topping off can leave the wrong mix.
  • Zeotropic blends never change composition when they leak — Zeotropic blends are the ones that can change composition when they leak.
  • All blends have a single boiling point at a given pressure — Zeotropic blends boil across a temperature range, not at one point.

This question on its own page

Refrigeration

61. In a vapor-compression system, where does the refrigerant absorb heat and produce cooling?
  • In the condenser
  • In the compressor
  • In the evaporatorCorrect answer
  • In the receiver

Why “In the evaporator” is correct

Low-pressure liquid refrigerant boils in the evaporator, absorbing heat from the air or water passing over it. That boiling is where cooling happens; the vapor then goes to the compressor.

Source: EPA: Test Topics

Why the other answers are wrong

  • In the condenser — The condenser rejects heat to the outdoors or to water.
  • In the compressor — The compressor raises pressure and temperature; it does not cool the space.
  • In the receiver — A receiver stores liquid refrigerant; it does not produce cooling.

This question on its own page

62. What leaves the compressor in a working refrigeration system?
  • High-pressure, high-temperature vaporCorrect answer
  • Low-pressure, low-temperature vapor
  • High-pressure liquid
  • Low-pressure liquid

Why “High-pressure, high-temperature vapor” is correct

The compressor takes in low-pressure vapor from the evaporator and squeezes it into high-pressure, high-temperature vapor. That hot gas goes to the condenser to give up heat.

Source: EPA: Test Topics

Why the other answers are wrong

  • Low-pressure, low-temperature vapor — Low-pressure vapor is what enters the compressor.
  • High-pressure liquid — Refrigerant becomes high-pressure liquid in the condenser, after the compressor.
  • Low-pressure liquid — Low-pressure liquid is found after the metering device.

This question on its own page

63. What happens to the refrigerant in the condenser?
  • It boils and absorbs heat from the room air
  • It gives up heat and condenses to a liquidCorrect answer
  • Its pressure drops sharply
  • It is filtered of moisture and acid

Why “It gives up heat and condenses to a liquid” is correct

Hot, high-pressure vapor from the compressor gives up heat in the condenser and condenses into high-pressure liquid. The liquid then travels to the metering device.

Source: EPA: Test Topics

Why the other answers are wrong

  • It boils and absorbs heat from the room air — Boiling and absorbing heat happen in the evaporator.
  • Its pressure drops sharply — The large pressure drop happens at the metering device.
  • It is filtered of moisture and acid — Filtering is the job of a filter-drier, not the condenser.

This question on its own page

64. What does the metering device (such as an expansion valve or capillary tube) do to the refrigerant?
  • Raises its pressure so it can condense
  • Turns vapor into liquid
  • Separates oil from the refrigerant
  • Lowers its pressure so it can boil in the evaporatorCorrect answer

Why “Lowers its pressure so it can boil in the evaporator” is correct

The metering device restricts flow between the high and low sides. High-pressure liquid passes through it and drops to a low pressure and temperature, so it can boil in the evaporator and absorb heat.

Source: EPA: Test Topics

Why the other answers are wrong

  • Raises its pressure so it can condense — Raising pressure is the compressor's job.
  • Turns vapor into liquid — Vapor turns to liquid in the condenser.
  • Separates oil from the refrigerant — Oil separation is done by an oil separator, not the metering device.

This question on its own page

65. In a normally running system, what is in the suction line between the evaporator and the compressor?
  • Low-pressure vaporCorrect answer
  • High-pressure vapor
  • High-pressure liquid
  • Low-pressure liquid only

Why “Low-pressure vapor” is correct

Refrigerant leaving the evaporator has boiled off and is a low-pressure vapor, usually slightly superheated, as it returns to the compressor. Liquid reaching the compressor can damage it.

Source: EPA: Test Topics

Why the other answers are wrong

  • High-pressure vapor — High-pressure vapor is in the discharge line after the compressor.
  • High-pressure liquid — High-pressure liquid is in the liquid line after the condenser.
  • Low-pressure liquid only — Liquid should have boiled off before leaving the evaporator.

This question on its own page

66. On a standard manifold gauge set, what color is the low-side (compound) gauge and hose?
  • Red
  • Yellow
  • BlueCorrect answer
  • Green

Why “Blue” is correct

By trade convention the low-side compound gauge and its hose are blue, the high-side gauge and hose are red, and the center utility hose, used for recovery, evacuation or charging, is yellow.

Source: EPA: Test Topics

Why the other answers are wrong

  • Red — Red marks the high side.
  • Yellow — Yellow is the center utility hose.
  • Green — Green is not part of the standard manifold color code.

This question on its own page

67. Why is the low-side gauge called a compound gauge?
  • It reads pressure and temperature of two refrigerants
  • It reads both pressure and vacuumCorrect answer
  • It combines a gauge with a sight glass
  • It can be used on either side of the system

Why “It reads both pressure and vacuum” is correct

A compound gauge reads positive pressure in psig and also vacuum below atmospheric pressure in inches of mercury. That lets the low side be read during normal operation and during recovery or evacuation.

Source: EPA: Test Topics

Why the other answers are wrong

  • It reads pressure and temperature of two refrigerants — Dual temperature scales do not make a gauge "compound".
  • It combines a gauge with a sight glass — A sight glass is a separate component.
  • It can be used on either side of the system — The low-side gauge is meant for the low side; the high-side gauge has a higher range.

This question on its own page

68. Which leak detection method finds where a leak is, rather than only showing that the system is losing refrigerant?
  • Watching the receiver level over time
  • A standing pressure decay test
  • Comparing readings against a charging chart
  • Bubble solution or an electronic detectorCorrect answer

Why “Bubble solution or an electronic detector” is correct

40 CFR 82.152 lists bubble tests, ultrasonic tests, gas-imaging cameras and leak detection devices as ways to locate leaks. Pressure decay tests, sight glass checks, receiver levels and charging charts show that a system is leaking but not where.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Watching the receiver level over time — A falling receiver level shows a loss but not its location.
  • A standing pressure decay test — Pressure decay shows a leak exists but does not find it.
  • Comparing readings against a charging chart — Charging charts help judge charge, not leak location.

This question on its own page

69. A technician adds fluorescent dye to a system and later scans the joints. What is used to find the leak?
  • A black (ultraviolet) lightCorrect answer
  • A halide torch flame
  • A micron gauge
  • A sight glass

Why “A black (ultraviolet) light” is correct

Fluorescent dye travels with the refrigerant and oil and collects where they escape. Under a black (ultraviolet) light the dye glows, showing the exact leak point. Like bubble solution and electronic detectors, it locates a leak rather than only showing that one exists.

Source: EPA: Test Topics

Why the other answers are wrong

  • A halide torch flame — A halide torch is an old flame-based detector and is not used to see dye.
  • A micron gauge — A micron gauge measures deep vacuum, not leak location.
  • A sight glass — A sight glass shows liquid flow, not the location of a leak.

This question on its own page

70. A cylinder holding both liquid and vapor R-134a sits in a 75 °F shop. What mainly determines the pressure inside it?
  • How full the cylinder is
  • The refrigerant's temperatureCorrect answer
  • The size of the cylinder
  • How long ago it was last filled

Why “The refrigerant's temperature” is correct

When liquid and vapor are both present, the refrigerant is saturated and its pressure is set by its temperature, not by how much is in the cylinder. A nearly empty cylinder and a full one at the same temperature show about the same pressure, which is why weight, not pressure, tells how full a cylinder is.

Source: EPA: Test Topics

Why the other answers are wrong

  • How full the cylinder is — As long as some liquid remains, the amount does not set the pressure.
  • The size of the cylinder — Cylinder size does not change saturation pressure.
  • How long ago it was last filled — Elapsed time matters only because the temperature may have changed.

This question on its own page

The three Rs

71. Under 40 CFR 82.152, what does it mean to recover refrigerant?
  • Clean it with filter-driers for reuse
  • Return it to the manufacturer for credit
  • Process it to AHRI 700-2016 and test each batch
  • Remove it and store it in an outside containerCorrect answer

Why “Remove it and store it in an outside container” is correct

To recover is to remove refrigerant in any condition from an appliance and store it in an external container, without necessarily testing or processing it. Recovery is the first step whether the refrigerant will be reused, recycled, reclaimed or destroyed.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Clean it with filter-driers for reuse — Cleaning with filter-driers is recycling.
  • Return it to the manufacturer for credit — Returning refrigerant for credit is a business transaction, not the definition.
  • Process it to AHRI 700-2016 and test each batch — Processing to AHRI 700-2016 with testing is reclamation.

This question on its own page

72. Which describes recycling refrigerant under the Section 608 definitions?
  • Storing it in a recovery cylinder without processing
  • Reprocessing it to new-product specifications and testing every batch
  • Cleaning it for reuse in the same owner's equipmentCorrect answer
  • Destroying it at an approved facility

Why “Cleaning it for reuse in the same owner's equipment” is correct

40 CFR 82.152 defines recycling as extracting refrigerant and cleaning it for reuse in equipment of the same owner, without meeting all reclamation requirements. Recycling typically uses oil separation and passes through replaceable core filter-driers to reduce moisture, acidity and particles.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Storing it in a recovery cylinder without processing — Removing and storing without processing is recovery.
  • Reprocessing it to new-product specifications and testing every batch — Meeting new-product specs and testing each batch is reclamation.
  • Destroying it at an approved facility — Destruction is a separate fate for refrigerant that cannot be reused.

This question on its own page

73. Which of the three Rs requires laboratory analysis to show the refrigerant meets AHRI Standard 700-2016?
  • Recover
  • ReclaimCorrect answer
  • Recycle
  • Retrofit

Why “Reclaim” is correct

To reclaim is to reprocess refrigerant to all applicable specifications in Appendix A of Subpart F, based on AHRI Standard 700-2016, and to verify it with the prescribed analytical methods. Only reclaimed refrigerant may be sold to a new owner.

Source: 40 CFR 82.152; 40 CFR 82.164(a)

Why the other answers are wrong

  • Recover — Recovery is removal and storage with no testing required.
  • Recycle — Recycling cleans refrigerant on site but does not require lab analysis.
  • Retrofit — Retrofit means converting an appliance to a different refrigerant.

This question on its own page

74. A technician runs recovered R-22 through a recycling machine on site. Where may that recycled refrigerant be used?
  • In equipment owned by the same owner it came fromCorrect answer
  • In any customer's equipment
  • Only after it is sold to a wholesaler
  • Nowhere until a reclaimer tests it

Why “In equipment owned by the same owner it came from” is correct

Recycled refrigerant has been cleaned but not certified to reclamation standards, so it may be reused in equipment of the same owner. If it is to go to a different owner, it must be reclaimed by a certified reclaimer first.

Source: 40 CFR 82.152; 40 CFR 82.156(h)

Why the other answers are wrong

  • In any customer's equipment — Putting it into a different owner's equipment would require reclamation.
  • Only after it is sold to a wholesaler — Used refrigerant cannot be sold for reuse unless it has been reclaimed.
  • Nowhere until a reclaimer tests it — Reuse within the same owner does not require reclamation testing.

This question on its own page

75. Under 40 CFR 82.164, which requirement applies to a certified refrigerant reclaimer?
  • It must return reclaimed refrigerant only to the original owner
  • It may release up to 5 percent of refrigerant during processing
  • It must test each batch against Appendix A specificationsCorrect answer
  • It must hold Type III technician certification

Why “It must test each batch against Appendix A specifications” is correct

Certified reclaimers must reprocess refrigerant to the Appendix A specifications (based on AHRI 700-2016), verify each batch by the prescribed analysis, release no more than 1.5 percent during reclamation, dispose of wastes properly and keep records and annual reports.

Source: 40 CFR 82.164(a)

Why the other answers are wrong

  • It must return reclaimed refrigerant only to the original owner — Reclaimed refrigerant may be sold to new owners; that is the point of reclamation.
  • It may release up to 5 percent of refrigerant during processing — The limit is 1.5 percent, not 5 percent.
  • It must hold Type III technician certification — Reclaimer certification is separate from technician certification.

This question on its own page

Recovery techniques

76. Why must a technician avoid putting two different refrigerants into the same recovery cylinder?
  • The recovery machine will be damaged and stop working for good
  • The cylinder will weigh too much to ship
  • Mixing always causes an explosion
  • The mixture may not be reclaimable and may need destroyingCorrect answer

Why “The mixture may not be reclaimable and may need destroying” is correct

Reclaimers can restore one refrigerant to specification, but a mixture often cannot be separated. Mixed refrigerant may have to be destroyed, which is costly and wastes refrigerant. Use a separate, labeled cylinder for each refrigerant.

Source: EPA: Test Topics

Why the other answers are wrong

  • The recovery machine will be damaged and stop working for good — Mixing contaminates the refrigerant; it does not necessarily ruin the machine.
  • The cylinder will weigh too much to ship — Weight is not the reason; the problem is contamination.
  • Mixing always causes an explosion — Mixing does not always cause an explosion; the issue is that the mix cannot be reclaimed.

This question on its own page

77. A technician must recover R-22 from a rooftop unit on a cold winter morning. How will the low temperature affect the job?
  • Faster, because the cold refrigerant is denser
  • The recovery machine cannot run below 50 °F
  • No change; temperature does not affect recovery
  • Slower, because refrigerant pressure is lowerCorrect answer

Why “Slower, because refrigerant pressure is lower” is correct

Refrigerant pressure falls as temperature falls. In cold weather the pressure pushing refrigerant out of the system is lower, so recovery takes longer. Warm ambient conditions speed recovery.

Source: EPA: Test Topics

Why the other answers are wrong

  • Faster, because the cold refrigerant is denser — Lower pressure, not density, governs how fast vapor moves; cold slows recovery.
  • The recovery machine cannot run below 50 °F — There is no general rule that machines cannot run below 50 °F; follow the maker's limits.
  • No change; temperature does not affect recovery — Ambient temperature is one of the main factors in recovery speed.

This question on its own page

78. Which hose setup will usually give the fastest recovery?
  • Short hoses with a large inside diameterCorrect answer
  • Long hoses with a small inside diameter
  • Long hoses with a large inside diameter
  • Short hoses with valve-core depressors left in

Why “Short hoses with a large inside diameter” is correct

Hose length and diameter limit flow. Short hoses with a large inside diameter have the least restriction, so refrigerant moves to the recovery unit faster. Long, narrow hoses and restrictions such as valve cores slow the job.

Source: EPA: Test Topics

Why the other answers are wrong

  • Long hoses with a small inside diameter — Long, narrow hoses add the most restriction.
  • Long hoses with a large inside diameter — Extra length adds restriction even with a larger diameter.
  • Short hoses with valve-core depressors left in — Valve cores and depressors are restrictions that slow recovery.

This question on its own page

79. A technician removes the Schrader valve cores from the service ports with a core removal tool before recovering. Why?
  • To keep moisture out of the recovery unit
  • To reduce restriction and speed recoveryCorrect answer
  • To prevent the refrigerant from fractionating
  • To allow the system to be vented safely

Why “To reduce restriction and speed recovery” is correct

Schrader cores and the depressors that open them are small restrictions in the flow path. Removing the cores with a core removal tool, which keeps the system sealed, lets refrigerant flow more freely and shortens recovery time.

Source: EPA: Test Topics

Why the other answers are wrong

  • To keep moisture out of the recovery unit — Removing cores does not stop moisture; it speeds flow.
  • To prevent the refrigerant from fractionating — Fractionation depends on the blend and how it leaks, not on valve cores.
  • To allow the system to be vented safely — The system must never be vented; the tool keeps it sealed.

This question on its own page

80. Besides temperature and hoses, which factor has a large effect on how fast refrigerant can be recovered?
  • The color of the recovery cylinder
  • The brand of refrigerant in the system
  • The size and capacity of the recovery equipmentCorrect answer
  • The time of day the job is done

Why “The size and capacity of the recovery equipment” is correct

The size and capacity of the recovery or recycling machine affect how quickly refrigerant can be removed, along with ambient temperature and the length and diameter of hoses.

Source: EPA: Test Topics

Why the other answers are wrong

  • The color of the recovery cylinder — Cylinder color identifies the cylinder type, not recovery speed.
  • The brand of refrigerant in the system — The brand of a given refrigerant does not affect recovery rate.
  • The time of day the job is done — Time of day matters only through ambient temperature.

This question on its own page

81. The operating instructions for a certified recovery machine conflict with nothing in the Section 608 rules. How must the technician use the machine?
  • However the technician prefers
  • Only with the factory hoses removed
  • According to the manufacturer's directionsCorrect answer
  • Only after it has been recertified that year

Why “According to the manufacturer's directions” is correct

40 CFR 82.156(g) requires all recovery and recycling equipment to be used according to the manufacturer's directions unless those directions conflict with the rule. Using it correctly is how the technician reaches the required recovery levels.

Source: 40 CFR 82.156(g)

Why the other answers are wrong

  • However the technician prefers — The rule requires following the manufacturer's directions.
  • Only with the factory hoses removed — No rule calls for removing the hoses.
  • Only after it has been recertified that year — Technicians do not have to recertify machines each year.

This question on its own page

Dehydration and evacuation

82. After a repair, why is a system evacuated with a vacuum pump before it is charged?
  • To cool the compressor before startup
  • To remove air and moisture from the systemCorrect answer
  • To measure how much refrigerant leaked out
  • To mix the new oil with the refrigerant

Why “To remove air and moisture from the system” is correct

Evacuation removes air (non-condensables) and moisture that entered while the system was open. Leaving them in causes high pressures, poor cooling, acid and sludge, so the system is evacuated before refrigerant is added.

Source: EPA: Test Topics

Why the other answers are wrong

  • To cool the compressor before startup — Evacuation is not a cooling step for the compressor.
  • To measure how much refrigerant leaked out — Leak amount is measured by recovery weight or charge records, not by evacuation.
  • To mix the new oil with the refrigerant — Oil and refrigerant mix in operation; evacuation is about removing contaminants.

This question on its own page

83. Why does pulling a deep vacuum help remove water from a system?
  • It turns water into a non-condensable gas
  • It freezes the water so it can be drained out later
  • It pushes water into the compressor oil
  • It lowers water's boiling point so it boils offCorrect answer

Why “It lowers water's boiling point so it boils off” is correct

The lower the pressure, the lower the temperature at which water boils. In a deep vacuum, moisture inside the system boils off at ordinary temperatures and the vacuum pump draws out the vapor.

Source: EPA: Test Topics

Why the other answers are wrong

  • It turns water into a non-condensable gas — Water vapor is condensable; it is removed as vapor, not changed into air.
  • It freezes the water so it can be drained out later — Freezing would trap water rather than remove it; good practice avoids it.
  • It pushes water into the compressor oil — Moving water into the oil would contaminate it, not remove it.

This question on its own page

84. What problem can moisture left in a system cause?
  • Acids and sludge, and ice at the metering deviceCorrect answer
  • Lower head pressure and better efficiency
  • Faster oil return to the compressor
  • Higher ozone depletion potential of the refrigerant

Why “Acids and sludge, and ice at the metering device” is correct

Moisture reacts with refrigerant and oil to form acids and sludge that damage compressors and motor windings. It can also freeze at the metering device and block flow. Evacuation removes it.

Source: EPA: Test Topics

Why the other answers are wrong

  • Lower head pressure and better efficiency — Moisture harms performance; it does not improve it.
  • Faster oil return to the compressor — Moisture does not help oil return.
  • Higher ozone depletion potential of the refrigerant — Moisture does not change a refrigerant's ODP.

This question on its own page

85. Air left in a system after service is a non-condensable. What is a likely result?
  • Lower discharge temperature
  • Higher than normal head pressureCorrect answer
  • Better heat transfer in the condenser
  • A rise in the refrigerant's boiling point in the evaporator only

Why “Higher than normal head pressure” is correct

Air does not condense at system conditions. It collects in the condenser, takes up space needed for condensing and raises head pressure, which reduces capacity and puts extra load on the compressor.

Source: EPA: Test Topics

Why the other answers are wrong

  • Lower discharge temperature — Non-condensables tend to raise, not lower, discharge temperature.
  • Better heat transfer in the condenser — Air in the condenser reduces heat transfer.
  • A rise in the refrigerant's boiling point in the evaporator only — The main effect is on the high side, where air collects.

This question on its own page

86. Which instrument is used to confirm that a deep vacuum has been reached during dehydration?
  • A sight glass
  • A refrigerant scale
  • A micron gaugeCorrect answer
  • An ammeter

Why “A micron gauge” is correct

A micron gauge reads very low absolute pressures, far below what a compound gauge can show accurately. It tells the technician when the vacuum is deep enough and whether pressure rises after the pump is isolated.

Source: EPA: Test Topics

Why the other answers are wrong

  • A sight glass — A sight glass shows liquid flow during operation.
  • A refrigerant scale — A scale weighs refrigerant; it does not measure vacuum.
  • An ammeter — An ammeter measures electrical current.

This question on its own page

Safety

87. A large R-22 leak occurs in a basement equipment room. What is the main breathing hazard?
  • R-22 vapor has a strong odor that causes vomiting
  • The vapor is lighter than air and rises to the ceiling
  • R-22 vapor is highly flammable
  • Vapor displaces oxygen and can cause suffocationCorrect answer

Why “Vapor displaces oxygen and can cause suffocation” is correct

Refrigerant vapors are heavier than air and collect in low, enclosed spaces such as basements and pits, pushing out oxygen. Breathing that air can cause oxygen deprivation and suffocation without warning.

Source: EPA: Test Topics

Why the other answers are wrong

  • R-22 vapor has a strong odor that causes vomiting — Most refrigerants have little odor, so there may be no warning at all.
  • The vapor is lighter than air and rises to the ceiling — Common refrigerant vapors are heavier than air and settle low.
  • R-22 vapor is highly flammable — R-22 is not classed as flammable.

This question on its own page

88. Besides oxygen deprivation, what health effect can result from breathing high concentrations of refrigerant vapor?
  • Irregular heartbeat (cardiac effects)Correct answer
  • Permanent color blindness
  • Improved alertness
  • Hearing loss

Why “Irregular heartbeat (cardiac effects)” is correct

High concentrations of refrigerant vapor can sensitize the heart and cause an irregular heartbeat, which can be fatal. This is one reason refrigerant releases in enclosed spaces are dangerous even before oxygen runs low.

Source: EPA: Test Topics

Why the other answers are wrong

  • Permanent color blindness — Color blindness is not a known effect of refrigerant exposure.
  • Improved alertness — Refrigerant exposure dulls, rather than sharpens, alertness.
  • Hearing loss — Hearing loss is not linked to breathing refrigerant.

This question on its own page

89. Why should a technician wear gloves and goggles when connecting hoses to a system?
  • Liquid refrigerant can freeze skin and eyesCorrect answer
  • Refrigerant stains skin permanently
  • Gloves keep refrigerant from becoming contaminated
  • The rules require them only for flammable refrigerants

Why “Liquid refrigerant can freeze skin and eyes” is correct

Liquid refrigerant boils at very low temperatures once released, so a spray on skin or eyes can freeze tissue and cause frostbite or eye injury. Gloves and goggles (or safety glasses with side shields) protect against this.

Source: EPA: Test Topics

Why the other answers are wrong

  • Refrigerant stains skin permanently — Refrigerant does not stain skin; the hazard is freezing.
  • Gloves keep refrigerant from becoming contaminated — Gloves protect the technician, not the refrigerant.
  • The rules require them only for flammable refrigerants — Frostbite risk exists with all refrigerants, flammable or not.

This question on its own page

90. A large refrigerant leak has filled an enclosed machinery room. What protection is needed to enter it?
  • A paper dust mask over the nose and mouth
  • A self-contained breathing apparatusCorrect answer
  • Safety glasses only
  • Ear protection

Why “A self-contained breathing apparatus” is correct

In extreme cases, such as a large leak in a closed space where oxygen may be low, a self-contained breathing apparatus is needed because it supplies its own air. Filter masks do not supply oxygen.

Source: EPA: Test Topics

Why the other answers are wrong

  • A paper dust mask over the nose and mouth — A dust mask filters particles but supplies no oxygen.
  • Safety glasses only — Eye protection does nothing for an oxygen-poor atmosphere.
  • Ear protection — Ear protection does not address breathing hazards.

This question on its own page

91. How is a refillable refrigerant recovery cylinder usually identified by color?
  • The color of the refrigerant it holds
  • Solid green
  • Red body with a white top
  • Gray body with a yellow topCorrect answer

Why “Gray body with a yellow top” is correct

Recovery cylinders are commonly painted with a gray body and a yellow top (shoulder). They must be DOT-approved for refilling. Disposable cylinders of new refrigerant are color-coded by refrigerant type instead.

Source: EPA: Test Topics

Why the other answers are wrong

  • The color of the refrigerant it holds — Refrigerant-specific colors are used on new-refrigerant cylinders, not recovery cylinders.
  • Solid green — Solid green is not the recovery cylinder color code.
  • Red body with a white top — Red with a white top is not the recovery cylinder color code.

This question on its own page

92. A disposable cylinder of R-410A is empty. What should the technician never do with it?
  • Mark it as empty
  • Recover the remaining vapor from it
  • Refill it with recovered refrigerantCorrect answer
  • Take it to a metal recycler once it is emptied

Why “Refill it with recovered refrigerant” is correct

Disposable cylinders are not built or approved for refilling. Refilling one can lead to a rupture. Recovered refrigerant goes only into DOT-approved refillable recovery cylinders.

Source: EPA: Test Topics; 40 CFR 84.116

Why the other answers are wrong

  • Mark it as empty — Marking it empty is a reasonable step before disposal.
  • Recover the remaining vapor from it — Recovering the heel from a disposable cylinder is the correct practice.
  • Take it to a metal recycler once it is emptied — Once its heel has been recovered, an empty disposable cylinder can go for scrap; for HFC cylinders, 40 CFR 84.116 adds heel-removal paperwork from 2028.

This question on its own page

93. Why must a recovery cylinder never be filled to more than 80 percent of its capacity?
  • The recovery machine cannot push refrigerant above 80 percent
  • Warming liquid expands and could burst the cylinderCorrect answer
  • Refrigerant above 80 percent turns to vapor and vents
  • DOT allows only 80 percent so the cylinder weighs less

Why “Warming liquid expands and could burst the cylinder” is correct

As temperature rises, liquid refrigerant expands. A cylinder that is too full can become completely liquid-filled, and further warming then builds pressure very quickly and can rupture it. Leaving at least 20 percent vapor space prevents this.

Source: EPA: Test Topics

Why the other answers are wrong

  • The recovery machine cannot push refrigerant above 80 percent — The limit is about cylinder safety, not machine capacity.
  • Refrigerant above 80 percent turns to vapor and vents — Refrigerant above 80 percent does not simply vent; the danger is hydrostatic pressure.
  • DOT allows only 80 percent so the cylinder weighs less — The limit protects against rupture, not shipping weight.

This question on its own page

94. Which gas should be used to pressurize a system for leak testing?
  • Oxygen
  • Compressed shop air
  • Acetylene
  • Dry nitrogenCorrect answer

Why “Dry nitrogen” is correct

Dry nitrogen is inert and contains no moisture, so it is the gas used for pressure testing. Oxygen or compressed air mixed with compressor oil under pressure can explode, and shop air adds moisture.

Source: EPA: Test Topics

Why the other answers are wrong

  • Oxygen — Oxygen with oil under pressure can explode.
  • Compressed shop air — Shop air contains oxygen and moisture; under pressure with oil it can also explode.
  • Acetylene — Acetylene is a fuel gas and highly flammable.

This question on its own page

95. When pressurizing a system with nitrogen for a leak test, what equipment must be used with the nitrogen cylinder?
  • A vacuum pump and a micron gauge
  • A recovery machine and a scale
  • A pressure regulator and a relief valveCorrect answer
  • A sight glass and a filter-drier

Why “A pressure regulator and a relief valve” is correct

A full nitrogen cylinder can be above 2,000 psig, far more than a system can safely hold. A pressure regulator reduces it to the test pressure, and a relief valve in the line protects the system if the regulator fails.

Source: EPA: Test Topics

Why the other answers are wrong

  • A vacuum pump and a micron gauge — A vacuum pump and micron gauge are for evacuation, not pressurizing.
  • A recovery machine and a scale — Recovery machines and scales are for removing and weighing refrigerant.
  • A sight glass and a filter-drier — A sight glass and drier are system parts, not nitrogen safety devices.

This question on its own page

96. Where should a technician look to learn the exposure hazards of a particular refrigerant?
  • The refrigerant's safety data sheet (SDS)Correct answer
  • The appliance nameplate
  • The recovery machine's certification label
  • The pressure-temperature chart

Why “The refrigerant's safety data sheet (SDS)” is correct

The safety data sheet lists the refrigerant's health hazards, exposure limits, first aid and protective equipment. Reading it is part of understanding short-term and long-term exposure risks.

Source: EPA: Test Topics

Why the other answers are wrong

  • The appliance nameplate — The nameplate gives refrigerant type and charge, not health hazards.
  • The recovery machine's certification label — The certification label confirms machine testing, not refrigerant hazards.
  • The pressure-temperature chart — A P-T chart gives pressures and temperatures, not exposure information.

This question on its own page

Shipping

97. A cylinder of recovered R-22 is being shipped to a reclaimer. What must its labels show?
  • The name of the appliance owner
  • Refrigerant name and DOT hazard class tagCorrect answer
  • The date the system was installed
  • The price paid for the refrigerant

Why “Refrigerant name and DOT hazard class tag” is correct

Cylinders being shipped must be labeled with the refrigerant they contain and carry the Department of Transportation classification tag for the hazard class. This tells handlers and the reclaimer what is inside.

Source: EPA: Test Topics

Why the other answers are wrong

  • The name of the appliance owner — The owner's name is not a required cylinder label.
  • The date the system was installed — Installation date has nothing to do with shipping labels.
  • The price paid for the refrigerant — Price is not a labeling requirement.

This question on its own page

98. Which DOT hazard classification applies to cylinders of common refrigerants such as R-22 or R-134a?
  • Corrosive material
  • Flammable liquid
  • Nonflammable gasCorrect answer
  • Poison gas

Why “Nonflammable gas” is correct

Common A1 refrigerants such as R-22, R-134a and R-410A ship under the DOT nonflammable gas classification (Division 2.2). The cylinder must carry that classification tag along with the refrigerant name.

Source: EPA: Test Topics

Why the other answers are wrong

  • Corrosive material — They are not shipped as corrosives.
  • Flammable liquid — These refrigerants are shipped as compressed gases, not flammable liquids.
  • Poison gas — They are not classed as poison gases.

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99. Which type of container may be used to ship recovered refrigerant to a reclaimer?
  • A DOT-approved refillable recovery cylinderCorrect answer
  • An empty disposable cylinder the refrigerant came in
  • Any steel tank with a working valve
  • A plastic jug with a sealed cap

Why “A DOT-approved refillable recovery cylinder” is correct

Recovered refrigerant must go into, and be shipped in, DOT-approved refillable recovery cylinders. Disposable cylinders must never be refilled, and other containers are not rated to hold refrigerant pressure.

Source: EPA: Test Topics

Why the other answers are wrong

  • An empty disposable cylinder the refrigerant came in — Disposable cylinders must not be refilled.
  • Any steel tank with a working valve — A tank must be approved for refrigerant service, not just have a valve.
  • A plastic jug with a sealed cap — Plastic containers cannot hold refrigerant under pressure.

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100. A technician has a cylinder holding a mix of R-22 and R-404A. How should it be labeled before shipment to a reclaimer?
  • With no refrigerant name, only the DOT tag
  • As R-22, since R-22 was put in first
  • As R-404A, since it is the larger amount
  • As mixed refrigerant, naming what it containsCorrect answer

Why “As mixed refrigerant, naming what it contains” is correct

Labels must correctly identify what is in the cylinder. A mixture must be identified as such so the reclaimer can handle it properly; mixed refrigerant may not be reclaimable and may have to be destroyed.

Source: EPA: Test Topics

Why the other answers are wrong

  • With no refrigerant name, only the DOT tag — Refrigerant identification is required in addition to the DOT tag.
  • As R-22, since R-22 was put in first — Labeling a mixture as one refrigerant is inaccurate and can contaminate other product.
  • As R-404A, since it is the larger amount — Labeling by the larger amount still misstates the contents.

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More EPA 608 practice

Read next

  • Refrigerant Types: CFC, HCFC, HFC, HFO and Natural Refrigerants: The Section 608 exam expects you to know which family a refrigerant belongs to, what that means for the ozone layer, and which pressure class it falls in. This guide covers the main refrigerant families, the pressure classes defined in the regulation, blends and fractionation, oils, and a short note on A2L refrigerants.
  • EPA Refrigerant Recovery Rules: Most of what Section 608 asks of technicians comes down to one idea: get the refrigerant out and into a container instead of the air. This guide covers the venting prohibition, the required evacuation levels, small-appliance recovery, recovery equipment rules, the three Rs, safe disposal and the sales restriction, with the regulation cited for each.
  • EPA 608 Study Guide: Core, Type I, Type II and Type III: EPA does not publish a study guide for the Section 608 exam. It publishes a list of test topics. This guide works through that list section by section, explains what each topic is about, and gives the numbers from the regulation you need to know.

Unofficial, not affiliated with the EPA or any EPA-approved certifying organization. Questions are original practice written from public EPA material, not real exam questions.