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EPA 608 Type 2 practice test

Printable version. Original practice questions written from EPA's published rules, not questions from the real exam. The answer key, with an explanation for every answer, is at the end.

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Questions

Leak detection

1. An R-410A split system is cooling poorly, and the technician measures excessive superheat at the evaporator outlet. What does this most likely point to?

  1. A An overcharge of refrigerant
  2. B A dirty condenser coil
  3. C A leak that has left it undercharged
  4. D Too much airflow over the condenser

2. While inspecting a hermetic R-22 system, a technician finds an oily film around a brazed joint on the suction line. Why is this worth checking with a leak detector?

  1. A Oil residue at a joint is a common sign of a refrigerant leak
  2. B It shows the compressor has too much oil
  3. C It means the joint was overheated when it was brazed at the factory
  4. D It shows moisture has entered the system

3. A technician has just replaced a leaking evaporator coil on an R-22 system. What should be done before the system is recharged?

  1. A Run the compressor briefly to check rotation
  2. B Leak test the system
  3. C Add a small amount of oil
  4. D Charge it by sight glass

4. Which gas does EPA's test outline list as the best choice for pressurizing a high-pressure system for a leak test?

  1. A Pure R-22
  2. B Compressed air
  3. C Oxygen
  4. D Nitrogen alone

5. Rank these leak test gases from most to least preferred, following EPA's test outline.

  1. A Pure refrigerant, nitrogen with trace R-22, nitrogen alone
  2. B Nitrogen with trace R-22, nitrogen alone, pure refrigerant
  3. C Nitrogen alone, nitrogen with trace R-22, pure refrigerant
  4. D Nitrogen alone, pure refrigerant, nitrogen with trace R-22

6. Why might a technician add a trace amount of R-22 to the nitrogen used to pressure test a system?

  1. A So an electronic leak detector can sense the escaping gas
  2. B To lubricate the compressor during the test
  3. C To raise the test pressure without using any more nitrogen
  4. D To dry out moisture inside the system

7. Why is pressurizing a system with pure refrigerant the least preferred way to leak test it?

  1. A Refrigerant cannot reach a high enough pressure
  2. B Refrigerant reacts with brazed joints
  3. C Electronic detectors cannot sense a pure refrigerant charge
  4. D Refrigerant is released when the test gas is let out

8. A sight glass check and a standing pressure test both show that a 200-pound R-22 system is leaking. Under the Part 82 definition of leak inspection, what else is required?

  1. A Nothing; either check alone is a complete leak inspection
  2. B A method that finds the leak's location
  3. C A refrigerant analysis by a reclaimer
  4. D A second standing pressure test a week later

9. Who must perform the leak inspection required on a 150-pound R-22 comfort-cooling chiller that has exceeded its trigger rate?

  1. A The building owner
  2. B Any maintenance employee
  3. C A certified technician
  4. D An EPA inspector

10. A cold storage warehouse system holds 600 pounds of R-22 and has exceeded the 20 percent leak rate. How often must it receive leak inspections?

  1. A Once a year until it stays under the rate for one year
  2. B Once a month until the leak is repaired
  3. C Only once, after the repair
  4. D Every three months until four clean quarters in a row

11. During a required leak inspection of a 300-pound R-22 commercial system, which components may the technician skip?

  1. A Components more than two meters above a support surface
  2. B Any component behind an access panel
  3. C Components on the high side
  4. D Components installed more than ten years before the inspection

12. An automatic leak detection system that senses refrigerant in the air replaces quarterly inspections on a 900-pound R-22 system indoors. What must it be able to do?

  1. A Detect 100 ppm and alarm at 1,000 ppm
  2. B Detect 10 ppm and alert the owner at 100 ppm
  3. C Detect 50 ppm and automatically shut down the compressor
  4. D Detect 1 ppm and notify EPA directly

Leak repair requirements

13. A supermarket display case system holds 80 pounds of R-22. Under 40 CFR Part 82, above what annual leak rate must the owner repair it?

  1. A 10 percent
  2. B 20 percent
  3. C 30 percent
  4. D 35 percent

14. A chemical plant's process cooling system holds 600 pounds of R-22. What trigger leak rate applies to it under 40 CFR Part 82?

  1. A 10 percent
  2. B 20 percent
  3. C 35 percent
  4. D 30 percent

15. An office building's comfort-cooling chiller holds 150 pounds of R-22. Under 40 CFR Part 82, above what annual leak rate must leaks be repaired?

  1. A 10 percent
  2. B 15 percent
  3. C 20 percent
  4. D 30 percent

16. A rooftop unit holds 100 pounds of R-410A, an HFC. Does the Part 82 leak repair section, 40 CFR 82.157, apply to it?

  1. A Yes, because it holds more than 50 pounds
  2. B Yes, at the 20 percent commercial rate
  3. C No, it covers only ozone-depleting refrigerants
  4. D No, because rooftop units are exempt from all leak rules

17. A commercial split system holds 40 pounds of R-22 and is leaking 25 percent a year. Is the owner subject to the Part 82 leak repair requirements?

  1. A Yes, the comfort cooling rate is 10 percent
  2. B No, the appliance holds less than 50 pounds
  3. C Yes, any HCFC leak must be repaired within 30 days
  4. D No, because R-22 is no longer produced

18. A 200-pound R-22 comfort-cooling chiller is found leaking above its trigger rate. Unless an exception applies, how long does the owner have to repair the leaks?

  1. A 10 days
  2. B 30 days
  3. C 120 days
  4. D One year

19. Repairing a leak on a 700-pound R-22 industrial process system requires shutting down the process it serves. How long does the owner have to complete the repair?

  1. A 30 days
  2. B 180 days
  3. C 120 days
  4. D 270 days

20. A leak on a 300-pound R-22 chiller was repaired after the system was evacuated. When must the initial verification test be done?

  1. A Within 10 days after the chiller returns to normal operation
  2. B Before any refrigerant is added back to the chiller
  3. C Only after the full charge has been restored
  4. D At the next annual leak inspection

21. A leak on a 90-pound R-22 commercial refrigeration system passed its initial verification test without the system being evacuated. When must the follow-up verification test be performed?

  1. A Within 30 days of the successful initial test
  2. B Within 10 days of the successful initial test
  3. C Before the next refrigerant addition
  4. D Within 12 months of the repair

22. A replacement compressor for a leaking 400-pound R-22 commercial system cannot be delivered within 30 days. If the extension rules are met, how much extra time is allowed?

  1. A Up to 30 days after delivery, but no more than 180 days in total
  2. B Up to 90 days after the parts arrive, with no overall time limit at all
  3. C An automatic extra year from the leak date
  4. D Up to 120 days, regardless of delivery date

23. The owner of a 250-pound R-22 chiller needs more than 30 days to finish repairs because parts are back-ordered. By when must the extension request reach EPA?

  1. A Within 30 days of the appliance exceeding the leak rate
  2. B Within 6 months of the leak
  3. C Before the next scheduled annual leak inspection of the system
  4. D By March 1 of the following year

24. The owner of a leaking 180-pound R-22 chiller decides to retire it rather than repair it. How soon must a retirement plan be created?

  1. A Within 10 days of the first refrigerant addition after the leak
  2. B Within 30 days of the appliance exceeding the leak rate
  3. C Within 6 months of the leak
  4. D Within one year of the leak

25. Unless granted extra time, how long does an owner have to complete the work in a retrofit or retirement plan for a leaking R-22 appliance of 50 pounds or more?

  1. A 30 days from the plan's date
  2. B Six months from the plan's date
  3. C One year from the plan's date
  4. D Two years from the plan's date

26. Which requirement applies to a retrofit or retirement plan for a leaking 300-pound R-22 commercial refrigeration system?

  1. A It must be signed by the technician who first found the leak
  2. B It must be mailed to EPA within 10 days
  3. C It must be filed with the state fire marshal
  4. D It must be signed by a company official and kept on site

27. After writing a retirement plan for a leaking 120-pound R-22 chiller, the owner finds the leak rate is now below 10 percent. Within what time of the plan's date must this be established to ask EPA for relief from retiring it?

  1. A 30 days
  2. B 90 days
  3. C 1 year
  4. D 180 days

28. A 200-pound R-22 appliance leaked 260 pounds of refrigerant during one calendar year. What must the owner do?

  1. A Submit a report to EPA by March 1 of the following year
  2. B Retire the appliance within 30 days
  3. C Notify the state within 10 days
  4. D Nothing more, as long as each individual leak was repaired

29. How long must records required under the Part 82 leak repair rules be kept, unless the rule says otherwise?

  1. A One year
  2. B Three years
  3. C Five years
  4. D For the life of the appliance

30. A contractor adds 12 pounds of R-22 to a customer's 150-pound chiller. What does 40 CFR 82.157 require the contractor to give the owner?

  1. A A copy of the technician's Section 608 certification wallet card
  2. B A new nameplate showing the charge
  3. C A signed retrofit plan
  4. D A record including the amount and type of refrigerant added

31. The owner of a 300-pound R-22 chiller must calculate the leak rate every time refrigerant is added, except when the addition:

  1. A is less than 5 pounds
  2. B is made by the owner's own technician
  3. C is made in the first month of the calendar year
  4. D follows a retrofit or is a seasonal variance

32. A 100-pound R-22 comfort-cooling system needed 10 pounds to return to full charge, and the last addition was 73 days ago. Using the annualizing method, what is the leak rate?

  1. A 10 percent
  2. B 20 percent
  3. C 50 percent
  4. D 73 percent

33. An owner mothballs a leaking 250-pound R-22 commercial refrigeration system by evacuating it and shutting it down. What happens to the repair deadlines?

  1. A They are suspended until refrigerant is added again
  2. B They are cancelled permanently
  3. C They keep running as normal
  4. D They are extended by exactly one year from the leak date

34. An office building's comfort-cooling chiller holds 300 pounds of R-134a, an HFC. Under the 40 CFR Part 84 leak repair rule that took effect January 1, 2026, what trigger leak rate applies?

  1. A 10 percent
  2. B 20 percent
  3. C 30 percent
  4. D No rate; HFC systems are not covered

Recovery techniques

35. When recovering R-22 from a 200-pound system, why is it best to remove liquid refrigerant first?

  1. A Liquid recovery moves refrigerant much faster than vapor
  2. B Liquid cannot be recovered after vapor
  3. C It keeps the oil in the system
  4. D It removes the need to reach the required recovery vacuum

36. A technician wants to recover liquid first from a 150-pound R-22 system with a receiver. Where is the liquid refrigerant normally found when the system is off?

  1. A In the suction line and accumulator only
  2. B In the receiver and liquid line
  3. C In the discharge line
  4. D In the compressor crankcase only

37. How does chilling the recovery cylinder speed up recovery from an R-410A system?

  1. A It thickens the oil so less is carried over
  2. B It lowers cylinder pressure, widening the pressure difference
  3. C It lets the cylinder be filled past 80 percent of its liquid capacity
  4. D It removes non-condensables from the refrigerant

38. Why can warming the appliance help when recovering R-22 from a cold rooftop unit in winter?

  1. A It raises the refrigerant pressure in the appliance
  2. B It lowers the boiling point of the oil
  3. C It makes the refrigerant easier to separate from air
  4. D It lets system-dependent equipment be used

39. Which step speeds recovery from a 100-pound R-407C system?

  1. A Heating the recovery cylinder
  2. B Using the longest, smallest hoses available
  3. C Chilling the recovery cylinder
  4. D Recovering vapor before liquid

40. A technician has finished recovering R-22 and next needs to recover R-410A with the same machine. What should be done first to prevent cross-contamination?

  1. A Run the machine on R-410A for a minute, then vent the hoses to air
  2. B Use the same recovery cylinder for both refrigerants
  3. C Add a small amount of POE oil to the machine
  4. D Clear the R-22 from the machine and hoses as the manual directs

41. Which practice keeps recovered refrigerants from being mixed?

  1. A Topping up a cylinder with whatever refrigerant is on hand
  2. B Labelling the cylinder after it is full
  3. C Combining partly full cylinders to save space
  4. D Using a separate recovery cylinder for each refrigerant

42. A shop accidentally recovers R-22 into a cylinder already partly filled with R-410A. What is the usual consequence?

  1. A The mixture can be reused as R-410A
  2. B The mixture becomes R-407C
  3. C The mixture may not be reclaimable and may need destruction
  4. D The R-22 simply settles out at the bottom and can be drawn off

43. Why should a technician wait a few minutes after reaching the required vacuum on an R-22 system before opening it?

  1. A To let the recovery machine cool down
  2. B To let the compressor oil drain back
  3. C To see if the pressure rises, showing refrigerant remains
  4. D To let any moisture boil out of the refrigerant before opening

44. After shutting off the recovery machine at the required vacuum, the gauge on an R-407C system climbs back toward 0 psig. What should the technician do?

  1. A Open the system right away
  2. B Vent the remaining vapor
  3. C Add nitrogen to push the vapor out, then open it
  4. D Resume recovery until the level holds

45. What usually causes the pressure to rise in an R-22 system that has just been pulled down to its recovery vacuum?

  1. A Refrigerant boiling out of the oil or remaining liquid
  2. B Air leaking into the system through the gauge set hoses
  3. C Heat from the recovery machine
  4. D A failed pressure gauge

46. In the push-pull method of liquid recovery from a large R-22 system, what does the recovery machine do?

  1. A It pumps liquid directly through its compressor
  2. B It moves vapor from the cylinder into the system to push liquid out
  3. C It heats the system so the liquid boils over into the recovery cylinder
  4. D It runs the system's own compressor to pump down

47. Which recovery machine is a technician required to use on a 300-pound R-410A system?

  1. A Any machine that reaches 10 inches of Hg
  2. B Any machine built before November 15, 1993, whatever its rating
  3. C A system-dependent unit
  4. D A machine certified for that refrigerant and type of appliance

48. Near the end of recovering vapor from an R-22 system, recovery slows down. Why?

  1. A The recovery cylinder is getting colder
  2. B Lower system pressure means thinner vapor, so less moves per stroke
  3. C The machine's filter-drier has clogged and stopped flow almost entirely
  4. D The oil is turning into vapor

Recovery requirements

49. A technician is replacing the compressor on a very high-pressure appliance that uses R-23, using recovery equipment manufactured in 2019. To what level must the appliance be evacuated before it is opened?

  1. A 0 inches of Hg vacuum
  2. B 4 inches of Hg vacuum
  3. C 10 inches of Hg vacuum
  4. D 15 inches of Hg vacuum

50. An appliance charged with R-508B is being sent for disposal. The only recovery machine on site was manufactured in 1991. What evacuation level does Table 1 require?

  1. A 4 inches of Hg vacuum
  2. B 0 inches of Hg vacuum
  3. C 10 inches of Hg vacuum
  4. D 25 mm Hg absolute

51. A packaged rooftop unit holds 150 pounds of R-22. Using recovery equipment made after November 15, 1993, to what level must it be evacuated before the condenser coil is replaced?

  1. A 4 inches of Hg vacuum
  2. B 10 inches of Hg vacuum
  3. C 0 inches of Hg vacuum
  4. D 15 inches of Hg vacuum

52. A technician recovers R-410A from a split system with a 12-pound charge using a recovery machine built in 1990. What evacuation level must be reached before opening the system for a major repair?

  1. A 10 inches of Hg vacuum
  2. B 4 inches of Hg vacuum
  3. C 25 mm Hg absolute
  4. D 0 inches of Hg vacuum

53. A process chiller holds 250 pounds of R-407C. Using recovery equipment manufactured in 2015, what evacuation level is required before a major repair?

  1. A 0 inches of Hg vacuum
  2. B 10 inches of Hg vacuum
  3. C 4 inches of Hg vacuum
  4. D 15 inches of Hg vacuum

54. A technician uses a recovery machine built in 1992 on an R-22 system with a 300-pound charge before replacing its evaporator. What level must be reached?

  1. A 10 inches of Hg vacuum
  2. B 0 inches of Hg vacuum
  3. C 4 inches of Hg vacuum
  4. D 15 inches of Hg vacuum

55. A walk-in cooler system holds 120 pounds of R-134a. Using recovery equipment made in 2010, what evacuation level is required before the compressor is removed?

  1. A 0 inches of Hg vacuum
  2. B 4 inches of Hg vacuum
  3. C 15 inches of Hg vacuum
  4. D 10 inches of Hg vacuum

56. An older R-12 system with an 80-pound charge is being opened to replace its condenser. The recovery unit was manufactured in 1989. What evacuation level does Table 1 require?

  1. A 4 inches of Hg vacuum
  2. B 10 inches of Hg vacuum
  3. C 0 inches of Hg vacuum
  4. D 15 inches of Hg vacuum

57. A comfort-cooling chiller contains 400 pounds of R-134a. Using recovery equipment manufactured in 2021, what evacuation level is required before a major repair?

  1. A 10 inches of Hg vacuum
  2. B 15 inches of Hg vacuum
  3. C 4 inches of Hg vacuum
  4. D 25 mm Hg absolute

58. An R-500 system with a 250-pound charge is being retired. The recovery machine was made in 1992. What evacuation level must be reached?

  1. A 15 inches of Hg vacuum
  2. B 10 inches of Hg vacuum
  3. C 4 inches of Hg vacuum
  4. D 0 inches of Hg vacuum

59. A technician is disposing of a 30-pound R-22 rooftop unit using a recovery machine built in 2018. What is the required evacuation level?

  1. A 0 inches of Hg vacuum
  2. B 10 inches of Hg vacuum
  3. C 4 inches of Hg vacuum
  4. D Recovery of 90 percent of the charge

60. A large R-22 system holds 500 pounds in total. The technician isolates a section holding 150 pounds and will open only that section. Using post-1993 recovery equipment, to what level must the isolated section be evacuated?

  1. A 10 inches of Hg vacuum
  2. B 4 inches of Hg vacuum
  3. C 15 inches of Hg vacuum
  4. D 0 inches of Hg vacuum

61. A technician will replace a filter-drier on a 60-pound R-22 system. The job is not a major repair and the system will not be evacuated to the atmosphere afterward. What is the minimum evacuation required before opening?

  1. A To 10 inches of Hg vacuum
  2. B To 4 inches of Hg vacuum
  3. C To no higher than 0 psig
  4. D To no higher than 5 psig

62. Leaks in an R-22 appliance make it impossible to reach the Table 1 level. What is the highest pressure the leaking component may be at when it is opened?

  1. A 5 psig
  2. B 0 psig
  3. C 10 inches of Hg vacuum
  4. D 15 psig

63. A 220-pound R-22 system has a badly leaking evaporator. The technician can isolate the evaporator from the rest of the system. What must happen to the non-leaking components that will be opened?

  1. A They may be opened at 0 psig like the leaking part
  2. B They need no evacuation if they are isolated
  3. C They must be evacuated to the Table 1 level
  4. D They may be opened once liquid is removed

64. A technician needs to change the compressor oil in a 90-pound R-22 system. To what pressure must the system, or the isolated portion, be brought before the oil is removed?

  1. A No higher than 0 psig
  2. B No higher than 15 psig
  3. C No higher than 10 inches of Hg vacuum
  4. D No higher than 5 psig

65. Under the definition in 40 CFR 82.152, which of these jobs is a major repair?

  1. A Replacing the compressor
  2. B Replacing a Schrader valve core
  3. C Adding refrigerant through the service port
  4. D Tightening a flare nut

66. Apart from removing a listed component, a repair counts as major if it uncovers an opening of more than how much flow area, for how long?

  1. A 2 square inches for more than 30 minutes
  2. B 4 square inches for more than 15 minutes
  3. C 4 square inches for more than 60 minutes
  4. D 8 square inches for more than 15 minutes

67. Which of these repairs on a 70-pound R-410A system is not a major repair, assuming the opening is small and brief?

  1. A Replacing the evaporator coil
  2. B Replacing the condenser coil
  3. C Replacing the expansion valve
  4. D Replacing the compressor

68. What is the largest full charge on which system-dependent recovery equipment may be used, unless it is a permanently attached pump-out unit?

  1. A 5 pounds
  2. B 50 pounds
  3. C 200 pounds
  4. D 15 pounds

69. A 40-pound R-22 system needs refrigerant removed. In which case may system-dependent recovery equipment be used on it?

  1. A When the system's own compressor is still running normally
  2. B When the job is not a major repair
  3. C When the recovery cylinder is chilled
  4. D When it is permanently attached as a pump-out unit

70. After recovering R-22 from a 100-pound system for a compressor change, what must the technician do before opening it?

  1. A Verify the required evacuation level was reached
  2. B Add nitrogen to bring the pressure back above 0 psig
  3. C Have the owner sign a recovery record
  4. D Wait 24 hours for the oil to settle

71. An R-22 system has service valves that let the technician pump the charge into the receiver and isolate it there. What does the rule allow?

  1. A Venting the small amount left in the open section
  2. B Opening the section without any further checks
  3. C Evacuating only the part being serviced
  4. D Skipping evacuation if the job is under 15 minutes

72. Which activity is not considered opening an appliance under 40 CFR 82.152?

  1. A Cutting a refrigerant line to replace a drier
  2. B Removing a leaking service valve
  3. C Unbrazing a condenser coil
  4. D Connecting gauges to measure pressures

73. Which technician certification is required to service a 150-pound R-134a chiller, a medium-pressure appliance?

  1. A Type I
  2. B Type II
  3. C Type III
  4. D No certification is needed

74. Table 1 gives different vacuum levels for equipment made before and after November 15, 1993. Which piece of equipment does that date refer to?

  1. A The appliance being serviced
  2. B The vacuum gauge used to check the level
  3. C The refrigerant cylinder
  4. D The recovery or recycling equipment

Refrigeration

75. A technician arrives at an unfamiliar packaged unit and needs to know which refrigerant it uses. Where should they look first?

  1. A The color of the suction line insulation
  2. B The unit's nameplate
  3. C The size of the service valves
  4. D The thermostat model

76. A suction gauge reads 100 psig. What is that pressure in psia?

  1. A 85.3 psia
  2. B 100 psia
  3. C 114.7 psia
  4. D 129.4 psia

77. A pressure-temperature table lists a saturation pressure of 250 psia. What would a gauge read at that pressure?

  1. A 235.3 psig
  2. B 250 psig
  3. C 264.7 psig
  4. D 279.4 psig

78. A refrigerant has a liquid-phase saturation pressure of 200 psia at 104 °F. How does 40 CFR 82.152 classify an appliance that uses it?

  1. A Low-pressure
  2. B Medium-pressure
  3. C Very high-pressure
  4. D High-pressure

79. Under the 40 CFR 82.152 definitions, an appliance using R-134a is which kind of appliance?

  1. A Low-pressure
  2. B Medium-pressure
  3. C High-pressure
  4. D Very high-pressure

80. A laboratory freezer cascade stage uses R-23. Which pressure class is it?

  1. A Very high-pressure
  2. B High-pressure
  3. C Medium-pressure
  4. D Low-pressure

81. A refrigerant's critical temperature is below 104 °F. How is an appliance using it classified?

  1. A Medium-pressure
  2. B High-pressure
  3. C Very high-pressure
  4. D Low-pressure

82. In an operating R-22 system, what is in the receiver?

  1. A Low-pressure vapor
  2. B High-pressure liquid
  3. C A low-pressure liquid and vapor mix
  4. D High-pressure superheated vapor

83. What is the job of a suction line accumulator in a heat pump using R-410A?

  1. A To store high-pressure liquid for the metering device
  2. B To remove moisture from the liquid line
  3. C To raise the discharge pressure
  4. D To trap liquid so it does not reach the compressor

84. What happens to the refrigerant inside the evaporator of an R-410A system?

  1. A Low-pressure liquid boils into vapor as it absorbs heat
  2. B High-pressure vapor condenses into liquid
  3. C Vapor is compressed to a higher pressure
  4. D Liquid is subcooled before it reaches the metering device

85. In the condenser of an R-22 system, the refrigerant:

  1. A boils from liquid to vapor at low pressure as it absorbs heat
  2. B gives up heat and changes from high-pressure vapor to liquid
  3. C is throttled to a lower pressure
  4. D stays as low-pressure vapor

86. What is in the discharge line between the compressor and condenser of an R-407C system?

  1. A Low-pressure saturated vapor
  2. B High-pressure subcooled liquid
  3. C High-pressure superheated vapor
  4. D Low-pressure liquid and vapor mix

87. What leaves the metering device in an operating R-22 system?

  1. A High-pressure liquid
  2. B High-pressure vapor
  3. C Low-pressure superheated vapor, the same as the suction line
  4. D A low-pressure mix of liquid and vapor

88. In normal operation, what should be in the suction line returning to the compressor of an R-410A system?

  1. A Low-pressure vapor
  2. B High-pressure liquid
  3. C High-pressure vapor
  4. D Low-pressure liquid

89. An owner asks to convert an R-22 split system to propane or another hydrocarbon. What should the technician know?

  1. A Hydrocarbons are approved drop-ins for R-22
  2. B Hydrocarbons are approved for retrofits if the oil is changed
  3. C Hydrocarbons are not approved for retrofitting these systems
  4. D Hydrocarbons are approved for retrofits under 50 pounds

90. An idle R-22 system with both liquid and vapor inside has been sitting in a 75 °F room. What does its pressure tell the technician?

  1. A Nothing, because idle pressure is random
  2. B The saturation pressure of R-22 at about 75 °F
  3. C The amount of refrigerant in the system
  4. D The pressure the compressor produced the last time it ran

Safety

91. An R-410A system has just been evacuated to a deep vacuum after a repair. Why should the hermetic compressor not be started yet?

  1. A Running it under vacuum can damage the motor
  2. B It will cool the system too fast
  3. C It will void the recovery machine's certification
  4. D It will raise the system's superheat

92. What is the main risk of energizing a hermetic compressor while the system is in a deep vacuum?

  1. A The oil will freeze
  2. B The refrigerant will decompose into acids and sludge
  3. C The suction line will collapse
  4. D Breakdown of the motor winding insulation

93. After evacuating an R-22 system, a technician wants to check that the hermetic compressor runs. What should be done first?

  1. A Start it for a few seconds to listen for noise
  2. B Pull the vacuum deeper
  3. C Break the vacuum by charging refrigerant
  4. D Disconnect the crankcase heater

94. According to EPA's Type II test outline, which sensor does ASHRAE Standard 15 require in equipment rooms, whatever the refrigerant?

  1. A A smoke detector
  2. B A carbon monoxide detector near the door
  3. C A humidity sensor
  4. D An oxygen deprivation sensor

95. Why can a large R-134a leak in an enclosed equipment room be dangerous even though R-134a has low toxicity?

  1. A R-134a burns easily in air
  2. B R-134a turns into carbon monoxide
  3. C Its heavy vapor can displace the oxygen in the room
  4. D R-134a reacts with oxygen in the room to form ozone

96. A technician is pressurizing an R-22 system with nitrogen for a leak test. What must be used between the nitrogen cylinder and the system?

  1. A A pressure regulator
  2. B A recovery machine
  3. C A filter-drier
  4. D A sight glass

97. Why must oxygen never be used to pressurize a refrigeration system for leak testing?

  1. A It reacts with the refrigerant to form hydrochloric acid
  2. B It can explode in contact with compressor oil
  3. C It leaks out too fast to measure
  4. D It is not detectable by any test

98. How high may nitrogen pressure go when leak testing the low side of an R-410A system?

  1. A To the full nitrogen cylinder pressure
  2. B To twice the high-side pressure seen in normal operation
  3. C No higher than the test pressure on the nameplate
  4. D To any pressure if a regulator is used

99. A technician is recovering liquid R-22 from a 250-pound system. What protective equipment is most important against liquid refrigerant spray?

  1. A Hearing protection
  2. B A hard hat
  3. C Steel-toe boots and a hard hat
  4. D Safety glasses and gloves

100. Does the equipment room oxygen deprivation requirement in EPA's test outline apply when the chiller uses an HFC rather than a CFC or HCFC?

  1. A Yes, it applies with all refrigerants
  2. B No, it applies only to CFCs
  3. C No, it applies only to flammable refrigerants
  4. D Only if the room has no windows

Answer key

Leak detection

1. An R-410A split system is cooling poorly, and the technician measures excessive superheat at the evaporator outlet. What does this most likely point to?
  • An overcharge of refrigerant
  • A dirty condenser coil
  • A leak that has left it underchargedCorrect answer
  • Too much airflow over the condenser

Why “A leak that has left it undercharged” is correct

EPA lists excessive superheat as a sign of leakage in high-pressure systems. With too little refrigerant, the liquid boils off early in the evaporator and the vapor keeps picking up heat, so superheat climbs.

Source: EPA: Test Topics

Why the other answers are wrong

  • An overcharge of refrigerant — An overcharge tends to lower superheat, not raise it.
  • A dirty condenser coil — A dirty condenser mainly raises head pressure; it is not the classic sign of a leak.
  • Too much airflow over the condenser — Extra condenser airflow does not cause high evaporator superheat.
2. While inspecting a hermetic R-22 system, a technician finds an oily film around a brazed joint on the suction line. Why is this worth checking with a leak detector?
  • Oil residue at a joint is a common sign of a refrigerant leakCorrect answer
  • It shows the compressor has too much oil
  • It means the joint was overheated when it was brazed at the factory
  • It shows moisture has entered the system

Why “Oil residue at a joint is a common sign of a refrigerant leak” is correct

Refrigerant carries compressor oil around the circuit, so oil escapes with refrigerant at a leak and leaves a trace. EPA names traces of oil as a sign of leakage in hermetic systems.

Source: EPA: Test Topics

Why the other answers are wrong

  • It shows the compressor has too much oil — Oil outside a joint does not measure the compressor's oil level.
  • It means the joint was overheated when it was brazed at the factory — Overheating while brazing does not by itself leave an oily film.
  • It shows moisture has entered the system — Moisture inside the system does not show up as oil on the outside of a joint.
3. A technician has just replaced a leaking evaporator coil on an R-22 system. What should be done before the system is recharged?
  • Run the compressor briefly to check rotation
  • Leak test the systemCorrect answer
  • Add a small amount of oil
  • Charge it by sight glass

Why “Leak test the system” is correct

EPA stresses the need to leak test before charging or recharging equipment. Finding a leak while the system holds only test gas avoids losing a new charge of refrigerant.

Source: EPA: Test Topics; 40 CFR 82.157(e)(1)

Why the other answers are wrong

  • Run the compressor briefly to check rotation — Running a hermetic compressor on an evacuated system can damage it, and it is not a leak check.
  • Add a small amount of oil — Adding oil is not a substitute for proving the system is tight.
  • Charge it by sight glass — Charging before leak testing risks losing the new charge through an unfound leak.
4. Which gas does EPA's test outline list as the best choice for pressurizing a high-pressure system for a leak test?
  • Pure R-22
  • Compressed air
  • Oxygen
  • Nitrogen aloneCorrect answer

Why “Nitrogen alone” is correct

Nitrogen alone is listed as the preferred leak test gas. It is inert, dry, inexpensive, and exempt from the venting prohibition, so releasing it after the test harms nothing.

Source: EPA: Test Topics; 40 CFR 82.154(a)

Why the other answers are wrong

  • Pure R-22 — Pure refrigerant is the least preferred choice because it is lost when the test gas is released.
  • Compressed air — Compressed air brings in moisture and can form an explosive mix with oil under pressure.
  • Oxygen — Oxygen can explode in contact with compressor oil and must never be used.
5. Rank these leak test gases from most to least preferred, following EPA's test outline.
  • Pure refrigerant, nitrogen with trace R-22, nitrogen alone
  • Nitrogen with trace R-22, nitrogen alone, pure refrigerant
  • Nitrogen alone, nitrogen with trace R-22, pure refrigerantCorrect answer
  • Nitrogen alone, pure refrigerant, nitrogen with trace R-22

Why “Nitrogen alone, nitrogen with trace R-22, pure refrigerant” is correct

EPA's order is nitrogen alone first, then nitrogen with a trace quantity of R-22, then pure refrigerant last. Each step down releases more refrigerant when the test gas is let out.

Source: EPA: Test Topics

Why the other answers are wrong

  • Pure refrigerant, nitrogen with trace R-22, nitrogen alone — This is the order reversed; pure refrigerant is the least preferred.
  • Nitrogen with trace R-22, nitrogen alone, pure refrigerant — Nitrogen alone ranks above nitrogen with a trace gas.
  • Nitrogen alone, pure refrigerant, nitrogen with trace R-22 — Pure refrigerant ranks below nitrogen with a trace of R-22.
6. Why might a technician add a trace amount of R-22 to the nitrogen used to pressure test a system?
  • So an electronic leak detector can sense the escaping gasCorrect answer
  • To lubricate the compressor during the test
  • To raise the test pressure without using any more nitrogen
  • To dry out moisture inside the system

Why “So an electronic leak detector can sense the escaping gas” is correct

Electronic leak detectors respond to halogenated refrigerants, not to nitrogen. A small trace of R-22 in the nitrogen lets the detector find where the test gas escapes while keeping refrigerant use low.

Source: EPA: Test Topics

Why the other answers are wrong

  • To lubricate the compressor during the test — A trace of refrigerant does not lubricate the compressor.
  • To raise the test pressure without using any more nitrogen — The amount is too small to matter for pressure; nitrogen supplies the pressure.
  • To dry out moisture inside the system — R-22 does not dry the system; evacuation removes moisture.
7. Why is pressurizing a system with pure refrigerant the least preferred way to leak test it?
  • Refrigerant cannot reach a high enough pressure
  • Refrigerant reacts with brazed joints
  • Electronic detectors cannot sense a pure refrigerant charge
  • Refrigerant is released when the test gas is let outCorrect answer

Why “Refrigerant is released when the test gas is let out” is correct

Whatever gas is used to pressurize the system is eventually released or lost through the leak. Using pure refrigerant means a full test charge of refrigerant escapes, which is why EPA ranks it below nitrogen and nitrogen with a trace gas.

Source: EPA: Test Topics

Why the other answers are wrong

  • Refrigerant cannot reach a high enough pressure — Pressure is not the problem; emissions are.
  • Refrigerant reacts with brazed joints — Refrigerant does not attack brazed joints during a leak test.
  • Electronic detectors cannot sense a pure refrigerant charge — Electronic detectors sense pure refrigerant well; that is not the drawback.
8. A sight glass check and a standing pressure test both show that a 200-pound R-22 system is leaking. Under the Part 82 definition of leak inspection, what else is required?
  • Nothing; either check alone is a complete leak inspection
  • A method that finds the leak's locationCorrect answer
  • A refrigerant analysis by a reclaimer
  • A second standing pressure test a week later

Why “A method that finds the leak's location” is correct

Methods that show a system is leaking but not where, such as standing pressure or vacuum decay tests, sight glass checks, receiver levels and charging charts, must be used together with a method that can find the leak's location.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Nothing; either check alone is a complete leak inspection — Those checks show a leak exists but do not locate it, so they are not enough on their own.
  • A refrigerant analysis by a reclaimer — Refrigerant analysis says nothing about where the leak is.
  • A second standing pressure test a week later — Repeating a decay test still does not locate the leak.
9. Who must perform the leak inspection required on a 150-pound R-22 comfort-cooling chiller that has exceeded its trigger rate?
  • The building owner
  • Any maintenance employee
  • A certified technicianCorrect answer
  • An EPA inspector

Why “A certified technician” is correct

Under 82.157(g)(2), leak inspections must be conducted by a certified technician using methods the technician judges appropriate for the appliance. The technician must give the owner documentation of the inspection.

Source: 40 CFR 82.157(g)(2); 40 CFR 82.157(l)(3)

Why the other answers are wrong

  • The building owner — The owner is responsible for having it done but cannot do it without certification.
  • Any maintenance employee — The rule requires a certified technician, not just any employee.
  • An EPA inspector — EPA does not perform routine leak inspections for owners.
10. A cold storage warehouse system holds 600 pounds of R-22 and has exceeded the 20 percent leak rate. How often must it receive leak inspections?
  • Once a year until it stays under the rate for one year
  • Once a month until the leak is repaired
  • Only once, after the repair
  • Every three months until four clean quarters in a rowCorrect answer

Why “Every three months until four clean quarters in a row” is correct

Commercial and industrial process refrigeration appliances of 500 pounds or more that exceed the trigger rate must be inspected every three months until the leak rate stays under the trigger for four consecutive quarters. Smaller ones, and comfort cooling, are inspected yearly.

Source: 40 CFR 82.157(g)(1)

Why the other answers are wrong

  • Once a year until it stays under the rate for one year — Annual inspections apply to systems under 500 pounds and to comfort cooling.
  • Once a month until the leak is repaired — No monthly inspection schedule exists in the rule.
  • Only once, after the repair — Inspections continue on a schedule, not just once.
11. During a required leak inspection of a 300-pound R-22 commercial system, which components may the technician skip?
  • Components more than two meters above a support surfaceCorrect answer
  • Any component behind an access panel
  • Components on the high side
  • Components installed more than ten years before the inspection

Why “Components more than two meters above a support surface” is correct

All visible and accessible components must be inspected, except those that are insulated, under ice, underground or behind walls, those that require personnel to be elevated more than two meters, and those site personnel judge unsafe.

Source: 40 CFR 82.157(g)(3)

Why the other answers are wrong

  • Any component behind an access panel — Components behind a removable access panel are still accessible.
  • Components on the high side — The high side is not exempt from inspection.
  • Components installed more than ten years before the inspection — Age of the components is not an exception.
12. An automatic leak detection system that senses refrigerant in the air replaces quarterly inspections on a 900-pound R-22 system indoors. What must it be able to do?
  • Detect 100 ppm and alarm at 1,000 ppm
  • Detect 10 ppm and alert the owner at 100 ppmCorrect answer
  • Detect 50 ppm and automatically shut down the compressor
  • Detect 1 ppm and notify EPA directly

Why “Detect 10 ppm and alert the owner at 100 ppm” is correct

An air-sampling automatic leak detection system must accurately detect 10 parts per million of the refrigerant and alert the owner or operator at 100 parts per million. It must also be audited or calibrated every year.

Source: 40 CFR 82.157(g)(4)

Why the other answers are wrong

  • Detect 100 ppm and alarm at 1,000 ppm — These numbers are ten times too high.
  • Detect 50 ppm and automatically shut down the compressor — The rule does not set 50 ppm or require a compressor shutdown.
  • Detect 1 ppm and notify EPA directly — The system alerts the owner or operator, not EPA.

Leak repair requirements

13. A supermarket display case system holds 80 pounds of R-22. Under 40 CFR Part 82, above what annual leak rate must the owner repair it?
  • 10 percent
  • 20 percentCorrect answer
  • 30 percent
  • 35 percent

Why “20 percent” is correct

Commercial refrigeration, meaning retail food and cold storage equipment, has a 20 percent trigger leak rate under Part 82. The rule applies here because the appliance holds 50 pounds or more of an HCFC.

Source: 40 CFR 82.157(c); EPA: Leak Repair Requirements

Why the other answers are wrong

  • 10 percent — 10 percent is the rate for comfort cooling and other appliances.
  • 30 percent — 30 percent is the rate for industrial process refrigeration.
  • 35 percent — 35 percent was the old commercial and industrial rate that applied before 2019.
14. A chemical plant's process cooling system holds 600 pounds of R-22. What trigger leak rate applies to it under 40 CFR Part 82?
  • 10 percent
  • 20 percent
  • 35 percent
  • 30 percentCorrect answer

Why “30 percent” is correct

Industrial process refrigeration, the complex custom systems tied directly to chemical, pharmaceutical, petrochemical and manufacturing processes, has a 30 percent trigger rate under 82.157(c).

Source: 40 CFR 82.157(c); 40 CFR 82.152

Why the other answers are wrong

  • 10 percent — 10 percent is for comfort cooling and other appliances.
  • 20 percent — 20 percent is for commercial refrigeration such as supermarkets.
  • 35 percent — 35 percent was the old pre-2019 threshold.
15. An office building's comfort-cooling chiller holds 150 pounds of R-22. Under 40 CFR Part 82, above what annual leak rate must leaks be repaired?
  • 10 percentCorrect answer
  • 15 percent
  • 20 percent
  • 30 percent

Why “10 percent” is correct

Comfort cooling appliances, and any other appliance with 50 or more pounds that is not commercial or industrial process refrigeration, have a 10 percent trigger rate. Chillers used to cool occupied buildings are named as comfort cooling in the definition.

Source: 40 CFR 82.157(c); 40 CFR 82.152

Why the other answers are wrong

  • 15 percent — No category has a 15 percent rate.
  • 20 percent — 20 percent is the commercial refrigeration rate.
  • 30 percent — 30 percent is the industrial process refrigeration rate.
16. A rooftop unit holds 100 pounds of R-410A, an HFC. Does the Part 82 leak repair section, 40 CFR 82.157, apply to it?
  • Yes, because it holds more than 50 pounds
  • Yes, at the 20 percent commercial rate
  • No, it covers only ozone-depleting refrigerantsCorrect answer
  • No, because rooftop units are exempt from all leak rules

Why “No, it covers only ozone-depleting refrigerants” is correct

Since April 10, 2020, 82.157 applies only to appliances with 50 or more pounds of a class I or class II refrigerant, and not to appliances containing only substitutes such as HFCs. An HFC appliance like this may instead fall under the separate 40 CFR Part 84 leak repair rule, which started January 1, 2026.

Source: 40 CFR 82.157(a); 40 CFR 84.106(a)

Why the other answers are wrong

  • Yes, because it holds more than 50 pounds — The 50-pound threshold counts only class I or class II refrigerant under Part 82.
  • Yes, at the 20 percent commercial rate — A rooftop unit is comfort cooling, and Part 82 leak repair does not cover HFCs anyway.
  • No, because rooftop units are exempt from all leak rules — Rooftop units have no blanket exemption; an R-22 rooftop unit of 50 pounds or more is covered by 82.157.
17. A commercial split system holds 40 pounds of R-22 and is leaking 25 percent a year. Is the owner subject to the Part 82 leak repair requirements?
  • Yes, the comfort cooling rate is 10 percent
  • No, the appliance holds less than 50 poundsCorrect answer
  • Yes, any HCFC leak must be repaired within 30 days
  • No, because R-22 is no longer produced

Why “No, the appliance holds less than 50 pounds” is correct

The leak repair requirements in 82.157 apply only to appliances with a full charge of 50 or more pounds of class I or class II refrigerant. At 40 pounds this system is below the threshold, though venting is still prohibited.

Source: 40 CFR 82.157(a); EPA: Leak Repair Requirements

Why the other answers are wrong

  • Yes, the comfort cooling rate is 10 percent — The 10 percent rate only matters once the appliance holds 50 pounds or more.
  • Yes, any HCFC leak must be repaired within 30 days — There is no 30-day rule for appliances below 50 pounds.
  • No, because R-22 is no longer produced — Production status does not decide whether the leak rules apply.
18. A 200-pound R-22 comfort-cooling chiller is found leaking above its trigger rate. Unless an exception applies, how long does the owner have to repair the leaks?
  • 10 days
  • 30 daysCorrect answer
  • 120 days
  • One year

Why “30 days” is correct

Leaks must be identified and repaired within 30 days of when refrigerant is added to an appliance that exceeds the trigger rate. The 120-day period applies only when an industrial process shutdown is needed.

Source: 40 CFR 82.157(d); EPA: Leak Repair Requirements

Why the other answers are wrong

  • 10 days — 10 days is the window for the follow-up verification test.
  • 120 days — 120 days applies only when an industrial process shutdown is required.
  • One year — One year is the deadline for completing a retrofit or retirement plan.
19. Repairing a leak on a 700-pound R-22 industrial process system requires shutting down the process it serves. How long does the owner have to complete the repair?
  • 30 days
  • 180 days
  • 120 daysCorrect answer
  • 270 days

Why “120 days” is correct

Where an industrial process shutdown is required, a 120-day repair period replaces the normal 30 days. Extensions beyond that are possible only under specific conditions such as unavailable parts.

Source: 40 CFR 82.157(d); EPA: Leak Repair Requirements

Why the other answers are wrong

  • 30 days — 30 days is the normal repair period when no process shutdown is needed.
  • 180 days — 180 days is the outer limit of the parts extension when no shutdown is needed.
  • 270 days — 270 days is the outer limit of the parts extension when a shutdown is needed.
20. A leak on a 300-pound R-22 chiller was repaired after the system was evacuated. When must the initial verification test be done?
  • Within 10 days after the chiller returns to normal operation
  • Before any refrigerant is added back to the chillerCorrect answer
  • Only after the full charge has been restored
  • At the next annual leak inspection

Why “Before any refrigerant is added back to the chiller” is correct

For repairs that required evacuating the appliance or a portion of it, the initial verification test must be done before adding any refrigerant. It confirms the repaired leaks hold before refrigerant is put at risk.

Source: 40 CFR 82.157(e)(1); 40 CFR 82.152

Why the other answers are wrong

  • Within 10 days after the chiller returns to normal operation — That describes the timing of the follow-up verification test.
  • Only after the full charge has been restored — Testing after recharging defeats the purpose of the initial test.
  • At the next annual leak inspection — The annual inspection is a separate requirement and is far too late.
21. A leak on a 90-pound R-22 commercial refrigeration system passed its initial verification test without the system being evacuated. When must the follow-up verification test be performed?
  • Within 30 days of the successful initial test
  • Within 10 days of the successful initial testCorrect answer
  • Before the next refrigerant addition
  • Within 12 months of the repair

Why “Within 10 days of the successful initial test” is correct

A follow-up verification test must be performed within 10 days of the successful initial verification test, or within 10 days of the appliance reaching normal operating conditions if it was evacuated for the repair.

Source: 40 CFR 82.157(e)(2); EPA: Leak Repair Requirements

Why the other answers are wrong

  • Within 30 days of the successful initial test — 30 days is the repair period, not the follow-up window.
  • Before the next refrigerant addition — The follow-up test is tied to the initial test, not to the next addition.
  • Within 12 months of the repair — 12 months relates to presuming repairs successful, not to the follow-up test.
22. A replacement compressor for a leaking 400-pound R-22 commercial system cannot be delivered within 30 days. If the extension rules are met, how much extra time is allowed?
  • Up to 30 days after delivery, but no more than 180 days in totalCorrect answer
  • Up to 90 days after the parts arrive, with no overall time limit at all
  • An automatic extra year from the leak date
  • Up to 120 days, regardless of delivery date

Why “Up to 30 days after delivery, but no more than 180 days in total” is correct

When needed components are not available within 30 days, additional time is allowed up to 30 days after receiving them, not to exceed 180 days from the date the leak rate was exceeded. The limit is 270 days if an industrial process shutdown is required.

Source: 40 CFR 82.157(f)(1)(iii)

Why the other answers are wrong

  • Up to 90 days after the parts arrive, with no overall time limit at all — The window is 30 days after delivery and is capped at 180 days.
  • An automatic extra year from the leak date — No automatic one-year extension exists for repairs.
  • Up to 120 days, regardless of delivery date — 120 days is the industrial process shutdown period, not the parts extension.
23. The owner of a 250-pound R-22 chiller needs more than 30 days to finish repairs because parts are back-ordered. By when must the extension request reach EPA?
  • Within 30 days of the appliance exceeding the leak rateCorrect answer
  • Within 6 months of the leak
  • Before the next scheduled annual leak inspection of the system
  • By March 1 of the following year

Why “Within 30 days of the appliance exceeding the leak rate” is correct

An extension request must be sent to EPA within 30 days, or 120 days if a process shutdown is required, of the appliance exceeding the trigger rate. The owner must also document all repair efforts and the reason more time is needed.

Source: 40 CFR 82.157(f)(4)

Why the other answers are wrong

  • Within 6 months of the leak — Six months is far beyond the window the rule allows.
  • Before the next scheduled annual leak inspection of the system — Inspection schedules do not set the extension deadline.
  • By March 1 of the following year — March 1 is the deadline for chronic leaker reports.
24. The owner of a leaking 180-pound R-22 chiller decides to retire it rather than repair it. How soon must a retirement plan be created?
  • Within 10 days of the first refrigerant addition after the leak
  • Within 30 days of the appliance exceeding the leak rateCorrect answer
  • Within 6 months of the leak
  • Within one year of the leak

Why “Within 30 days of the appliance exceeding the leak rate” is correct

A retrofit or retirement plan must be created within 30 days of the appliance leaking above its trigger rate when the owner chooses to retrofit or retire instead of repair. The work under the plan then has to be finished within one year of the plan's date.

Source: 40 CFR 82.157(h)(1); EPA: Leak Repair Requirements

Why the other answers are wrong

  • Within 10 days of the first refrigerant addition after the leak — 10 days is the follow-up verification window.
  • Within 6 months of the leak — Six months is not a plan deadline under 82.157.
  • Within one year of the leak — One year is the time to complete the plan, not to write it.
25. Unless granted extra time, how long does an owner have to complete the work in a retrofit or retirement plan for a leaking R-22 appliance of 50 pounds or more?
  • 30 days from the plan's date
  • Six months from the plan's date
  • One year from the plan's dateCorrect answer
  • Two years from the plan's date

Why “One year from the plan's date” is correct

All work under the plan must be finished within one year of the plan's date, and no later than 13 months from when the plan was required. Extensions are available only in limited cases.

Source: 40 CFR 82.157(h)(5); EPA: Leak Repair Requirements

Why the other answers are wrong

  • 30 days from the plan's date — 30 days is the time to create the plan, not to carry it out.
  • Six months from the plan's date — Six months is too short; the rule allows one year.
  • Two years from the plan's date — Two years exceeds the standard schedule.
26. Which requirement applies to a retrofit or retirement plan for a leaking 300-pound R-22 commercial refrigeration system?
  • It must be signed by the technician who first found the leak
  • It must be mailed to EPA within 10 days
  • It must be filed with the state fire marshal
  • It must be signed by a company official and kept on siteCorrect answer

Why “It must be signed by a company official and kept on site” is correct

The plan must be signed by an authorized company official, dated, kept at the appliance site in paper or electronic form, and available to EPA on request. It is not routinely sent to EPA.

Source: 40 CFR 82.157(h)(3); EPA: Leak Repair Requirements

Why the other answers are wrong

  • It must be signed by the technician who first found the leak — The rule calls for an authorized company official, not the technician.
  • It must be mailed to EPA within 10 days — The plan is kept on site and shown to EPA on request, not mailed within 10 days.
  • It must be filed with the state fire marshal — No filing with a fire marshal is required by this rule.
27. After writing a retirement plan for a leaking 120-pound R-22 chiller, the owner finds the leak rate is now below 10 percent. Within what time of the plan's date must this be established to ask EPA for relief from retiring it?
  • 30 days
  • 90 days
  • 1 year
  • 180 daysCorrect answer

Why “180 days” is correct

The owner may ask EPA for relief from the retrofit or retirement obligation by establishing, within 180 days of the plan's date, that the appliance no longer exceeds the leak rate. The owner must also agree in writing to repair all identified leaks within one year of the plan's date.

Source: 40 CFR 82.157(h)(5)(ii); EPA: Leak Repair Requirements

Why the other answers are wrong

  • 30 days — 30 days is the time to write the plan, not to seek relief.
  • 90 days — 90 days is not a deadline in this rule.
  • 1 year — One year is the time to complete the plan.
28. A 200-pound R-22 appliance leaked 260 pounds of refrigerant during one calendar year. What must the owner do?
  • Submit a report to EPA by March 1 of the following yearCorrect answer
  • Retire the appliance within 30 days
  • Notify the state within 10 days
  • Nothing more, as long as each individual leak was repaired

Why “Submit a report to EPA by March 1 of the following year” is correct

An appliance of 50 pounds or more that leaks 125 percent or more of its full charge in a calendar year is a chronic leaker. The owner must report to EPA by March 1 of the next year, describing efforts to find and repair the leaks. Here 260 pounds is 130 percent of the charge.

Source: 40 CFR 82.157(j)

Why the other answers are wrong

  • Retire the appliance within 30 days — Chronic leaking triggers a report, not automatic retirement within 30 days.
  • Notify the state within 10 days — The report goes to EPA, not the state, and is due March 1.
  • Nothing more, as long as each individual leak was repaired — The report is required even if individual leaks were repaired.
29. How long must records required under the Part 82 leak repair rules be kept, unless the rule says otherwise?
  • One year
  • Three yearsCorrect answer
  • Five years
  • For the life of the appliance

Why “Three years” is correct

All records under 82.157(l) must be kept for at least three years in paper or electronic form. Full charge records are kept until three years after the appliance is retired.

Source: 40 CFR 82.157(l)

Why the other answers are wrong

  • One year — One year is too short.
  • Five years — Five years is longer than the rule requires.
  • For the life of the appliance — Only the full charge records run past retirement, and then only by three years.
30. A contractor adds 12 pounds of R-22 to a customer's 150-pound chiller. What does 40 CFR 82.157 require the contractor to give the owner?
  • A copy of the technician's Section 608 certification wallet card
  • A new nameplate showing the charge
  • A signed retrofit plan
  • A record including the amount and type of refrigerant addedCorrect answer

Why “A record including the amount and type of refrigerant added” is correct

Anyone adding or removing refrigerant must give the owner documentation at the end of the service. It includes the appliance identity, date, parts serviced, type of service, technician name, and the amount and type of refrigerant added.

Source: 40 CFR 82.157(b); 40 CFR 82.157(l)(2)

Why the other answers are wrong

  • A copy of the technician's Section 608 certification wallet card — The certification card is not part of the required service record.
  • A new nameplate showing the charge — Nothing in the rule requires a new nameplate.
  • A signed retrofit plan — A retrofit plan is the owner's document and only applies in certain cases.
31. The owner of a 300-pound R-22 chiller must calculate the leak rate every time refrigerant is added, except when the addition:
  • is less than 5 pounds
  • is made by the owner's own technician
  • is made in the first month of the calendar year
  • follows a retrofit or is a seasonal varianceCorrect answer

Why “follows a retrofit or is a seasonal variance” is correct

The leak rate must be calculated after every addition unless it is made immediately after a retrofit, at installation of a new appliance, or qualifies as a seasonal variance. No size or staffing exception exists.

Source: 40 CFR 82.157(b); 40 CFR 82.152

Why the other answers are wrong

  • is less than 5 pounds — No minimum amount exempts an addition from the calculation.
  • is made by the owner's own technician — Who does the work does not matter.
  • is made in the first month of the calendar year — The calendar month has nothing to do with it.
32. A 100-pound R-22 comfort-cooling system needed 10 pounds to return to full charge, and the last addition was 73 days ago. Using the annualizing method, what is the leak rate?
  • 10 percent
  • 20 percent
  • 50 percentCorrect answer
  • 73 percent

Why “50 percent” is correct

Divide pounds added by full charge (10 / 100 = 0.1), divide the days since the last addition by 365 (73 / 365 = 0.2), then divide the first number by the second (0.1 / 0.2 = 0.5) and multiply by 100. The result, 50 percent, is far above the 10 percent comfort cooling rate.

Source: 40 CFR 82.152

Why the other answers are wrong

  • 10 percent — 10 percent is only the share of the charge added, not annualized.
  • 20 percent — 20 percent is the time fraction, not the leak rate.
  • 73 percent — 73 is the number of days, not a percentage.
33. An owner mothballs a leaking 250-pound R-22 commercial refrigeration system by evacuating it and shutting it down. What happens to the repair deadlines?
  • They are suspended until refrigerant is added againCorrect answer
  • They are cancelled permanently
  • They keep running as normal
  • They are extended by exactly one year from the leak date

Why “They are suspended until refrigerant is added again” is correct

Mothballing means evacuating to at least atmospheric pressure and temporarily shutting the appliance down. The repair time frames are suspended while it is mothballed and resume on the day refrigerant is added again.

Source: 40 CFR 82.157(d)(3); 40 CFR 82.152; EPA: Leak Repair Requirements

Why the other answers are wrong

  • They are cancelled permanently — The clock is paused, not cancelled; it resumes when refrigerant goes back in.
  • They keep running as normal — The deadlines are suspended, not running, during mothballing.
  • They are extended by exactly one year from the leak date — No fixed one-year extension comes with mothballing.
34. An office building's comfort-cooling chiller holds 300 pounds of R-134a, an HFC. Under the 40 CFR Part 84 leak repair rule that took effect January 1, 2026, what trigger leak rate applies?
  • 10 percentCorrect answer
  • 20 percent
  • 30 percent
  • No rate; HFC systems are not covered

Why “10 percent” is correct

From January 1, 2026, Part 84 leak repair applies to appliances of 15 pounds or more using an HFC with a global warming potential above 53, such as R-134a, outside the excluded residential and light commercial air conditioning and heat pump subsector. Its rates mirror Part 82: 10 percent for comfort cooling, 20 percent commercial, 30 percent industrial process.

Source: 40 CFR 84.106(a); 40 CFR 84.106(c); 40 CFR 84.102

Why the other answers are wrong

  • 20 percent — 20 percent is the commercial refrigeration rate.
  • 30 percent — 30 percent is the industrial process refrigeration rate.
  • No rate; HFC systems are not covered — A 300-pound R-134a comfort-cooling chiller is covered by Part 84 from January 1, 2026.

Recovery techniques

35. When recovering R-22 from a 200-pound system, why is it best to remove liquid refrigerant first?
  • Liquid recovery moves refrigerant much faster than vaporCorrect answer
  • Liquid cannot be recovered after vapor
  • It keeps the oil in the system
  • It removes the need to reach the required recovery vacuum

Why “Liquid recovery moves refrigerant much faster than vapor” is correct

EPA notes that recovering liquid at the start speeds up the process. A given volume of liquid holds far more refrigerant than the same volume of vapor, so most of the charge moves quickly before the slower vapor phase.

Source: EPA: Test Topics; 40 CFR 82.156(a)

Why the other answers are wrong

  • Liquid cannot be recovered after vapor — Liquid can still be recovered later; it is just slower to leave it.
  • It keeps the oil in the system — Recovering liquid first is about speed, not keeping oil in place.
  • It removes the need to reach the required recovery vacuum — The appliance must still reach the Table 1 level after the liquid is out.
36. A technician wants to recover liquid first from a 150-pound R-22 system with a receiver. Where is the liquid refrigerant normally found when the system is off?
  • In the suction line and accumulator only
  • In the receiver and liquid lineCorrect answer
  • In the discharge line
  • In the compressor crankcase only

Why “In the receiver and liquid line” is correct

The receiver stores high-pressure liquid that leaves the condenser, and the liquid line carries it to the metering device. Connecting there lets the technician draw off liquid first.

Source: EPA: Test Topics

Why the other answers are wrong

  • In the suction line and accumulator only — The suction side mainly holds vapor; any liquid there is not the bulk of the charge.
  • In the discharge line — The discharge line carries hot vapor from the compressor.
  • In the compressor crankcase only — Some refrigerant dissolves in crankcase oil, but the bulk of the liquid is in the receiver.
37. How does chilling the recovery cylinder speed up recovery from an R-410A system?
  • It thickens the oil so less is carried over
  • It lowers cylinder pressure, widening the pressure differenceCorrect answer
  • It lets the cylinder be filled past 80 percent of its liquid capacity
  • It removes non-condensables from the refrigerant

Why “It lowers cylinder pressure, widening the pressure difference” is correct

Cooling the recovery vessel lowers the pressure of the refrigerant inside it. A bigger pressure difference between the appliance and the cylinder makes refrigerant flow into the cylinder faster.

Source: EPA: Test Topics

Why the other answers are wrong

  • It thickens the oil so less is carried over — Oil thickness is not the reason chilling helps.
  • It lets the cylinder be filled past 80 percent of its liquid capacity — Chilling never raises the safe fill limit of a cylinder.
  • It removes non-condensables from the refrigerant — Temperature alone does not separate non-condensables.
38. Why can warming the appliance help when recovering R-22 from a cold rooftop unit in winter?
  • It raises the refrigerant pressure in the applianceCorrect answer
  • It lowers the boiling point of the oil
  • It makes the refrigerant easier to separate from air
  • It lets system-dependent equipment be used

Why “It raises the refrigerant pressure in the appliance” is correct

Heating the appliance, or the vessel refrigerant is being removed from, raises its refrigerant pressure. A higher source pressure pushes refrigerant toward the recovery cylinder faster.

Source: EPA: Test Topics

Why the other answers are wrong

  • It lowers the boiling point of the oil — Heating does not lower the oil's boiling point.
  • It makes the refrigerant easier to separate from air — Warming does not separate air from refrigerant.
  • It lets system-dependent equipment be used — The 15-pound limit on system-dependent equipment applies regardless of temperature.
39. Which step speeds recovery from a 100-pound R-407C system?
  • Heating the recovery cylinder
  • Using the longest, smallest hoses available
  • Chilling the recovery cylinderCorrect answer
  • Recovering vapor before liquid

Why “Chilling the recovery cylinder” is correct

EPA lists chilling the recovery vessel and heating the appliance as ways to speed recovery. Both increase the pressure difference that drives refrigerant into the cylinder.

Source: EPA: Test Topics

Why the other answers are wrong

  • Heating the recovery cylinder — Heating the cylinder raises its pressure and slows recovery.
  • Using the longest, smallest hoses available — Long, narrow hoses restrict flow and slow recovery.
  • Recovering vapor before liquid — Liquid first is faster; vapor first is the slow way round.
40. A technician has finished recovering R-22 and next needs to recover R-410A with the same machine. What should be done first to prevent cross-contamination?
  • Run the machine on R-410A for a minute, then vent the hoses to air
  • Use the same recovery cylinder for both refrigerants
  • Add a small amount of POE oil to the machine
  • Clear the R-22 from the machine and hoses as the manual directsCorrect answer

Why “Clear the R-22 from the machine and hoses as the manual directs” is correct

Refrigerant left in the machine, hoses and filter would mix with the next refrigerant. Clearing it out according to the manufacturer's procedure keeps the next batch clean and avoids releasing refrigerant, as 82.156(g) requires equipment to be used per the manufacturer's directions.

Source: EPA: Test Topics; 40 CFR 82.156(g)

Why the other answers are wrong

  • Run the machine on R-410A for a minute, then vent the hoses to air — Venting hoses releases refrigerant and is prohibited.
  • Use the same recovery cylinder for both refrigerants — Sharing a cylinder mixes the two refrigerants.
  • Add a small amount of POE oil to the machine — Adding oil does nothing to remove leftover R-22.
41. Which practice keeps recovered refrigerants from being mixed?
  • Topping up a cylinder with whatever refrigerant is on hand
  • Labelling the cylinder after it is full
  • Combining partly full cylinders to save space
  • Using a separate recovery cylinder for each refrigerantCorrect answer

Why “Using a separate recovery cylinder for each refrigerant” is correct

Each refrigerant should go into its own recovery cylinder. Mixed refrigerants are hard or impossible to reclaim and may have to be destroyed.

Source: EPA: Test Topics

Why the other answers are wrong

  • Topping up a cylinder with whatever refrigerant is on hand — Adding a different refrigerant contaminates the whole cylinder.
  • Labelling the cylinder after it is full — Labelling late does not prevent mixing; the contents must stay separate from the start.
  • Combining partly full cylinders to save space — Combining cylinders mixes refrigerants if they differ.
42. A shop accidentally recovers R-22 into a cylinder already partly filled with R-410A. What is the usual consequence?
  • The mixture can be reused as R-410A
  • The mixture becomes R-407C
  • The mixture may not be reclaimable and may need destructionCorrect answer
  • The R-22 simply settles out at the bottom and can be drawn off

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

A mixture of two refrigerants generally cannot be separated back into specification refrigerant. It often has to be sent for destruction, which wastes refrigerant and costs money.

Source: EPA: Test Topics; 40 CFR 82.152

Why the other answers are wrong

  • The mixture can be reused as R-410A — A mixture does not meet the specification for either refrigerant.
  • The mixture becomes R-407C — Mixing does not create a different listed blend.
  • The R-22 simply settles out at the bottom and can be drawn off — The two refrigerants do not separate by settling.
43. Why should a technician wait a few minutes after reaching the required vacuum on an R-22 system before opening it?
  • To let the recovery machine cool down
  • To let the compressor oil drain back
  • To see if the pressure rises, showing refrigerant remainsCorrect answer
  • To let any moisture boil out of the refrigerant before opening

Why “To see if the pressure rises, showing refrigerant remains” is correct

EPA's outline calls for waiting after reaching the recovery vacuum to see if system pressure rises. A rise means liquid refrigerant is still in the system or refrigerant is coming out of the oil.

Source: EPA: Test Topics; 40 CFR 82.156(a)

Why the other answers are wrong

  • To let the recovery machine cool down — Cooling the machine is not the purpose of the wait.
  • To let the compressor oil drain back — Oil drain-back is not what the check is for.
  • To let any moisture boil out of the refrigerant before opening — The check looks for refrigerant, not moisture.
44. After shutting off the recovery machine at the required vacuum, the gauge on an R-407C system climbs back toward 0 psig. What should the technician do?
  • Open the system right away
  • Vent the remaining vapor
  • Add nitrogen to push the vapor out, then open it
  • Resume recovery until the level holdsCorrect answer

Why “Resume recovery until the level holds” is correct

A rising pressure shows refrigerant remains in the system or in the oil. Recovery must continue until the required level holds, because the technician must verify that level before opening.

Source: EPA: Test Topics; 40 CFR 82.156(a)

Why the other answers are wrong

  • Open the system right away — The required level has not truly been reached, so opening now would release refrigerant.
  • Vent the remaining vapor — Venting the remaining refrigerant is prohibited.
  • Add nitrogen to push the vapor out, then open it — Adding nitrogen does not remove the refrigerant still in the system.
45. What usually causes the pressure to rise in an R-22 system that has just been pulled down to its recovery vacuum?
  • Refrigerant boiling out of the oil or remaining liquidCorrect answer
  • Air leaking into the system through the gauge set hoses
  • Heat from the recovery machine
  • A failed pressure gauge

Why “Refrigerant boiling out of the oil or remaining liquid” is correct

Liquid refrigerant trapped in low spots, or refrigerant dissolved in the compressor oil, keeps boiling off after the machine stops. That vapor raises the pressure and must be recovered.

Source: EPA: Test Topics

Why the other answers are wrong

  • Air leaking into the system through the gauge set hoses — A small air leak would not usually cause a quick, steady rise, and it is not what the check looks for.
  • Heat from the recovery machine — The recovery machine does not heat the system's refrigerant.
  • A failed pressure gauge — A bad gauge is possible but is not the usual explanation.
46. In the push-pull method of liquid recovery from a large R-22 system, what does the recovery machine do?
  • It pumps liquid directly through its compressor
  • It moves vapor from the cylinder into the system to push liquid outCorrect answer
  • It heats the system so the liquid boils over into the recovery cylinder
  • It runs the system's own compressor to pump down

Why “It moves vapor from the cylinder into the system to push liquid out” is correct

In push-pull, the machine draws vapor off the recovery cylinder, lowering its pressure, and pushes that vapor into the appliance. The pressure difference pushes liquid from the appliance into the cylinder.

Source: EPA: Test Topics

Why the other answers are wrong

  • It pumps liquid directly through its compressor — Push-pull keeps liquid out of the machine's compressor.
  • It heats the system so the liquid boils over into the recovery cylinder — Heating is a separate way to speed recovery.
  • It runs the system's own compressor to pump down — Using the system's compressor is system-dependent recovery, not push-pull.
47. Which recovery machine is a technician required to use on a 300-pound R-410A system?
  • Any machine that reaches 10 inches of Hg
  • Any machine built before November 15, 1993, whatever its rating
  • A system-dependent unit
  • A machine certified for that refrigerant and type of applianceCorrect answer

Why “A machine certified for that refrigerant and type of appliance” is correct

No one may service or dispose of an appliance without using recovery or recycling equipment certified for that type of refrigerant and appliance. It must also be used according to the manufacturer's directions.

Source: 40 CFR 82.154(b); 40 CFR 82.156(g)

Why the other answers are wrong

  • Any machine that reaches 10 inches of Hg — Reaching a vacuum is not enough; the machine must be certified for the job.
  • Any machine built before November 15, 1993, whatever its rating — Only machines certified for the refrigerant and appliance qualify, whatever their age.
  • A system-dependent unit — System-dependent equipment cannot be used on systems over 15 pounds.
48. Near the end of recovering vapor from an R-22 system, recovery slows down. Why?
  • The recovery cylinder is getting colder
  • Lower system pressure means thinner vapor, so less moves per strokeCorrect answer
  • The machine's filter-drier has clogged and stopped flow almost entirely
  • The oil is turning into vapor

Why “Lower system pressure means thinner vapor, so less moves per stroke” is correct

As the system pressure drops, the vapor becomes less dense, so each pump stroke moves less refrigerant. The pressure difference also shrinks as the cylinder fills, so the final stage is the slowest.

Source: EPA: Test Topics

Why the other answers are wrong

  • The recovery cylinder is getting colder — A colder cylinder would speed recovery, not slow it.
  • The machine's filter-drier has clogged and stopped flow almost entirely — A working filter does not usually explain the normal slowdown.
  • The oil is turning into vapor — Oil does not turn into vapor in recovery.

Recovery requirements

49. A technician is replacing the compressor on a very high-pressure appliance that uses R-23, using recovery equipment manufactured in 2019. To what level must the appliance be evacuated before it is opened?
  • 0 inches of Hg vacuumCorrect answer
  • 4 inches of Hg vacuum
  • 10 inches of Hg vacuum
  • 15 inches of Hg vacuum

Why “0 inches of Hg vacuum” is correct

Table 1 sets a single level for very high-pressure appliances: 0 inches of Hg vacuum, whatever the recovery equipment date or charge size. R-23 is one of the examples EPA gives of a very high-pressure refrigerant.

Source: 40 CFR 82.156(a), Table 1; 40 CFR 82.152

Why the other answers are wrong

  • 4 inches of Hg vacuum — 4 inches applies to some medium- and high-pressure rows with pre-1993 equipment, not to very high-pressure appliances.
  • 10 inches of Hg vacuum — 10 inches is for large high-pressure or small medium-pressure appliances with newer equipment.
  • 15 inches of Hg vacuum — 15 inches is only for medium-pressure appliances of 200 pounds or more with newer equipment.
50. An appliance charged with R-508B is being sent for disposal. The only recovery machine on site was manufactured in 1991. What evacuation level does Table 1 require?
  • 4 inches of Hg vacuum
  • 0 inches of Hg vacuumCorrect answer
  • 10 inches of Hg vacuum
  • 25 mm Hg absolute

Why “0 inches of Hg vacuum” is correct

Disposal triggers the same Table 1 levels as opening the appliance. R-508B is a very high-pressure refrigerant, and that row is 0 inches of Hg vacuum for both pre- and post-November 15, 1993 equipment.

Source: 40 CFR 82.156(a), Table 1; 40 CFR 82.152

Why the other answers are wrong

  • 4 inches of Hg vacuum — No very high-pressure row allows or requires 4 inches; the older-equipment column still reads 0.
  • 10 inches of Hg vacuum — 10 inches applies to certain medium- and high-pressure appliances with newer equipment.
  • 25 mm Hg absolute — 25 mm Hg absolute is the level for low-pressure appliances such as R-123 chillers.
51. A packaged rooftop unit holds 150 pounds of R-22. Using recovery equipment made after November 15, 1993, to what level must it be evacuated before the condenser coil is replaced?
  • 4 inches of Hg vacuum
  • 10 inches of Hg vacuum
  • 0 inches of Hg vacuumCorrect answer
  • 15 inches of Hg vacuum

Why “0 inches of Hg vacuum” is correct

R-22 is a high-pressure refrigerant, and a high-pressure appliance with a full charge under 200 pounds must be evacuated to 0 inches of Hg vacuum. That level is the same with older and newer recovery equipment.

Source: 40 CFR 82.156(a), Table 1

Why the other answers are wrong

  • 4 inches of Hg vacuum — 4 inches is the pre-1993 level for high-pressure appliances of 200 pounds or more.
  • 10 inches of Hg vacuum — 10 inches applies once the high-pressure charge reaches 200 pounds, with newer equipment.
  • 15 inches of Hg vacuum — 15 inches is reserved for medium-pressure appliances of 200 pounds or more.
52. A technician recovers R-410A from a split system with a 12-pound charge using a recovery machine built in 1990. What evacuation level must be reached before opening the system for a major repair?
  • 10 inches of Hg vacuum
  • 4 inches of Hg vacuum
  • 25 mm Hg absolute
  • 0 inches of Hg vacuumCorrect answer

Why “0 inches of Hg vacuum” is correct

R-410A is a high-pressure refrigerant, and this appliance holds less than 200 pounds. Table 1 requires 0 inches of Hg vacuum for that row whether the recovery equipment was built before or after November 15, 1993.

Source: 40 CFR 82.156(a), Table 1; 40 CFR 82.152

Why the other answers are wrong

  • 10 inches of Hg vacuum — 10 inches is for high-pressure appliances of 200 pounds or more with newer equipment.
  • 4 inches of Hg vacuum — 4 inches is the older-equipment level for high-pressure appliances of 200 pounds or more, not under 200.
  • 25 mm Hg absolute — 25 mm Hg absolute applies only to low-pressure appliances.
53. A process chiller holds 250 pounds of R-407C. Using recovery equipment manufactured in 2015, what evacuation level is required before a major repair?
  • 0 inches of Hg vacuum
  • 10 inches of Hg vacuumCorrect answer
  • 4 inches of Hg vacuum
  • 15 inches of Hg vacuum

Why “10 inches of Hg vacuum” is correct

R-407C is a high-pressure refrigerant. A high-pressure appliance with a full charge of 200 pounds or more must be pulled to 10 inches of Hg vacuum with equipment made on or after November 15, 1993, or 4 inches with older equipment.

Source: 40 CFR 82.156(a), Table 1; 40 CFR 82.152

Why the other answers are wrong

  • 0 inches of Hg vacuum — 0 inches applies to high-pressure appliances under 200 pounds, and this one holds 250.
  • 4 inches of Hg vacuum — 4 inches is the level for this row only with recovery equipment made before November 15, 1993.
  • 15 inches of Hg vacuum — 15 inches is for medium-pressure appliances of 200 pounds or more, and R-407C is high-pressure.
54. A technician uses a recovery machine built in 1992 on an R-22 system with a 300-pound charge before replacing its evaporator. What level must be reached?
  • 10 inches of Hg vacuum
  • 0 inches of Hg vacuum
  • 4 inches of Hg vacuumCorrect answer
  • 15 inches of Hg vacuum

Why “4 inches of Hg vacuum” is correct

For a high-pressure appliance of 200 pounds or more, Table 1 requires 4 inches of Hg vacuum with recovery equipment made before November 15, 1993. The same appliance would need 10 inches with newer equipment.

Source: 40 CFR 82.156(a), Table 1

Why the other answers are wrong

  • 10 inches of Hg vacuum — 10 inches is the requirement for this row with equipment made on or after November 15, 1993.
  • 0 inches of Hg vacuum — 0 inches applies to high-pressure appliances with less than 200 pounds.
  • 15 inches of Hg vacuum — 15 inches is a medium-pressure requirement for newer equipment.
55. A walk-in cooler system holds 120 pounds of R-134a. Using recovery equipment made in 2010, what evacuation level is required before the compressor is removed?
  • 0 inches of Hg vacuum
  • 4 inches of Hg vacuum
  • 15 inches of Hg vacuum
  • 10 inches of Hg vacuumCorrect answer

Why “10 inches of Hg vacuum” is correct

R-134a is a medium-pressure refrigerant. A medium-pressure appliance under 200 pounds must be evacuated to 10 inches of Hg vacuum with equipment made on or after November 15, 1993, and to 4 inches with older equipment.

Source: 40 CFR 82.156(a), Table 1; 40 CFR 82.152

Why the other answers are wrong

  • 0 inches of Hg vacuum — 0 inches is the level for high-pressure appliances under 200 pounds, but R-134a is medium-pressure.
  • 4 inches of Hg vacuum — 4 inches is this row's requirement only with equipment made before November 15, 1993.
  • 15 inches of Hg vacuum — 15 inches applies when the medium-pressure charge is 200 pounds or more.
56. An older R-12 system with an 80-pound charge is being opened to replace its condenser. The recovery unit was manufactured in 1989. What evacuation level does Table 1 require?
  • 4 inches of Hg vacuumCorrect answer
  • 10 inches of Hg vacuum
  • 0 inches of Hg vacuum
  • 15 inches of Hg vacuum

Why “4 inches of Hg vacuum” is correct

R-12 is a medium-pressure refrigerant. With recovery equipment made before November 15, 1993, every medium-pressure row in Table 1 is 4 inches of Hg vacuum, regardless of charge size.

Source: 40 CFR 82.156(a), Table 1; 40 CFR 82.152

Why the other answers are wrong

  • 10 inches of Hg vacuum — 10 inches is the requirement for a medium-pressure appliance under 200 pounds with newer equipment.
  • 0 inches of Hg vacuum — 0 inches is for very high-pressure and small high-pressure appliances, not medium-pressure.
  • 15 inches of Hg vacuum — 15 inches is for medium-pressure appliances of 200 pounds or more with newer equipment.
57. A comfort-cooling chiller contains 400 pounds of R-134a. Using recovery equipment manufactured in 2021, what evacuation level is required before a major repair?
  • 10 inches of Hg vacuum
  • 15 inches of Hg vacuumCorrect answer
  • 4 inches of Hg vacuum
  • 25 mm Hg absolute

Why “15 inches of Hg vacuum” is correct

R-134a is medium-pressure, and this chiller holds 200 pounds or more. That row requires 15 inches of Hg vacuum with equipment made on or after November 15, 1993, the deepest level for any medium- or high-pressure appliance.

Source: 40 CFR 82.156(a), Table 1; 40 CFR 82.152

Why the other answers are wrong

  • 10 inches of Hg vacuum — 10 inches is the medium-pressure level when the charge is under 200 pounds.
  • 4 inches of Hg vacuum — 4 inches applies only with recovery equipment made before November 15, 1993.
  • 25 mm Hg absolute — 25 mm Hg absolute is for low-pressure appliances; R-134a is medium-pressure.
58. An R-500 system with a 250-pound charge is being retired. The recovery machine was made in 1992. What evacuation level must be reached?
  • 15 inches of Hg vacuum
  • 10 inches of Hg vacuum
  • 4 inches of Hg vacuumCorrect answer
  • 0 inches of Hg vacuum

Why “4 inches of Hg vacuum” is correct

R-500 is listed as a medium-pressure refrigerant. A medium-pressure appliance of 200 pounds or more needs 15 inches with newer equipment, but only 4 inches with equipment made before November 15, 1993. Disposal uses the same table.

Source: 40 CFR 82.156(a), Table 1; 40 CFR 82.152

Why the other answers are wrong

  • 15 inches of Hg vacuum — 15 inches would apply if the recovery machine were made on or after November 15, 1993.
  • 10 inches of Hg vacuum — 10 inches is the newer-equipment level for medium-pressure appliances under 200 pounds.
  • 0 inches of Hg vacuum — 0 inches is not a medium-pressure level in Table 1.
59. A technician is disposing of a 30-pound R-22 rooftop unit using a recovery machine built in 2018. What is the required evacuation level?
  • 0 inches of Hg vacuumCorrect answer
  • 10 inches of Hg vacuum
  • 4 inches of Hg vacuum
  • Recovery of 90 percent of the charge

Why “0 inches of Hg vacuum” is correct

Section 82.156(a) applies the Table 1 levels both before opening and before disposing of an appliance. A high-pressure appliance under 200 pounds must reach 0 inches of Hg vacuum with either age of recovery equipment.

Source: 40 CFR 82.156(a); 40 CFR 82.156(a), Table 1

Why the other answers are wrong

  • 10 inches of Hg vacuum — 10 inches applies to high-pressure appliances of 200 pounds or more.
  • 4 inches of Hg vacuum — 4 inches is a pre-1993 level for larger high-pressure or for medium-pressure appliances.
  • Recovery of 90 percent of the charge — Percentage recovery targets apply to small appliances under 82.156(b), not a 30-pound rooftop unit.
60. A large R-22 system holds 500 pounds in total. The technician isolates a section holding 150 pounds and will open only that section. Using post-1993 recovery equipment, to what level must the isolated section be evacuated?
  • 10 inches of Hg vacuum
  • 4 inches of Hg vacuum
  • 15 inches of Hg vacuum
  • 0 inches of Hg vacuumCorrect answer

Why “0 inches of Hg vacuum” is correct

Table 1 rows apply to a high-pressure appliance or an isolated component of one, based on that component's full charge. A high-pressure isolated component holding less than 200 pounds must be evacuated to 0 inches of Hg vacuum.

Source: 40 CFR 82.156(a), Table 1; 40 CFR 82.156(a)

Why the other answers are wrong

  • 10 inches of Hg vacuum — 10 inches would apply if the isolated component itself held 200 pounds or more.
  • 4 inches of Hg vacuum — 4 inches is a pre-1993 level and does not apply to a high-pressure component under 200 pounds.
  • 15 inches of Hg vacuum — 15 inches is a medium-pressure level; R-22 is high-pressure.
61. A technician will replace a filter-drier on a 60-pound R-22 system. The job is not a major repair and the system will not be evacuated to the atmosphere afterward. What is the minimum evacuation required before opening?
  • To 10 inches of Hg vacuum
  • To 4 inches of Hg vacuum
  • To no higher than 0 psigCorrect answer
  • To no higher than 5 psig

Why “To no higher than 0 psig” is correct

When a repair is not major and is not followed by evacuation of the appliance to the atmosphere, a medium-, high- or very high-pressure appliance only has to be evacuated to no higher than 0 psig before it is opened.

Source: 40 CFR 82.156(a)(1)

Why the other answers are wrong

  • To 10 inches of Hg vacuum — 10 inches is a Table 1 level, which this non-major repair is not required to meet.
  • To 4 inches of Hg vacuum — 4 inches is also a Table 1 level, not the non-major repair requirement.
  • To no higher than 5 psig — 5 psig is the limit for oil changes, not for opening the system to replace a drier.
62. Leaks in an R-22 appliance make it impossible to reach the Table 1 level. What is the highest pressure the leaking component may be at when it is opened?
  • 5 psig
  • 0 psigCorrect answer
  • 10 inches of Hg vacuum
  • 15 psig

Why “0 psig” is correct

When leaks make Table 1 levels unattainable, the leaking component must be evacuated to the lowest level that can be reached without substantially contaminating the refrigerant. That level may not exceed 0 psig.

Source: 40 CFR 82.156(a)(2); EPA: Service Practice Requirements

Why the other answers are wrong

  • 5 psig — 5 psig is the limit for oil changes, not for leaking components.
  • 10 inches of Hg vacuum — 10 inches is a Table 1 level, which the leaking component cannot reach in this case.
  • 15 psig — No rule lets a leaking component be opened above 0 psig.
63. A 220-pound R-22 system has a badly leaking evaporator. The technician can isolate the evaporator from the rest of the system. What must happen to the non-leaking components that will be opened?
  • They may be opened at 0 psig like the leaking part
  • They need no evacuation if they are isolated
  • They must be evacuated to the Table 1 levelCorrect answer
  • They may be opened once liquid is removed

Why “They must be evacuated to the Table 1 level” is correct

The leaky-appliance exception covers only the leaking parts. The technician must isolate leaking from non-leaking components where possible and evacuate the non-leaking components to the full Table 1 levels.

Source: 40 CFR 82.156(a)(2)

Why the other answers are wrong

  • They may be opened at 0 psig like the leaking part — The 0 psig ceiling applies only to the leaking components.
  • They need no evacuation if they are isolated — Isolation does not excuse non-leaking components that are being opened from evacuation.
  • They may be opened once liquid is removed — Removing the liquid is not enough; the components must reach the Table 1 vacuum level.
64. A technician needs to change the compressor oil in a 90-pound R-22 system. To what pressure must the system, or the isolated portion, be brought before the oil is removed?
  • No higher than 0 psig
  • No higher than 15 psig
  • No higher than 10 inches of Hg vacuum
  • No higher than 5 psigCorrect answer

Why “No higher than 5 psig” is correct

For oil changes, the appliance must be evacuated or pressurized to no higher than 5 psig before it is opened, or the oil can be drained into a system receiver brought to that level. Oil holds dissolved refrigerant, so the pressure drop releases it for recovery.

Source: 40 CFR 82.156(a)(1)(iii); EPA: Service Practice Requirements

Why the other answers are wrong

  • No higher than 0 psig — 0 psig is the level for non-major repairs; oil changes have their own 5 psig limit.
  • No higher than 15 psig — 15 psig is above the allowed limit; EPA calls oil changes above 5 psig a violation.
  • No higher than 10 inches of Hg vacuum — 10 inches is a Table 1 level, not the oil-change requirement.
65. Under the definition in 40 CFR 82.152, which of these jobs is a major repair?
  • Replacing the compressorCorrect answer
  • Replacing a Schrader valve core
  • Adding refrigerant through the service port
  • Tightening a flare nut

Why “Replacing the compressor” is correct

A major repair is one that removes the compressor, condenser, evaporator or auxiliary heat exchange coil, or uncovers more than 4 square inches of flow area for more than 15 minutes. Replacing the compressor removes one of the listed components.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Replacing a Schrader valve core — A valve core is not one of the listed components and the opening is tiny.
  • Adding refrigerant through the service port — Adding refrigerant does not remove a component; connecting hoses is not even opening the appliance.
  • Tightening a flare nut — Tightening a fitting removes no listed component.
66. Apart from removing a listed component, a repair counts as major if it uncovers an opening of more than how much flow area, for how long?
  • 2 square inches for more than 30 minutes
  • 4 square inches for more than 15 minutesCorrect answer
  • 4 square inches for more than 60 minutes
  • 8 square inches for more than 15 minutes

Why “4 square inches for more than 15 minutes” is correct

The definition covers any repair that uncovers more than 4 square inches of flow area for more than 15 minutes. That much open area for that long lets in enough air and moisture to treat the job like a component replacement.

Source: 40 CFR 82.152

Why the other answers are wrong

  • 2 square inches for more than 30 minutes — Both numbers are wrong; the rule is 4 square inches and 15 minutes.
  • 4 square inches for more than 60 minutes — The time limit is 15 minutes, not an hour.
  • 8 square inches for more than 15 minutes — The area limit is 4 square inches, not 8.
67. Which of these repairs on a 70-pound R-410A system is not a major repair, assuming the opening is small and brief?
  • Replacing the evaporator coil
  • Replacing the condenser coil
  • Replacing the expansion valveCorrect answer
  • Replacing the compressor

Why “Replacing the expansion valve” is correct

Only removal of the compressor, condenser, evaporator or auxiliary heat exchange coil, or a large and long opening, makes a repair major. A thermostatic expansion valve is not on that list, so swapping it with a small, brief opening is non-major.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Replacing the evaporator coil — The evaporator is one of the four listed components.
  • Replacing the condenser coil — The condenser is one of the four listed components.
  • Replacing the compressor — The compressor is one of the four listed components.
68. What is the largest full charge on which system-dependent recovery equipment may be used, unless it is a permanently attached pump-out unit?
  • 5 pounds
  • 50 pounds
  • 200 pounds
  • 15 poundsCorrect answer

Why “15 pounds” is correct

System-dependent equipment relies on the appliance's own compressor or pressure. It may not be used on appliances with a full charge of more than 15 pounds unless it is permanently attached as a pump-out unit.

Source: 40 CFR 82.156(e)

Why the other answers are wrong

  • 5 pounds — 5 pounds is the small-appliance limit, not the system-dependent limit.
  • 50 pounds — 50 pounds is the leak repair threshold under Part 82.
  • 200 pounds — 200 pounds splits rows of Table 1; it is not the system-dependent limit.
69. A 40-pound R-22 system needs refrigerant removed. In which case may system-dependent recovery equipment be used on it?
  • When the system's own compressor is still running normally
  • When the job is not a major repair
  • When the recovery cylinder is chilled
  • When it is permanently attached as a pump-out unitCorrect answer

Why “When it is permanently attached as a pump-out unit” is correct

Above 15 pounds, system-dependent equipment is banned unless it is permanently attached to the appliance as a pump-out unit. A working compressor or a non-major job does not create an exception.

Source: 40 CFR 82.156(e)

Why the other answers are wrong

  • When the system's own compressor is still running normally — A working compressor helps system-dependent recovery but does not lift the 15-pound limit.
  • When the job is not a major repair — The 15-pound limit applies to all jobs, major or not.
  • When the recovery cylinder is chilled — Chilling the cylinder speeds recovery but has nothing to do with the rule.
70. After recovering R-22 from a 100-pound system for a compressor change, what must the technician do before opening it?
  • Verify the required evacuation level was reachedCorrect answer
  • Add nitrogen to bring the pressure back above 0 psig
  • Have the owner sign a recovery record
  • Wait 24 hours for the oil to settle

Why “Verify the required evacuation level was reached” is correct

Section 82.156(a) requires the technician to verify that the applicable evacuation level has been reached in the appliance or the part before it is opened. Watching the gauge for a few minutes after shutting off the machine is part of that check.

Source: 40 CFR 82.156(a)

Why the other answers are wrong

  • Add nitrogen to bring the pressure back above 0 psig — Adding nitrogen is not required before opening a high-pressure appliance and would not confirm recovery.
  • Have the owner sign a recovery record — No owner signature is required before opening the system.
  • Wait 24 hours for the oil to settle — No waiting period of that kind exists in the rule.
71. An R-22 system has service valves that let the technician pump the charge into the receiver and isolate it there. What does the rule allow?
  • Venting the small amount left in the open section
  • Opening the section without any further checks
  • Evacuating only the part being servicedCorrect answer
  • Skipping evacuation if the job is under 15 minutes

Why “Evacuating only the part being serviced” is correct

Technicians may evacuate either the whole appliance or just the part to be serviced, if the refrigerant in that part can be isolated to a system receiver. The part being opened must still reach the required level, and that must be verified.

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

Why the other answers are wrong

  • Venting the small amount left in the open section — Venting any refrigerant from the open section is prohibited.
  • Opening the section without any further checks — The isolated part still has to be evacuated to the required level and verified.
  • Skipping evacuation if the job is under 15 minutes — A short job does not remove the evacuation requirement.
72. Which activity is not considered opening an appliance under 40 CFR 82.152?
  • Cutting a refrigerant line to replace a drier
  • Removing a leaking service valve
  • Unbrazing a condenser coil
  • Connecting gauges to measure pressuresCorrect answer

Why “Connecting gauges to measure pressures” is correct

Opening an appliance means any service that would release refrigerant to the atmosphere. The definition says connecting and disconnecting hoses and gauges to measure pressures, add refrigerant or recover refrigerant is not opening an appliance.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Cutting a refrigerant line to replace a drier — Cutting a line exposes the refrigerant circuit and is opening the appliance.
  • Removing a leaking service valve — Removing a valve exposes the circuit to the atmosphere.
  • Unbrazing a condenser coil — Unbrazing a coil opens the refrigerant circuit.
73. Which technician certification is required to service a 150-pound R-134a chiller, a medium-pressure appliance?
  • Type I
  • Type IICorrect answer
  • Type III
  • No certification is needed

Why “Type II” is correct

Type II certification covers medium-, high- and very high-pressure appliances other than small appliances and motor vehicle air conditioners. R-134a is a medium-pressure refrigerant, so this chiller is Type II work.

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

Why the other answers are wrong

  • Type I — Type I covers only small appliances with 5 pounds or less.
  • Type III — Type III covers low-pressure appliances such as R-123 chillers.
  • No certification is needed — Anyone who opens this circuit must be certified.
74. Table 1 gives different vacuum levels for equipment made before and after November 15, 1993. Which piece of equipment does that date refer to?
  • The appliance being serviced
  • The vacuum gauge used to check the level
  • The refrigerant cylinder
  • The recovery or recycling equipmentCorrect answer

Why “The recovery or recycling equipment” is correct

The Table 1 columns are labelled by when the recovery and/or recycling equipment was manufactured or imported. The age of the appliance being serviced does not change the required level.

Source: 40 CFR 82.156(a), Table 1

Why the other answers are wrong

  • The appliance being serviced — The appliance's age is not used to pick the Table 1 column.
  • The vacuum gauge used to check the level — The gauge's age plays no part in the rule.
  • The refrigerant cylinder — Cylinder dates relate to DOT requalification, not evacuation levels.

Refrigeration

75. A technician arrives at an unfamiliar packaged unit and needs to know which refrigerant it uses. Where should they look first?
  • The color of the suction line insulation
  • The unit's nameplateCorrect answer
  • The size of the service valves
  • The thermostat model

Why “The unit's nameplate” is correct

The nameplate lists the refrigerant the appliance was built for, and usually its charge. Checking it first prevents mixing refrigerants or using the wrong recovery cylinder.

Source: EPA: Test Topics

Why the other answers are wrong

  • The color of the suction line insulation — Insulation color says nothing about the refrigerant.
  • The size of the service valves — Valve size does not identify the refrigerant.
  • The thermostat model — The thermostat has no connection to the refrigerant type.
76. A suction gauge reads 100 psig. What is that pressure in psia?
  • 85.3 psia
  • 100 psia
  • 114.7 psiaCorrect answer
  • 129.4 psia

Why “114.7 psia” is correct

Gauges read pressure above the atmosphere, so absolute pressure is gauge pressure plus 14.7 psi at sea level. 100 + 14.7 = 114.7 psia.

Source: EPA: Test Topics

Why the other answers are wrong

  • 85.3 psia — This subtracts 14.7 instead of adding it.
  • 100 psia — psig and psia differ by atmospheric pressure, so they are not equal.
  • 129.4 psia — This adds 14.7 twice.
77. A pressure-temperature table lists a saturation pressure of 250 psia. What would a gauge read at that pressure?
  • 235.3 psigCorrect answer
  • 250 psig
  • 264.7 psig
  • 279.4 psig

Why “235.3 psig” is correct

To convert absolute pressure to gauge pressure, subtract 14.7. 250 - 14.7 = 235.3 psig.

Source: EPA: Test Topics

Why the other answers are wrong

  • 250 psig — Gauge and absolute pressure are not the same number.
  • 264.7 psig — This adds 14.7 when it should be subtracted.
  • 279.4 psig — This adds 14.7 twice.
78. A refrigerant has a liquid-phase saturation pressure of 200 psia at 104 °F. How does 40 CFR 82.152 classify an appliance that uses it?
  • Low-pressure
  • Medium-pressure
  • Very high-pressure
  • High-pressureCorrect answer

Why “High-pressure” is correct

A high-pressure appliance uses a refrigerant with a saturation pressure between 170 and 355 psia at 104 °F. 200 psia falls in that range, alongside refrigerants such as R-22 and R-410A.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Low-pressure — Low-pressure means below 45 psia at 104 °F.
  • Medium-pressure — Medium-pressure covers 45 to 170 psia at 104 °F.
  • Very high-pressure — Very high-pressure means above 355 psia, or a critical temperature below 104 °F.
79. Under the 40 CFR 82.152 definitions, an appliance using R-134a is which kind of appliance?
  • Low-pressure
  • Medium-pressureCorrect answer
  • High-pressure
  • Very high-pressure

Why “Medium-pressure” is correct

Medium-pressure appliances use a refrigerant with a saturation pressure between 45 and 170 psia at 104 °F. EPA's examples include R-134a, R-12, R-114, R-124 and R-500.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Low-pressure — Low-pressure examples are R-11, R-123, R-113 and R-245fa.
  • High-pressure — High-pressure examples are R-22, R-407A, R-407C, R-410A and R-502.
  • Very high-pressure — Very high-pressure examples are R-13, R-23, R-503, R-508A and R-508B.
80. A laboratory freezer cascade stage uses R-23. Which pressure class is it?
  • Very high-pressureCorrect answer
  • High-pressure
  • Medium-pressure
  • Low-pressure

Why “Very high-pressure” is correct

R-23 is one of EPA's examples of a very high-pressure refrigerant, along with R-13, R-503, R-508A and R-508B. Very high-pressure appliances, other than small appliances, are Type II work.

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

Why the other answers are wrong

  • High-pressure — High-pressure examples include R-22 and R-410A, not R-23.
  • Medium-pressure — Medium-pressure examples include R-134a and R-12.
  • Low-pressure — Low-pressure examples include R-123 and R-11.
81. A refrigerant's critical temperature is below 104 °F. How is an appliance using it classified?
  • Medium-pressure
  • High-pressure
  • Very high-pressureCorrect answer
  • Low-pressure

Why “Very high-pressure” is correct

The very high-pressure definition covers refrigerants with a critical temperature below 104 °F or a saturation pressure above 355 psia at 104 °F. Above its critical temperature a refrigerant cannot exist as a liquid, so it cannot be rated by saturation pressure there.

Source: 40 CFR 82.152

Why the other answers are wrong

  • Medium-pressure — Medium-pressure is defined by a saturation pressure of 45 to 170 psia.
  • High-pressure — High-pressure is defined by a saturation pressure of 170 to 355 psia.
  • Low-pressure — Low-pressure refrigerants have saturation pressures below 45 psia.
82. In an operating R-22 system, what is in the receiver?
  • Low-pressure vapor
  • High-pressure liquidCorrect answer
  • A low-pressure liquid and vapor mix
  • High-pressure superheated vapor

Why “High-pressure liquid” is correct

The receiver sits after the condenser and stores the high-pressure liquid that comes out of it. That is why it is a good place to start liquid recovery.

Source: EPA: Test Topics

Why the other answers are wrong

  • Low-pressure vapor — Low-pressure vapor is found in the suction line.
  • A low-pressure liquid and vapor mix — A low-pressure mix leaves the metering device.
  • High-pressure superheated vapor — Superheated high-pressure vapor is in the discharge line.
83. What is the job of a suction line accumulator in a heat pump using R-410A?
  • To store high-pressure liquid for the metering device
  • To remove moisture from the liquid line
  • To raise the discharge pressure
  • To trap liquid so it does not reach the compressorCorrect answer

Why “To trap liquid so it does not reach the compressor” is correct

The accumulator sits in the suction line, on the low-pressure side. It catches liquid refrigerant that leaves the evaporator and lets only vapor return, protecting the compressor from liquid slugging.

Source: EPA: Test Topics

Why the other answers are wrong

  • To store high-pressure liquid for the metering device — Storing high-pressure liquid is the receiver's job.
  • To remove moisture from the liquid line — Removing moisture is the filter-drier's job.
  • To raise the discharge pressure — The accumulator does not raise discharge pressure.
84. What happens to the refrigerant inside the evaporator of an R-410A system?
  • Low-pressure liquid boils into vapor as it absorbs heatCorrect answer
  • High-pressure vapor condenses into liquid
  • Vapor is compressed to a higher pressure
  • Liquid is subcooled before it reaches the metering device

Why “Low-pressure liquid boils into vapor as it absorbs heat” is correct

In the evaporator, low-pressure refrigerant boils from liquid into vapor as it absorbs heat from the air or water being cooled. That is where the cooling happens.

Source: EPA: Test Topics

Why the other answers are wrong

  • High-pressure vapor condenses into liquid — Condensing happens in the condenser.
  • Vapor is compressed to a higher pressure — Compression happens in the compressor.
  • Liquid is subcooled before it reaches the metering device — Subcooling happens at the end of the condenser.
85. In the condenser of an R-22 system, the refrigerant:
  • boils from liquid to vapor at low pressure as it absorbs heat
  • gives up heat and changes from high-pressure vapor to liquidCorrect answer
  • is throttled to a lower pressure
  • stays as low-pressure vapor

Why “gives up heat and changes from high-pressure vapor to liquid” is correct

Hot, high-pressure vapor from the compressor enters the condenser and rejects heat. It condenses into high-pressure liquid, which may be slightly subcooled when it leaves.

Source: EPA: Test Topics

Why the other answers are wrong

  • boils from liquid to vapor at low pressure as it absorbs heat — Boiling at low pressure happens in the evaporator.
  • is throttled to a lower pressure — Throttling happens at the metering device.
  • stays as low-pressure vapor — Low-pressure vapor belongs in the suction line.
86. What is in the discharge line between the compressor and condenser of an R-407C system?
  • Low-pressure saturated vapor
  • High-pressure subcooled liquid
  • High-pressure superheated vaporCorrect answer
  • Low-pressure liquid and vapor mix

Why “High-pressure superheated vapor” is correct

The compressor raises the pressure and temperature of the suction vapor. The discharge line carries that hot, high-pressure superheated vapor to the condenser.

Source: EPA: Test Topics

Why the other answers are wrong

  • Low-pressure saturated vapor — Low-pressure vapor is on the suction side.
  • High-pressure subcooled liquid — Subcooled liquid leaves the condenser, not the compressor.
  • Low-pressure liquid and vapor mix — A low-pressure mix leaves the metering device.
87. What leaves the metering device in an operating R-22 system?
  • High-pressure liquid
  • High-pressure vapor
  • Low-pressure superheated vapor, the same as the suction line
  • A low-pressure mix of liquid and vaporCorrect answer

Why “A low-pressure mix of liquid and vapor” is correct

The metering device drops the pressure of the high-pressure liquid. Some of it flashes to vapor, so a cold, low-pressure mix of liquid and vapor enters the evaporator.

Source: EPA: Test Topics

Why the other answers are wrong

  • High-pressure liquid — High-pressure liquid enters the metering device; it does not leave it.
  • High-pressure vapor — High-pressure vapor is in the discharge line.
  • Low-pressure superheated vapor, the same as the suction line — Superheated low-pressure vapor leaves the evaporator.
88. In normal operation, what should be in the suction line returning to the compressor of an R-410A system?
  • Low-pressure vaporCorrect answer
  • High-pressure liquid
  • High-pressure vapor
  • Low-pressure liquid

Why “Low-pressure vapor” is correct

The suction line carries low-pressure vapor from the evaporator back to the compressor. Liquid there can damage the compressor, which is why accumulators are fitted.

Source: EPA: Test Topics

Why the other answers are wrong

  • High-pressure liquid — High-pressure liquid is in the liquid line and receiver.
  • High-pressure vapor — High-pressure vapor is in the discharge line.
  • Low-pressure liquid — Liquid returning to the compressor is a fault, not normal operation.
89. An owner asks to convert an R-22 split system to propane or another hydrocarbon. What should the technician know?
  • Hydrocarbons are approved drop-ins for R-22
  • Hydrocarbons are approved for retrofits if the oil is changed
  • Hydrocarbons are not approved for retrofitting these systemsCorrect answer
  • Hydrocarbons are approved for retrofits under 50 pounds

Why “Hydrocarbons are not approved for retrofitting these systems” is correct

EPA's test outline states that hydrocarbons are not approved for retrofits. Retrofitting means converting an existing appliance from one refrigerant to another, and an R-22 system was never designed for a flammable refrigerant.

Source: EPA: Test Topics; 40 CFR 82.152

Why the other answers are wrong

  • Hydrocarbons are approved drop-ins for R-22 — No hydrocarbon is an approved drop-in for R-22 equipment.
  • Hydrocarbons are approved for retrofits if the oil is changed — Changing the oil does not make a hydrocarbon retrofit approved.
  • Hydrocarbons are approved for retrofits under 50 pounds — Charge size does not create an approval for hydrocarbon retrofits.
90. An idle R-22 system with both liquid and vapor inside has been sitting in a 75 °F room. What does its pressure tell the technician?
  • Nothing, because idle pressure is random
  • The saturation pressure of R-22 at about 75 °FCorrect answer
  • The amount of refrigerant in the system
  • The pressure the compressor produced the last time it ran

Why “The saturation pressure of R-22 at about 75 °F” is correct

When liquid and vapor sit together at the same temperature, the pressure equals the refrigerant's saturation pressure at that temperature. Comparing the reading with a pressure-temperature chart can confirm the refrigerant or reveal non-condensables.

Source: EPA: Test Topics

Why the other answers are wrong

  • Nothing, because idle pressure is random — Idle pressure follows the pressure-temperature relationship, not chance.
  • The amount of refrigerant in the system — Pressure in a saturated system does not show how much refrigerant is present.
  • The pressure the compressor produced the last time it ran — Once idle, the pressures equalize to the saturation pressure.

Safety

91. An R-410A system has just been evacuated to a deep vacuum after a repair. Why should the hermetic compressor not be started yet?
  • Running it under vacuum can damage the motorCorrect answer
  • It will cool the system too fast
  • It will void the recovery machine's certification
  • It will raise the system's superheat

Why “Running it under vacuum can damage the motor” is correct

EPA's outline says hermetic compressors should not be energized under vacuum. In a deep vacuum the motor windings lose the insulating effect of the surrounding gas, and the motor can arc and burn out.

Source: EPA: Test Topics

Why the other answers are wrong

  • It will cool the system too fast — Cooling speed is not the hazard.
  • It will void the recovery machine's certification — Recovery machine certification is not affected.
  • It will raise the system's superheat — Superheat is not what makes this dangerous.
92. What is the main risk of energizing a hermetic compressor while the system is in a deep vacuum?
  • The oil will freeze
  • The refrigerant will decompose into acids and sludge
  • The suction line will collapse
  • Breakdown of the motor winding insulationCorrect answer

Why “Breakdown of the motor winding insulation” is correct

With almost no gas around the windings, the insulation can break down and the motor can short or arc. That can burn out the motor of a hermetic compressor, which sits inside the sealed shell.

Source: EPA: Test Topics

Why the other answers are wrong

  • The oil will freeze — Oil does not freeze from running in a vacuum.
  • The refrigerant will decompose into acids and sludge — There is almost no refrigerant left in a deep vacuum to decompose.
  • The suction line will collapse — Copper suction lines do not collapse under vacuum.
93. After evacuating an R-22 system, a technician wants to check that the hermetic compressor runs. What should be done first?
  • Start it for a few seconds to listen for noise
  • Pull the vacuum deeper
  • Break the vacuum by charging refrigerantCorrect answer
  • Disconnect the crankcase heater

Why “Break the vacuum by charging refrigerant” is correct

A hermetic compressor should not be energized while the system is in a vacuum. Breaking the vacuum by charging refrigerant first removes the risk of motor damage.

Source: EPA: Test Topics

Why the other answers are wrong

  • Start it for a few seconds to listen for noise — Starting it under vacuum is exactly what should be avoided.
  • Pull the vacuum deeper — A deeper vacuum makes the risk worse, not better.
  • Disconnect the crankcase heater — The crankcase heater does not address the vacuum hazard.
94. According to EPA's Type II test outline, which sensor does ASHRAE Standard 15 require in equipment rooms, whatever the refrigerant?
  • A smoke detector
  • A carbon monoxide detector near the door
  • A humidity sensor
  • An oxygen deprivation sensorCorrect answer

Why “An oxygen deprivation sensor” is correct

EPA's outline lists an oxygen deprivation sensor in equipment rooms, with all refrigerants, as an ASHRAE Standard 15 requirement, and that is the answer on the 608 test. That wording dates from the 1992 edition. Current Standard 15 instead requires a refrigerant detector in every machinery room that alarms and starts ventilation at or below the refrigerant's occupational exposure limit.

Source: EPA: Test Topics; ASHRAE Interpretation IC 15-1992-11 (oxygen sensor wording, 1994); ASHRAE 15-2016 Addendum c (detector set point at OEL)

Why the other answers are wrong

  • A smoke detector — Smoke detection is a fire code matter, not the ASHRAE 15 item EPA lists.
  • A carbon monoxide detector near the door — Carbon monoxide is not what a refrigerant leak produces.
  • A humidity sensor — Humidity sensors are not a safety requirement for refrigerant leaks.
95. Why can a large R-134a leak in an enclosed equipment room be dangerous even though R-134a has low toxicity?
  • R-134a burns easily in air
  • R-134a turns into carbon monoxide
  • Its heavy vapor can displace the oxygen in the roomCorrect answer
  • R-134a reacts with oxygen in the room to form ozone

Why “Its heavy vapor can displace the oxygen in the room” is correct

Most refrigerant vapors are heavier than air. A major leak can collect in an enclosed room and push out the oxygen, which can cause suffocation without warning. That is the hazard behind EPA's oxygen-deprivation topic; current ASHRAE Standard 15 guards against it with a refrigerant detector set no higher than the refrigerant's exposure limit (1,000 ppm for R-134a).

Source: EPA: Test Topics; ASHRAE 15-2016 Addendum c (detector set point at OEL)

Why the other answers are wrong

  • R-134a burns easily in air — R-134a is not classed as a flammable refrigerant.
  • R-134a turns into carbon monoxide — R-134a does not turn into carbon monoxide.
  • R-134a reacts with oxygen in the room to form ozone — Refrigerants do not create ozone by reacting with oxygen.
96. A technician is pressurizing an R-22 system with nitrogen for a leak test. What must be used between the nitrogen cylinder and the system?
  • A pressure regulatorCorrect answer
  • A recovery machine
  • A filter-drier
  • A sight glass

Why “A pressure regulator” is correct

A full nitrogen cylinder holds far more pressure than any refrigeration system can safely take. A pressure regulator limits the pressure fed to the system, and a relief valve downstream adds protection.

Source: EPA: Test Topics

Why the other answers are wrong

  • A recovery machine — A recovery machine is not used to pressurize with nitrogen.
  • A filter-drier — A filter-drier does not control pressure.
  • A sight glass — A sight glass does not control pressure.
97. Why must oxygen never be used to pressurize a refrigeration system for leak testing?
  • It reacts with the refrigerant to form hydrochloric acid
  • It can explode in contact with compressor oilCorrect answer
  • It leaks out too fast to measure
  • It is not detectable by any test

Why “It can explode in contact with compressor oil” is correct

Oxygen under pressure can ignite or explode when it meets oil, and every system contains compressor oil. Dry nitrogen is the safe choice for pressure testing.

Source: EPA: Test Topics

Why the other answers are wrong

  • It reacts with the refrigerant to form hydrochloric acid — The danger is combustion with oil, not acid.
  • It leaks out too fast to measure — Leak rate is not the reason oxygen is forbidden.
  • It is not detectable by any test — Detectability is not the problem; the explosion risk is.
98. How high may nitrogen pressure go when leak testing the low side of an R-410A system?
  • To the full nitrogen cylinder pressure
  • To twice the high-side pressure seen in normal operation
  • No higher than the test pressure on the nameplateCorrect answer
  • To any pressure if a regulator is used

Why “No higher than the test pressure on the nameplate” is correct

The nameplate gives the design or test pressures for the system. Exceeding them can rupture components, so the regulator should be set no higher than the nameplate test pressure.

Source: EPA: Test Topics

Why the other answers are wrong

  • To the full nitrogen cylinder pressure — Full cylinder pressure would far exceed what the system can take.
  • To twice the high-side pressure seen in normal operation — There is no general rule of twice operating pressure.
  • To any pressure if a regulator is used — A regulator only helps if it is set to a safe pressure.
99. A technician is recovering liquid R-22 from a 250-pound system. What protective equipment is most important against liquid refrigerant spray?
  • Hearing protection
  • A hard hat
  • Steel-toe boots and a hard hat
  • Safety glasses and glovesCorrect answer

Why “Safety glasses and gloves” is correct

Liquid refrigerant boils off at very low temperatures when released and can freeze skin and eyes on contact. Safety glasses and gloves protect against frostbite from a hose or fitting that sprays.

Source: EPA: Test Topics

Why the other answers are wrong

  • Hearing protection — Hearing protection does not guard against liquid refrigerant contact.
  • A hard hat — A hard hat does not protect eyes or hands from liquid refrigerant.
  • Steel-toe boots and a hard hat — Boots do not protect eyes or hands.
100. Does the equipment room oxygen deprivation requirement in EPA's test outline apply when the chiller uses an HFC rather than a CFC or HCFC?
  • Yes, it applies with all refrigerantsCorrect answer
  • No, it applies only to CFCs
  • No, it applies only to flammable refrigerants
  • Only if the room has no windows

Why “Yes, it applies with all refrigerants” is correct

EPA's outline specifies an oxygen deprivation sensor with all refrigerants. Any refrigerant vapor that fills an enclosed room can displace oxygen, whether it depletes ozone or not. Current ASHRAE Standard 15 also covers every refrigerant, but with a refrigerant detector set at or below its exposure limit rather than an oxygen sensor.

Source: EPA: Test Topics; ASHRAE Interpretation IC 15-1992-11 (oxygen sensor wording, 1994); ASHRAE 15-2016 Addendum c (detector set point at OEL)

Why the other answers are wrong

  • No, it applies only to CFCs — The outline says all refrigerants, not just CFCs.
  • No, it applies only to flammable refrigerants — The concern is oxygen displacement, which any refrigerant can cause.
  • Only if the room has no windows — Windows are not an exemption in the outline.

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.