EPA 608 Type III mock exam
Core plus Type III, 50 questions: the test you take for Type III certification.
Before you start
- 50 questions: 25 Core and 25 Type 3.
- Each section is scored on its own. On the real exam you need 70% in a section to pass it, and the results page shows your score against that mark.
- None of these questions appear on the practice pages, so this is a fair check of what you know.
- One question per page, with the answer and explanation shown as you go. No timer and no sign-up; your answers are saved in this browser so you can stop and come back.
What this test covers
- Core: Ozone depletion, the Clean Air Act, Section 608 rules, the three Rs, recovery basics, safety and shipping. Every 608 test includes 25 Core questions. Practice Core questions.
- Type III: Low-pressure appliances, mainly centrifugal chillers using refrigerants like R-123 and R-11. Practice Type 3 questions.
Answer key: every answer, explained
Take the test first: the answers are here for checking afterwards. Each one says why it is right, why each other choice is wrong, and which rule it comes from.
Core
1. An older centrifugal chiller is charged with R-11. What type of refrigerant is R-11?
- HFC
- HCFC
- HFO
- CFCCorrect answer
Why “CFC” is correct
R-11 is a chlorofluorocarbon, and it is the reference refrigerant for ozone depletion potential with an ODP of 1.0. Its replacement in many chillers, R-123, is an HCFC.
Source: EPA: Test Topics
Why the other answers are wrong
- HFC — HFCs contain no chlorine; R-11 does.
- HCFC — R-123, not R-11, is the HCFC used in many newer low-pressure chillers.
- HFO — HFOs are recent low-GWP refrigerants, not R-11.
2. R-123 replaced R-11 in many low-pressure chillers. How is R-123 classified?
- HCFCCorrect answer
- CFC
- HFC
- Hydrocarbon
Why “HCFC” is correct
R-123 is a hydrochlorofluorocarbon. It contains chlorine and so still depletes ozone, but far less than the CFC R-11 it replaced. Like other HCFCs, it is being phased out.
Source: EPA: Test Topics
Why the other answers are wrong
- CFC — R-11 is the CFC; R-123 contains hydrogen as well.
- HFC — R-123 contains chlorine, so it is not an HFC.
- Hydrocarbon — R-123 contains chlorine and fluorine, so it is not a hydrocarbon.
3. What range of ozone depletion potential do HCFC refrigerants fall in, compared with CFC-11 at 1.0?
- About 0.01 to 0.1Correct answer
- About 0.6 to 1.0
- About 1.0 to 10
- Exactly zero
Why “About 0.01 to 0.1” is correct
HCFCs have ODPs of roughly 0.01 to 0.1. They still contain chlorine, but much of each molecule breaks down in the lower atmosphere before it reaches the stratosphere. The highest-ODP HCFCs were phased out first.
Source: EPA: Test Topics
Why the other answers are wrong
- About 0.6 to 1.0 — 0.6 to 1.0 is the range of the common CFCs.
- About 1.0 to 10 — ODPs up to 10 belong to the halons, not HCFCs.
- Exactly zero — An ODP of zero belongs to HFCs, which contain no chlorine.
4. Which part of the Clean Air Act directs EPA to protect the stratospheric ozone layer, including rules on recycling refrigerants?
- Title I
- Title IV
- Title VICorrect answer
- Title IX
Why “Title VI” is correct
Title VI of the Clean Air Act, added in the 1990 amendments, directs EPA to protect stratospheric ozone. It covers production of ozone-depleting substances, the recycling and handling of refrigerants, and the evaluation of substitutes. Section 608 is part of Title VI.
Source: EPA: Test Topics
Why the other answers are wrong
- Title I — Title I deals with ground-level air quality standards.
- Title IV — Title IV deals with acid rain.
- Title IX — There is no Title IX ozone program in the Clean Air Act.
5. A building owner who is not a technician opens a valve and releases R-410A from his own rooftop unit. Does the venting prohibition apply to him?
- No, it applies only to certified technicians
- Yes, it applies to anyone servicing or disposing of oneCorrect answer
- No, owners may do what they want with their own equipment
- Yes, but only if the unit holds more than 50 pounds
Why “Yes, it applies to anyone servicing or disposing of one” is correct
40 CFR 82.154(a)(1) says no person maintaining, servicing, repairing or disposing of an appliance may knowingly vent refrigerant. "Person" includes individuals and companies, so the rule applies to owners as well as technicians.
Source: 40 CFR 82.154(a)(1); 40 CFR 82.152
Why the other answers are wrong
- No, it applies only to certified technicians — The prohibition covers every person, not just certified technicians.
- No, owners may do what they want with their own equipment — Owning the equipment does not give permission to vent.
- Yes, but only if the unit holds more than 50 pounds — The venting prohibition has no charge-size threshold.
6. Under 40 CFR 82.152, which of these is not considered "opening an appliance"?
- Removing a compressor for replacement
- Connecting hoses and gauges to measure pressureCorrect answer
- Cutting a refrigerant line to replace a drier
- Unbrazing a condenser coil
Why “Connecting hoses and gauges to measure pressure” is correct
The definition of opening an appliance covers service that would release refrigerant to the atmosphere. Connecting and disconnecting hoses and gauges to measure pressures, add refrigerant or recover refrigerant is specifically not "opening," though it still requires certification.
Source: 40 CFR 82.152
Why the other answers are wrong
- Removing a compressor for replacement — Removing a compressor exposes the refrigerant circuit and is opening the appliance.
- Cutting a refrigerant line to replace a drier — Cutting a line opens the refrigerant circuit.
- Unbrazing a condenser coil — Unbrazing a coil opens the refrigerant circuit.
7. Under 40 CFR 82.154(e), a new small appliance sold in the U.S. must come with what feature to make recovery possible?
- A pressure relief valve
- A sight glass
- A permanently attached recovery unit
- A process stubCorrect answer
Why “A process stub” is correct
New small appliances must have a process stub, a length of tubing that gives access to the refrigerant and can be resealed. Larger appliances must have a servicing aperture. Both make recovery at service and disposal possible.
Source: 40 CFR 82.154(e); 40 CFR 82.152
Why the other answers are wrong
- A pressure relief valve — Relief valves protect against overpressure but are not the required access point.
- A sight glass — A sight glass shows liquid flow and is not required for recovery.
- A permanently attached recovery unit — Permanently attached recovery units are not required.
8. A refrigerant wholesaler sells R-454B to a contractor. Which records must the wholesaler keep, and for how long?
- The address of the appliance being serviced, for five years
- The technician's test score, for one year
- Invoices with buyer, date and quantity, for three yearsCorrect answer
- No records, because R-454B is a substitute
Why “Invoices with buyer, date and quantity, for three years” is correct
Under 40 CFR 82.154(c)(3), sellers of class I, class II and non-exempt substitute refrigerants must keep invoices showing the purchaser's name, the date of sale and the quantity sold, plus any proof of a certified employee, for three years.
Source: 40 CFR 82.154(c)(3)
Why the other answers are wrong
- The address of the appliance being serviced, for five years — The wholesaler does not have to record where the refrigerant will be used.
- The technician's test score, for one year — Test scores are kept by certifying programs, not wholesalers.
- No records, because R-454B is a substitute — Non-exempt substitutes have been covered by the sales restriction since January 1, 2018.
9. After taking the Section 608 test, how soon must the certifying program send the results?
- Within 7 days
- Within 30 daysCorrect answer
- Within 90 days
- Within one year
Why “Within 30 days” is correct
Appendix D requires certifying programs to give applicants their results no later than 30 days from the test date and to issue the wallet card within 30 days. For mail-in Type I tests the 30 days run from when the program receives the completed test.
Source: 40 CFR Part 82, Subpart F, Appendix D; EPA: Section 608 Q&A
Why the other answers are wrong
- Within 7 days — Seven days is not the deadline in the rule.
- Within 90 days — Ninety days is longer than the rule allows.
- Within one year — One year is far longer than the 30-day deadline.
10. A technician wants to service small appliances, high-pressure systems and low-pressure chillers. Which certification covers all of them?
- Type II
- Type III
- UniversalCorrect answer
- Core only
Why “Universal” is correct
Universal certification covers everything that Types I, II and III cover. It requires passing Core and all three type sections under closed-book, proctored conditions, either in one sitting or by combining separate passing scores.
Source: 40 CFR 82.161(a)(1); 40 CFR Part 82, Subpart F, Appendix D
Why the other answers are wrong
- Type II — Type II does not cover small appliances or low-pressure chillers.
- Type III — Type III covers only low-pressure appliances.
- Core only — Core alone does not certify a technician for any equipment.
11. A technician plans to convert an R-22 system to a substitute refrigerant. What must be done with the R-22 first?
- Recover it with certified recovery equipmentCorrect answer
- Vent it, since R-22 is being phased out
- Leave it in and add the substitute on top
- Mix it with the substitute in a cylinder
Why “Recover it with certified recovery equipment” is correct
The existing charge must be recovered before the system is opened for a retrofit. The new refrigerant's lubricant and component requirements are then followed, because a retrofit is not a simple drop-in.
Source: 40 CFR 82.154(a); 40 CFR 82.152
Why the other answers are wrong
- Vent it, since R-22 is being phased out — Venting R-22 is a violation, phaseout or not.
- Leave it in and add the substitute on top — Adding a substitute on top creates a mixture of unknown composition.
- Mix it with the substitute in a cylinder — Mixing refrigerants makes them hard or impossible to reclaim.
12. Which lubricant was traditionally used in R-12 CFC refrigeration systems?
- Silicone oil
- Polyolester oil
- Polyalkylene glycol oil
- Mineral oilCorrect answer
Why “Mineral oil” is correct
CFC systems such as those using R-12 traditionally used mineral oil. Many substitute refrigerants, including HFCs, do not mix with mineral oil, which is why retrofits often require an oil change.
Source: EPA: Test Topics
Why the other answers are wrong
- Silicone oil — Silicone oil is not used as a refrigeration compressor lubricant.
- Polyolester oil — Polyolester oil is the usual partner for HFCs such as R-134a.
- Polyalkylene glycol oil — PAG oil is used mainly in automotive R-134a systems.
13. In a running system, what is in the liquid line between the condenser and the metering device?
- High-pressure liquidCorrect answer
- Low-pressure vapor
- High-pressure vapor
- Low-pressure liquid and vapor
Why “High-pressure liquid” is correct
After the condenser removes heat, the refrigerant is a high-pressure liquid, usually slightly subcooled. It flows through the liquid line to the metering device, where its pressure drops.
Source: EPA: Test Topics
Why the other answers are wrong
- Low-pressure vapor — Low-pressure vapor is in the suction line.
- High-pressure vapor — High-pressure vapor is in the discharge line before the condenser.
- Low-pressure liquid and vapor — A low-pressure mix is found after the metering device, in the evaporator.
14. When a single-component refrigerant is boiling in the evaporator at a steady pressure, what happens to its temperature?
- It rises steadily as it boils
- It stays about the same while liquid remainsCorrect answer
- It falls steadily as it boils
- It swings up and down with each compressor stroke
Why “It stays about the same while liquid remains” is correct
While a pure refrigerant changes from liquid to vapor at a fixed pressure, it stays at its saturation temperature; the heat it absorbs goes into boiling, not into raising temperature. Only after all liquid has boiled does the vapor begin to warm (superheat).
Source: EPA: Test Topics
Why the other answers are wrong
- It rises steadily as it boils — Temperature rises only after all the liquid has boiled off.
- It falls steadily as it boils — At constant pressure the boiling temperature does not fall.
- It swings up and down with each compressor stroke — Saturation temperature follows pressure, not compressor strokes.
15. Why do technicians use low-loss fittings on their hoses?
- To filter moisture out of the refrigerant as it flows
- To make hoses connect faster
- To cut refrigerant loss when hoses are disconnectedCorrect answer
- To raise the pressure rating of the hose
Why “To cut refrigerant loss when hoses are disconnected” is correct
40 CFR 82.152 defines a low-loss fitting as one that closes automatically or manually when disconnected, minimizing refrigerant released from hoses, appliances and recovery machines. It keeps the trapped hose charge from escaping.
Source: 40 CFR 82.152
Why the other answers are wrong
- To filter moisture out of the refrigerant as it flows — Fittings do not filter moisture; filter-driers do.
- To make hoses connect faster — Speed of connection is not the purpose.
- To raise the pressure rating of the hose — The fitting does not change the hose pressure rating.
16. A compressor burnout has left the R-22 in a system acidic and dirty. What must the technician do with it?
- Vent it, since it cannot be reused
- Mix it with clean R-22 to dilute it
- Leave it in the system
- Recover it into a recovery cylinderCorrect answer
Why “Recover it into a recovery cylinder” is correct
Recovery means removing refrigerant in any condition and storing it in an external container. Contaminated refrigerant must still be recovered; it can then be recycled for the same owner, sent for reclamation, or destroyed.
Source: 40 CFR 82.152; 40 CFR 82.154(a)
Why the other answers are wrong
- Vent it, since it cannot be reused — Contamination is not a reason to vent.
- Mix it with clean R-22 to dilute it — Diluting with clean refrigerant spreads the contamination.
- Leave it in the system — The system cannot be opened for repair with the refrigerant left in it.
17. In a recycling machine, what do the replaceable core filter-driers reduce?
- The amount of refrigerant in the cylinder
- Chlorine content of the refrigerant
- The refrigerant's ozone depletion potential
- Moisture, acidity and particlesCorrect answer
Why “Moisture, acidity and particles” is correct
40 CFR 82.152 notes that recycled refrigerant is generally cleaned by oil separation and passes through devices such as replaceable core filter-driers, which reduce moisture, acidity and particulate matter.
Source: 40 CFR 82.152
Why the other answers are wrong
- The amount of refrigerant in the cylinder — Filter-driers clean refrigerant; they are not meant to reduce the amount.
- Chlorine content of the refrigerant — Chlorine is part of the refrigerant molecule and is not filtered out.
- The refrigerant's ozone depletion potential — ODP is a property of the chemical and does not change.
18. Why should a new recovery cylinder be evacuated before its first use?
- To check that the cylinder is the correct color and type
- To remove air that would mix with the refrigerantCorrect answer
- To pre-cool the cylinder walls
- To meet the 80 percent fill limit
Why “To remove air that would mix with the refrigerant” is correct
A cylinder full of air would add non-condensables to the recovered refrigerant and raise cylinder pressure. Evacuating it first leaves a clean, empty container.
Source: EPA: Test Topics
Why the other answers are wrong
- To check that the cylinder is the correct color and type — Evacuation has nothing to do with cylinder color.
- To pre-cool the cylinder walls — Pulling a vacuum does not meaningfully cool the cylinder.
- To meet the 80 percent fill limit — The fill limit is met by weighing, not by evacuation.
19. Before recovering from an unfamiliar system, why should the technician confirm which refrigerant it holds?
- To pick the right cylinder and avoid mixingCorrect answer
- To decide whether the refrigerant may be vented
- To set the thermostat correctly
- To find the date the system was made
Why “To pick the right cylinder and avoid mixing” is correct
Each refrigerant should go into its own cylinder, so knowing the refrigerant first keeps it from being mixed with another. Check the nameplate and the system pressures before connecting.
Source: EPA: Test Topics
Why the other answers are wrong
- To decide whether the refrigerant may be vented — Non-exempt refrigerants may never be vented.
- To set the thermostat correctly — The thermostat setting has nothing to do with recovery.
- To find the date the system was made — The manufacture date is on the nameplate, but that is not the reason for identifying the refrigerant.
20. After evacuation the vacuum pump is valved off. The micron reading rises, then levels off and holds. What does this most likely mean?
- The vacuum is deep enough to charge
- The system has a large leak to the atmosphere
- Moisture is still boiling off inside the systemCorrect answer
- The micron gauge has failed
Why “Moisture is still boiling off inside the system” is correct
A reading that rises and then levels off usually means moisture or refrigerant is still turning to vapor inside a tight system. A reading that keeps rising without leveling off suggests a leak. More evacuation is needed before charging.
Source: EPA: Test Topics
Why the other answers are wrong
- The vacuum is deep enough to charge — A significant rise shows the system is not yet dry.
- The system has a large leak to the atmosphere — A leak to the atmosphere keeps the reading rising instead of leveling off.
- The micron gauge has failed — A gauge that responds this way is working.
21. Why must a refrigerant cylinder never be heated with a torch?
- The pressure can rise rapidly and rupture the cylinderCorrect answer
- The flame will turn the refrigerant into oxygen
- It voids the cylinder's color code
- It makes the refrigerant flammable
Why “The pressure can rise rapidly and rupture the cylinder” is correct
Heating a cylinder with an open flame can raise its pressure and weaken the metal, causing a rupture or explosion. Open flames can also break refrigerant down into toxic products.
Source: EPA: Test Topics
Why the other answers are wrong
- The flame will turn the refrigerant into oxygen — Heat does not turn refrigerant into oxygen.
- It voids the cylinder's color code — The danger is rupture, not the color code.
- It makes the refrigerant flammable — Heating does not make a nonflammable refrigerant flammable; the hazard is pressure.
22. How can a technician make sure a recovery cylinder stays under the 80 percent fill limit?
- Stop as soon as the recovery machine sounds strained
- Watch the cylinder pressure gauge
- Feel the side of the cylinder for cold spots
- Weigh it and compare with its allowed fill weightCorrect answer
Why “Weigh it and compare with its allowed fill weight” is correct
Pressure in a cylinder depends on temperature, not on how full it is, so a gauge cannot show the fill level. Weighing the cylinder, or using a float switch on cylinders that have one, shows how much liquid is inside.
Source: EPA: Test Topics
Why the other answers are wrong
- Stop as soon as the recovery machine sounds strained — Machine sound does not measure fill level.
- Watch the cylinder pressure gauge — Cylinder pressure follows temperature, not the amount of liquid.
- Feel the side of the cylinder for cold spots — Cold spots are an unreliable guess at the liquid level.
23. A technician will pressure-test a system with nitrogen. What limit should the test pressure respect?
- The full pressure available from the nitrogen cylinder
- The rated test pressure for that systemCorrect answer
- Whatever pressure the relief valve allows
- At least twice the system's normal operating pressure
Why “The rated test pressure for that system” is correct
The test pressure must not exceed what the system and its components are built for, as shown on the nameplate or in the manufacturer's instructions. A regulator sets that pressure, and a relief valve protects against regulator failure.
Source: EPA: Test Topics
Why the other answers are wrong
- The full pressure available from the nitrogen cylinder — Full cylinder pressure can be thousands of psig and would burst the system.
- Whatever pressure the relief valve allows — The relief valve is a backup, not the target pressure.
- At least twice the system's normal operating pressure — Doubling operating pressure can exceed the system rating.
24. A refrigerant leak has made the air in a small mechanical room stuffy and you feel dizzy. What should you do first?
- Light a torch to burn off the refrigerant
- Keep working quickly to finish the repair
- Leave the area and ventilate itCorrect answer
- Lie down on the floor until it passes
Why “Leave the area and ventilate it” is correct
Dizziness is a warning of oxygen deprivation or refrigerant overexposure. Get to fresh air, ventilate the space, and return only when it is safe or with proper breathing equipment.
Source: EPA: Test Topics
Why the other answers are wrong
- Light a torch to burn off the refrigerant — An open flame can break refrigerant down into toxic gases.
- Keep working quickly to finish the repair — Staying in the space can lead to unconsciousness or heart effects.
- Lie down on the floor until it passes — Refrigerant vapor collects low, so lying on the floor is the worst place to be.
25. What does the DOT classification tag on a refrigerant cylinder tell carriers and handlers?
- The technician who filled the cylinder
- The date the refrigerant was made
- The hazard class of the contentsCorrect answer
- The price per pound
Why “The hazard class of the contents” is correct
The Department of Transportation classification tag shows the hazard class of the cylinder's contents, such as nonflammable gas, so carriers handle it correctly. It goes alongside a label identifying the refrigerant itself.
Source: EPA: Test Topics
Why the other answers are wrong
- The technician who filled the cylinder — The tag does not identify who filled the cylinder.
- The date the refrigerant was made — Manufacture date is not what the DOT tag shows.
- The price per pound — Pricing is not part of hazard labeling.
Type III
26. A technician must bring an R-113 machine up to atmospheric pressure for a non-major repair. Which procedure follows 40 CFR 82.156(a)(1)(ii)?
- Use nitrogen alone, since R-113 is exempt from the heat requirement
- Use heat only, because nitrogen is never allowed on low-pressure machines
- Use compressed air to reach atmospheric, then purge before opening
- Heat it as far as heat will go, then add nitrogen up to atmosphericCorrect answer
Why “Heat it as far as heat will go, then add nitrogen up to atmospheric” is correct
For low-pressure refrigerants that boil above 85 °F at atmospheric pressure, such as R-113, the rule requires heat to raise internal pressure as much as possible. Nitrogen may then be used only to bring the pressure from that point up to atmospheric.
Source: 40 CFR 82.156(a)(1)(ii)
Why the other answers are wrong
- Use nitrogen alone, since R-113 is exempt from the heat requirement — Heat must be used first, as much as possible, before any nitrogen is added.
- Use heat only, because nitrogen is never allowed on low-pressure machines — Nitrogen is allowed on R-113 machines to make up the last of the pressure after heat.
- Use compressed air to reach atmospheric, then purge before opening — Air is not an allowed method and would contaminate the refrigerant.
27. An R-123 chiller is pulled down to 25 mm Hg absolute, then the pressure creeps up after the recovery unit is valved off. What should the technician do next?
- Open the chiller, since the shell is still well under a vacuum anyway
- Resume recovery until the pressure holds at the required levelCorrect answer
- Break the vacuum with nitrogen and start the repair
- Log the reading and leave the chiller as it is
Why “Resume recovery until the pressure holds at the required level” is correct
A pressure rise after recovery stops means liquid refrigerant is still present in the chiller or its oil. The technician should restart recovery and repeat the wait-and-watch check until the pressure stays at 25 mm Hg absolute.
Source: EPA: Test Topics; 40 CFR 82.156(a)
Why the other answers are wrong
- Open the chiller, since the shell is still well under a vacuum anyway — The chiller has not held the required level, so it is not ready to open.
- Break the vacuum with nitrogen and start the repair — The rising pressure shows refrigerant is still in the chiller, so breaking the vacuum now would be premature.
- Log the reading and leave the chiller as it is — Logging the rise does not recover the refrigerant still in the chiller.
28. A technician's micron gauge is used to confirm the evacuation of an R-11 chiller. Roughly what reading equals the 25 mm Hg absolute level in Table 1?
- 500 microns
- 25,000 micronsCorrect answer
- 2,500 microns
- 250,000 microns
Why “25,000 microns” is correct
A micron is one-thousandth of a millimetre of mercury, measured from a perfect vacuum. 25 mm Hg absolute is therefore 25,000 microns, the level a low-pressure appliance must reach before it is opened or disposed of.
Source: 40 CFR 82.156(a), Table 1; EPA: Test Topics
Why the other answers are wrong
- 500 microns — 500 microns is a common dehydration target and is far deeper than the Table 1 recovery level.
- 2,500 microns — This is off by a factor of ten; 1 mm Hg equals 1,000 microns.
- 250,000 microns — This is off by a factor of ten in the other direction.
29. A technician pulls the vapor space of an R-123 chiller to 25 mm Hg absolute, but liquid is still pooled in the bottom of the evaporator. Has the evacuation requirement been met?
- No; the refrigerant must be evacuated, including all the liquidCorrect answer
- Yes; the rule measures the vapor pressure only, not the liquid level
- Yes, if the liquid amount is under 200 pounds
- Only if the recovery unit was made after 1993
Why “No; the refrigerant must be evacuated, including all the liquid” is correct
40 CFR 82.156(a) requires technicians to evacuate the refrigerant, including all the liquid refrigerant, to the Table 1 level. A momentary reading over pooled liquid will not hold, because the liquid keeps boiling off and raising the pressure.
Source: 40 CFR 82.156(a)
Why the other answers are wrong
- Yes; the rule measures the vapor pressure only, not the liquid level — The rule names liquid refrigerant specifically; pooled liquid must be removed.
- Yes, if the liquid amount is under 200 pounds — There is no allowance for leaving liquid behind, whatever the amount.
- Only if the recovery unit was made after 1993 — The equipment date does not change the requirement to remove the liquid.
30. An R-11 chiller has a leaking evaporator that cannot reach Table 1 levels. Under the leaky-appliance rule, what is the first thing the technician should do?
- Evacuate the whole chiller to 0 psig and open it
- Isolate leaking components from non-leaking ones where possibleCorrect answer
- Pressurize the whole chiller with nitrogen to locate the leak first
- Vent the remaining vapor because it is contaminated
Why “Isolate leaking components from non-leaking ones where possible” is correct
40 CFR 82.156(a)(2) starts by asking the technician to isolate leaking from non-leaking components wherever possible. The non-leaking parts then go to the Table 1 level and the leaking parts to the lowest level attainable without substantial contamination, never above 0 psig.
Source: 40 CFR 82.156(a)(2)
Why the other answers are wrong
- Evacuate the whole chiller to 0 psig and open it — Non-leaking parts must still reach Table 1 levels, so the whole chiller cannot simply be taken to 0 psig.
- Pressurize the whole chiller with nitrogen to locate the leak first — The rule's first step is isolating leaking components, and adding nitrogen would contaminate the refrigerant still to be recovered.
- Vent the remaining vapor because it is contaminated — Venting refrigerant is prohibited; contaminated refrigerant is still recovered.
31. Hot water in the tubes has raised an idle R-11 chiller only to atmospheric pressure, which is not enough for a leak test. What is the accepted next step?
- Add nitrogen until the pressure reaches about 25 psig for a stronger test
- Add nitrogen through a regulator, staying at or under 10 psigCorrect answer
- Add compressed air through the purge connection
- Run the compressor to build pressure in the shell
Why “Add nitrogen through a regulator, staying at or under 10 psig” is correct
EPA lists nitrogen as the second choice for pressurizing a low-pressure system for leak testing, after heating. When nitrogen is used, it goes in through a pressure regulator and the test pressure is kept at or below 10 psig, or the manufacturer's lower limit (Trane specifies 8 psig), to protect the rupture disc.
Source: EPA: Test Topics; Trane CTV-SVX05H-EN, R-123 handling guide (8 psig leak test)
Why the other answers are wrong
- Add nitrogen until the pressure reaches about 25 psig for a stronger test — 25 psig is far above the safe limit and risks the rupture disc.
- Add compressed air through the purge connection — Compressed air is not an acceptable leak test gas.
- Run the compressor to build pressure in the shell — The compressor does not raise standing pressure in the shell for a leak test.
32. A 650-pound R-11 chiller that cools a chemical process exceeds the 30% leak rate. How often must leak inspections be done?
- Once per calendar year, until a full year of calculations is under the rate
- Once a month, until the chiller is retrofitted
- Every six months, until two inspections find no leaks
- Every three months, until four quarters in a row are under the rateCorrect answer
Why “Every three months, until four quarters in a row are under the rate” is correct
Industrial process refrigeration and commercial refrigeration appliances with 500 pounds or more must have a leak inspection once every three months after exceeding their leak rate. Inspections continue until leak rate calculations show four quarters in a row under the rate.
Source: 40 CFR 82.157(g)
Why the other answers are wrong
- Once per calendar year, until a full year of calculations is under the rate — Annual inspections apply to smaller IPR and commercial systems and to comfort cooling.
- Once a month, until the chiller is retrofitted — The rule does not set a monthly schedule.
- Every six months, until two inspections find no leaks — Semiannual inspections are not part of 40 CFR 82.157(g).
33. An automatic leak detection system that senses R-123 in the equipment-room air is used in place of leak inspections. At what concentration must it alert the owner?
- 10 parts per million
- 50 parts per million
- 1,000 parts per million
- 100 parts per millionCorrect answer
Why “100 parts per million” is correct
A system that detects refrigerant in air must accurately sense 10 ppm of the refrigerant and alert the owner when the concentration reaches 100 ppm. Its sensors must sit close to the compressor, evaporator, condenser and other likely leak points inside an enclosed building.
Source: 40 CFR 82.157(g)
Why the other answers are wrong
- 10 parts per million — 10 ppm is the level the system must be able to detect accurately, not the alert level.
- 50 parts per million — 50 ppm is not a figure in the rule.
- 1,000 parts per million — 1,000 ppm is ten times higher than the required alert level.
34. After a required leak inspection on an R-123 chiller, what must the technician's documentation to the owner include?
- The lot number and AHRI 700 test result of any reclaimed refrigerant used
- A signature from an EPA regional official
- The technician's certification test score
- A certification that all visible and accessible parts were inspectedCorrect answer
Why “A certification that all visible and accessible parts were inspected” is correct
Leak inspection records must show the date, the method used, the location of each leak found, and a certification that all visible and accessible parts of the appliance were inspected. The technician provides this to the owner, who keeps it.
Source: 40 CFR 82.157(l)
Why the other answers are wrong
- The lot number and AHRI 700 test result of any reclaimed refrigerant used — Reclaim lot numbers are not part of the leak inspection record.
- A signature from an EPA regional official — EPA does not sign leak inspection records.
- The technician's certification test score — Test scores are not part of the inspection record.
35. A 500-pound R-11 chiller serves an industrial process. Roughly how much refrigerant would it have to lose over 12 months to exceed its leak rate?
- More than 50 pounds
- More than 100 pounds
- More than 150 poundsCorrect answer
- More than 625 pounds
Why “More than 150 pounds” is correct
Industrial process refrigeration has a 30 percent leak rate, and the leak rate is the share of full charge that would be lost over 12 months. Thirty percent of 500 pounds is 150 pounds.
Source: 40 CFR 82.157(c); EPA: Leak Repair Requirements
Why the other answers are wrong
- More than 50 pounds — 50 pounds would be the 10 percent comfort cooling threshold for this charge.
- More than 100 pounds — 100 pounds would be the 20 percent commercial refrigeration threshold.
- More than 625 pounds — 625 pounds is 125 percent, the chronic leaker reporting level.
36. A replacement part for a leaking R-123 comfort chiller is not available within 30 days. If the owner meets the extension conditions, what is the longest the repair can be delayed?
- 60 days after delivery, with no overall limit
- Until the next cooling season begins
- 30 days after delivery, but not over 180 days totalCorrect answer
- 30 days after delivery, but not over 270 days total
Why “30 days after delivery, but not over 180 days total” is correct
When parts are not available, 40 CFR 82.157(f) allows up to 30 days after delivery of the needed components, not to exceed 180 days from when the appliance exceeded its leak rate. The cap is 270 days only when an industrial process shutdown is needed, and the owner must request the extension from EPA.
Source: 40 CFR 82.157(f)
Why the other answers are wrong
- 60 days after delivery, with no overall limit — The extension is 30 days after delivery and is capped.
- Until the next cooling season begins — The rule ties the extension to part delivery, not to the season.
- 30 days after delivery, but not over 270 days total — 270 days is the cap only when an industrial process shutdown is required.
37. An owner wrote a retrofit plan for a leaking R-11 chiller but then got the leaks under control. To ask EPA for relief from retrofitting, by when must the owner show the chiller no longer exceeds its leak rate?
- Within 30 days of the plan's date
- Within 180 days of the plan's dateCorrect answer
- Within one year of the plan's date
- Within 10 days of the plan's date
Why “Within 180 days of the plan's date” is correct
40 CFR 82.157(h)(5)(ii) lets an owner ask to be relieved of a retrofit or retirement plan if, within 180 days of the plan's date, it can show the appliance no longer exceeds its leak rate. The owner must also agree in writing to repair all identified leaks within one year of the plan date.
Source: 40 CFR 82.157(h); EPA: Leak Repair Requirements
Why the other answers are wrong
- Within 30 days of the plan's date — 30 days is when the plan must be written, not the relief window.
- Within one year of the plan's date — One year is the deadline for finishing the plan's work.
- Within 10 days of the plan's date — 10 days is the follow-up verification test window.
38. How long must the owner of a 300-pound R-123 chiller keep its service and leak inspection records?
- At least three yearsCorrect answer
- At least one year
- At least five years
- Until the next chiller overhaul
Why “At least three years” is correct
40 CFR 82.157(l) requires that leak repair records be kept for at least three years, in paper or electronic form, unless another period is stated. 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
- At least one year — One year is too short; the rule says three years.
- At least five years — Five years is longer than the general Part 82 requirement.
- Until the next chiller overhaul — Retention is set in years, not by service events.
39. Why does removing liquid at the start of recovery from an R-11 chiller save time?
- Liquid recovery needs no certified equipment
- Liquid recovery skips the 25 mm Hg requirement
- Liquid moves far more refrigerant per minute than vaporCorrect answer
- Liquid leaves the oil behind, along with all the refrigerant dissolved in it
Why “Liquid moves far more refrigerant per minute than vapor” is correct
A pound of liquid takes up far less volume than a pound of vapor, so pulling the liquid first moves most of the charge quickly. Vapor recovery then handles what is left.
Source: EPA: Test Topics
Why the other answers are wrong
- Liquid recovery needs no certified equipment — Certified equipment is required whether liquid or vapor is recovered.
- Liquid recovery skips the 25 mm Hg requirement — The chiller must still reach 25 mm Hg absolute.
- Liquid leaves the oil behind, along with all the refrigerant dissolved in it — Leaving refrigerant in the oil does not save time; it has to be recovered too.
40. The chilled-water pump on an R-123 chiller cannot run while the refrigerant is being recovered. How can the technician protect the tubes from freezing?
- Add antifreeze to the refrigerant
- Speed up recovery to finish faster
- Drain the water from the tubesCorrect answer
- Close the water valves and leave the water in place
Why “Drain the water from the tubes” is correct
EPA's test topics list two ways to prevent freezing during evacuation: circulate the water or remove it. If the water cannot be circulated, draining the tubes removes the risk.
Source: EPA: Test Topics
Why the other answers are wrong
- Add antifreeze to the refrigerant — Nothing should be added to the refrigerant; the water side is what needs attention.
- Speed up recovery to finish faster — Faster recovery cools the refrigerant faster and makes freezing more likely.
- Close the water valves and leave the water in place — Stagnant water in the tubes is exactly what freezes.
41. Which order of steps is correct when recovering refrigerant from an R-11 chiller before a major repair?
- Recover liquid, then vapor, then wait to see if pressure risesCorrect answer
- Recover vapor, then liquid, then open the chiller
- Recover liquid only, then open the chiller once it reaches 0 psig
- Recover vapor, add nitrogen, then recover liquid
Why “Recover liquid, then vapor, then wait to see if pressure rises” is correct
Removing the liquid first gets most of the charge out fastest. Vapor recovery then pulls the chiller to 25 mm Hg absolute, and a few minutes' wait shows whether liquid is still boiling off before the chiller is opened.
Source: EPA: Test Topics; 40 CFR 82.156(a)
Why the other answers are wrong
- Recover vapor, then liquid, then open the chiller — Liquid should come first, and the pressure must be checked before opening.
- Recover liquid only, then open the chiller once it reaches 0 psig — A major repair needs 25 mm Hg absolute, which takes vapor recovery as well.
- Recover vapor, add nitrogen, then recover liquid — Nitrogen is not part of recovery, and liquid should come out before vapor.
42. A technician is charging vapor into an evacuated R-11 chiller. At what point is it safe to switch to charging liquid?
- When the pressure is above the saturation pressure for 32 °FCorrect answer
- When the shell pressure reaches 0 psig
- After exactly 10 pounds of vapor have gone in
- As soon as the purge unit starts running
Why “When the pressure is above the saturation pressure for 32 °F” is correct
Liquid will not boil below freezing once the chiller pressure is above the saturation pressure that matches 32 °F. Until then, vapor is charged; after that, liquid can be added without freezing the water in the tubes.
Source: EPA: Test Topics
Why the other answers are wrong
- When the shell pressure reaches 0 psig — Liquid can be safely added well before atmospheric pressure, once the 32 °F point is passed.
- After exactly 10 pounds of vapor have gone in — The switch point depends on pressure, not a fixed weight.
- As soon as the purge unit starts running — Purge operation does not tell you when liquid charging is safe.
43. Which plan is correct for charging 600 pounds of R-123 into an evacuated centrifugal chiller?
- Charge vapor, then liquid, through the evaporator charging valve with water flowingCorrect answer
- Charge liquid, then vapor, through the condenser relief connection with the pumps off
- Charge liquid only, through the purge unit, with water drained
- Charge vapor only, through the compressor discharge, with pumps off
Why “Charge vapor, then liquid, through the evaporator charging valve with water flowing” is correct
EPA's test topics combine two charging points for centrifugals: introduce vapor before liquid to keep tube water from freezing, and charge through the evaporator charging valve. Keeping water circulating adds another layer of protection.
Source: EPA: Test Topics
Why the other answers are wrong
- Charge liquid, then vapor, through the condenser relief connection with the pumps off — Liquid first risks freezing, and still water in the tubes makes it worse.
- Charge liquid only, through the purge unit, with water drained — The purge unit is not a charging point, and liquid first risks freezing.
- Charge vapor only, through the compressor discharge, with pumps off — Centrifugals are charged through the evaporator charging valve, not the discharge.
44. Low-pressure refrigerants such as R-123 are most often used in which type of equipment?
- Household refrigerators
- Residential split heat pumps
- Supermarket display cases
- Large centrifugal chillersCorrect answer
Why “Large centrifugal chillers” is correct
Low-pressure refrigerants have low vapor density and suit centrifugal compressors that move very large volumes of vapor. That is why the Type III exam centers on centrifugal chillers.
Source: EPA: Test Topics; 40 CFR 82.152
Why the other answers are wrong
- Household refrigerators — Household refrigerators are small appliances, covered by Type I.
- Residential split heat pumps — Residential splits use higher-pressure refrigerants such as R-410A.
- Supermarket display cases — Display cases use medium- or high-pressure refrigerants.
45. On an idle R-11 chiller, the refrigerant and water are both at 72 °F, but the gauge reads well above the pressure-temperature chart value for 72 °F. What is the likely cause?
- A refrigerant undercharge
- Too much oil in the sump
- Chilled water flowing too fast
- Air or other noncondensables in the chillerCorrect answer
Why “Air or other noncondensables in the chiller” is correct
With liquid and vapor present at a steady temperature, the pressure should match the P-T chart for that refrigerant. Extra pressure above that value comes from gases that do not condense, which the purge unit should remove.
Source: EPA: Test Topics
Why the other answers are wrong
- A refrigerant undercharge — An undercharge does not raise standing pressure above the saturation value.
- Too much oil in the sump — Oil level does not push pressure above the P-T value.
- Chilled water flowing too fast — The chiller is idle, and water flow does not raise pressure above saturation.
46. A closed R-123 chiller holds both liquid and vapor. If the refrigerant warms from 70 °F to 90 °F, what happens to its pressure?
- It goes from below to above atmospheric pressureCorrect answer
- It stays the same, since the chiller is closed
- It falls further into a vacuum
- It jumps to about 100 psig
Why “It goes from below to above atmospheric pressure” is correct
R-123 boils at about 82 °F at atmospheric pressure. Below that temperature its saturation pressure is a vacuum; above it, slightly positive. The same rule is why warming the refrigerant can bring a chiller above atmosphere for leak testing.
Source: EPA: Test Topics; Hudson Technologies R-123 and R-11 P-T charts
Why the other answers are wrong
- It stays the same, since the chiller is closed — Saturated refrigerant pressure follows temperature even in a closed vessel.
- It falls further into a vacuum — Warming raises saturation pressure; it does not lower it.
- It jumps to about 100 psig — R-123 at 90 °F is only slightly above atmospheric pressure.
47. Under ASHRAE Standard 34, which safety group is R-123 assigned to?
- A1
- A2L
- B1Correct answer
- B2L
Why “B1” is correct
R-123 is classed B1: "B" for higher toxicity and "1" for no flame propagation. Its higher toxicity is why EPA's test topics single out a refrigerant sensor for R-123 equipment rooms; current editions of ASHRAE Standard 15 require one for every refrigerant.
Source: ASHRAE Standard 34; Hudson Technologies R-123 P-T chart (ASHRAE 34 rating); EPA: Test Topics
Why the other answers are wrong
- A1 — A1 is the lower-toxicity, non-flammable group of refrigerants such as R-11 and R-134a.
- A2L — A2L is for lower-toxicity, mildly flammable refrigerants.
- B2L — B2L is for higher-toxicity, mildly flammable refrigerants such as ammonia.
48. The R-123 alarm is sounding in an equipment room after a major leak. What protection is needed to go in?
- A paper dust mask
- Safety glasses and gloves only
- A self-contained breathing apparatusCorrect answer
- A cartridge respirator for paint fumes
Why “A self-contained breathing apparatus” is correct
A large leak can leave the room short of oxygen and full of refrigerant vapor. In that extreme case only self-contained breathing apparatus supplies safe air; otherwise people should stay out until the room is ventilated.
Source: EPA: Test Topics; ASHRAE 15-2016 Addendum c, Appendix E
Why the other answers are wrong
- A paper dust mask — Dust masks do not protect against refrigerant vapor or low oxygen.
- Safety glasses and gloves only — Glasses and gloves do not protect breathing.
- A cartridge respirator for paint fumes — Cartridge respirators do not supply oxygen in a displaced atmosphere.
49. What is the job of the rupture disc on a low-pressure chiller?
- Remove noncondensables from the condenser
- Relieve excess pressure before the shell can burstCorrect answer
- Let refrigerant out during normal operation
- Act as the charging point for liquid
Why “Relieve excess pressure before the shell can burst” is correct
ASHRAE Standard 15 requires pressure relief on refrigerant vessels. On a low-pressure chiller this is usually a rupture disc, which bursts if pressure gets too high, protecting the shell but releasing refrigerant. That is why leak test pressures stay well below its setting.
Source: ASHRAE Standard 15; EPA: Test Topics
Why the other answers are wrong
- Remove noncondensables from the condenser — Removing noncondensables is the purge unit's job.
- Let refrigerant out during normal operation — A rupture disc only opens on dangerous overpressure.
- Act as the charging point for liquid — The evaporator charging valve is the charging point.
50. Under ASHRAE Standard 15, what should an equipment-room refrigerant detector do when it senses refrigerant above its set point?
- Sound an alarm and start mechanical ventilationCorrect answer
- Shut off all power to the building
- Open the chiller rupture disc
- Start the purge unit to remove the leak
Why “Sound an alarm and start mechanical ventilation” is correct
ASHRAE Standard 15 ties the equipment-room detector to visual and audible alarms and to mechanical ventilation, with a set point no higher than the refrigerant's occupational exposure limit. People are warned to leave, and fresh air is brought in to clear the leaked refrigerant.
Source: ASHRAE 15-2016 Addendum c (detector set point at OEL); EPA: Test Topics
Why the other answers are wrong
- Shut off all power to the building — The detector does not cut building power.
- Open the chiller rupture disc — Opening the disc would release the whole charge.
- Start the purge unit to remove the leak — The purge removes noncondensables from inside the chiller, not refrigerant from the room.
More EPA 608 practice
Read next
- EPA 608 Study Guide: Core, Type I, Type II and Type III: EPA does not publish a study guide for the Section 608 exam. It publishes a list of test topics. This guide works through that list section by section, explains what each topic is about, and gives the numbers from the regulation you need to know.
- How to Get EPA 608 Certified: EPA Section 608 certification is the federal credential you need to work on the refrigerant circuit of stationary air-conditioning and refrigeration equipment. Here is who needs it, how the tests work, how to pick a certification type, where and how to test, including online, and what happens after you pass.
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.