Free EPA 608 Type 3 practice test for low-pressure appliances (chillers, purge units, R-123). Each attempt draws a random 25 questions from the 50 below — instant scoring, explanations, no signup. Pass mark: 18 of 25 (72%).
Free EPA 608 Type 3 practice questions
1. Technicians servicing low-pressure appliances must hold Type III certification or Universal certification. (True or false)
Correct answer: True
The source says technicians maintaining, servicing, repairing, or disposing of low-pressure appliances must be certified as Type III Technicians or Universal Technicians.
2. High head pressure on a low-pressure system can indicate air in the system and possible purge-unit trouble. (True or false)
Correct answer: True
The source says high head pressure indicates air in a low-pressure system and that the purge unit may not be operating properly.
3. Excessive running of a purge system on a low-pressure chiller usually indicates a leaking system. (True or false)
Correct answer: True
The source states that excessive running of a purge system on a low-pressure chiller generally indicates a leaking system.
4. Before recovering refrigerant from a chiller suspected of tube leaks, the water sides of the evaporator and condenser should be drained. (True or false)
Correct answer: True
The source says to drain the water sides of the evaporator and condenser prior to recovering refrigerant from a chiller suspected of having tube leaks.
5. Open-drive low-pressure refrigeration systems are particularly susceptible to leaks from the shaft seal. (True or false)
Correct answer: True
The source states that low-pressure refrigeration systems with open-drive type compressors are particularly susceptible to leaks from the shaft seal.
6. Most low-pressure appliances are used for comfort cooling. (True or false)
Correct answer: True
The source says most low-pressure appliances are used for comfort cooling.
7. According to the source, which methods can make leak checking a charged low-pressure machine more efficient? (Select all that apply)
Correct answer: Circulated hot water, Heating blankets
Charged low-pressure refrigeration machines may be most efficiently leak checked by adding heat with circulated hot water or heating blankets.
8. During vapor or liquid removal from a low-pressure refrigeration system, which items should be on according to the source? (Select all that apply)
Correct answer: System water pumps, Recovery compressor, Recovery condenser water
The source states that the system's water pumps, recovery compressor, and recovery condenser water should all be on during vapor or liquid removal.
9. Which repairs are considered major repairs on low-pressure appliances according to the source? (Select all that apply)
Correct answer: Replacing a compressor, Replacing a condenser, Replacing an evaporator
The source identifies replacing or repairing a compressor, condenser, or evaporator as a major repair.
10. According to the source, why are room sensors and alarms required in machinery rooms? (Select all that apply)
Correct answer: Because of refrigerant characteristics, Because refrigerants are heavier than air and can displace oxygen
The source says sensors and alarms are required not only because of refrigerant characteristics, but also because refrigerants are heavier than air and can displace oxygen.
11. After the refrigerant leaves the purge unit, where does it go?
Correct answer: Evaporator
The refrigerant from the purge unit free from air and moisture enters the evaporator through the expansion valve.
12. Which classification best describes R-123's toxicity according to ASHRAE safety rating?
Correct answer: High toxicity
R-123 is identified as having high toxicity.
13. What is the ASHRAE safety rating of R-1233zd?
Correct answer: A1
The ASHRAE safety rating of R-1233zd is A1.
14. What is the boiling point of R-123?PT Chart
Correct answer: 82 ℉
The boiling point of R-123 is 82 ℉.
15. What is the pressure of R-123 at 80°F on the PT chart?PT Chart
Correct answer: 1.2 inches Hg
On the PT chart, the R-123 value at 80°F is 1.2 inches Hg vacuum.
16. While preparing to charge a low-pressure chiller, you check the safety limit for over-pressure protection. The rupture disc is designed toburst at:
Correct answer: 15 psig
For low-pressure refrigeration systems like chillers using R-123 or R-11, the EPA specifies that the rupture disc is set to relieve at 15 psig.This is a standard safety setting to prevent system overpressure while avoiding unnecessary releases during normal operation.
17. Which of the following components are only found in Type 3 appliances?
Correct answer: Purge Unit
The Purge Unit is the only component found exclusively in Type 3 appliances.
18. Which of the following is not a Type 3 refrigerant?
Correct answer: R-22
R-22 is a Type 2 high-pressure refrigerant.
19. Which of the following refrigerants would be used in a low-pressure appliance?
Correct answer: R-123
Among the options provided, R-123 is the refrigerant used in low-pressure appliances. It is specifically classified as a low-pressurerefrigerant.
20. You've pressurized a chiller tube with colored water using a tube test kit. Which result confirms the tube is leaking?
Correct answer: Dye seeping out and visible color marking
A hydrostatic tube test kit uses colored water under pressure; dye oozing and visible colored marks identify theleak path.
21. With the water side drained, why is the drain valve opening the preferred spot to sample with a leak detector?
Correct answer: It's the lowest port where leaked vapor gathers
Once drained, any leaked refrigerant can migrate to the lowest opening, so placing a leak detector probe in thedrain valve opening gives the best chance to detect it.
22. Continuous excessive moisture collection in which component of a low-pressure refrigeration system could indicate a leak?
Correct answer: Purge Unit
Excessive moisture collection in the purge unit could indicate that the condenser or the chiller barrel tubes are leaking and drawingwater into the system
23. After pulling a low-pressure chiller down to 1 mm Hg, the reading climbs to 2.7 mm Hg over a short hold. What is the compliant next stepaccording to ASHRAE?
Correct answer: Perform additional leak checking before any charging
ASHRAE Guidelines 3 states that if the pressure in the system rises from 1 mm Hg to a level above 2.5 mm Hgduring vacuum testing, the system should be further leak-checked.
24. When leak testing a low-pressure refrigeration system with nitrogen, exceeding ____ psig could cause the ____ to fail.
Correct answer: 10; Rupture disc
While leak testing a low-pressure chiller with nitrogen, the maximum pressure should not exceed 10 psig. If it exceeds 10 psig, therupture disc will burst open.
25. Where does water usually leak into low-pressure chillers?
Correct answer: Failed condenser gasket
Water most commonly leaks into low-pressure chillers through a failed condenser gasket because the inside is belowatmospheric pressure. Tube leaks or valve failure are less common causes.
26. A belt-driven non-hermetic compressor has sat idle for months and leaks on startup. What condition most likely explains the leakage?
Correct answer: Rubber in the rotating shaft seal hardened and lost sealing
If a belt-driven non-hermetic compressor has not been used for several months, the rubber seals in the rotatingshaft may harden and fail to seal the system properly.
27. A low-pressure chiller with a full charge >200 lb is found leaking on June 15, 2024. The owner chooses a replacement that uses a refrigerant that is exempt from venting prohibitions. By what date must the unit be retired or retrofitted?
Correct answer: December 15, 2025
When the replacement uses a refrigerant exempt from venting prohibitions (e.g., R-717 or R-744), the retirement or retrofit window extends to 18 months from the leak-detection date. Counting 18 months from June 15, 2024 lands on December 15, 2025.
28. How long must owners and operators of low-pressure chillers using R11 refrigerant keep records of leak inspections, initial verification, and follow-up verification tests?
Correct answer: 3 years
As per the EPA, it is compulsory to keep the records for any appliance containing 50 or more pounds refrigerant for a minimum of 3 years.
29. How long must owners and operators of regulated appliances normally containing 50 or more pounds of CFC refrigerant keep records of leak inspections, initial leak verification, and follow-up verification tests?
Correct answer: 3 years
Owners and operators of regulated appliances containing 50 or more pounds of regulated refrigerant should maintain all records for at least 3 years.
30. When disposing of an HVAC appliance with 10 pounds of refrigerant, what is one EPA-mandated recordkeeping requirement?
Correct answer: Keep disposal records for at least 3 years
Disposal records for appliances with 5-50 pounds refrigerant must be kept for at least 3 years.
31. Why do recovery units used on low-pressure chillers include a high-pressure cut-out set near the 10 psig range?
Correct answer: To prevent the rupture disc from bursting as pressure climbs
Low-pressure chillers have rupture discs that can open around 10-15 psig; the cut-out on recovery units prevents exceeding ~10 psig and protects the system.
32. You're beginning recovery on a low-pressure chiller at ambient conditions. To follow best practice, you should:
Correct answer: Pump out liquid first, then recover vapor
Refrigerant removal from a low-pressure system typically begins with the removal of liquid refrigerant and then finishes with the removal of vapor.
33. Why use a water-cooled recovery unit?
Correct answer: Faster recovery
Water-cooled units allow faster recovery.
34. In the case of confirmed leaks during refrigerant recovery in a chiller, what must be done?
Correct answer: Drain water from condenser and evaporator barrels
Water must be drained from the condenser and evaporator to prevent mixing impurities with refrigerant during recovery.
35. What is a requirement for equipment used for recovery, evacuation, and troubleshooting purposes, manufactured after November 15, 1993?
Correct answer: They must be fitted with low-loss fittings
Any equipment manufactured after November 15, 1993, for these purposes must be equipped with low-loss fittings to ensure efficient and environmentally friendly operation.
36. While evacuating a low-pressure chiller with no confirmed tube leaks, the water pump is accidentally switched off. As recovery continues, the barrel temperature keeps dropping. What is the immediate risk if you do not restore water circulation?
Correct answer: Ice formation that can damage tubes and pumps
With no leaks present, water must keep moving during evacuation to avoid freezing and equipment damage.
37. What risk is associated with attempting to melt ice formed in the chiller system after charging with liquid refrigerant?
Correct answer: Risk of rupture and bursting of coils
Charging liquid refrigerant under a high vacuum can cause ice formation in the system. Attempting to melt this ice may lead to coil damage and refrigerant leaks.
38. While charging a water-cooled, low-pressure chiller after evacuation, which indicator tells you it's safe to switch from vapor to liquid charging?
Correct answer: Saturation temperature increases above 32°F
Keep vapor-charging until system pressure corresponds to a saturation temperature around 32°F (≈0°C). That threshold puts you above the freezing risk before introducing liquid.
39. Identify the recovery requirements for equipment disposal
Correct answer: 25 mm of Hg absolute
The EPA requires systems to be evacuated to 25 mm Hg absolute (nearly a perfect vacuum) before equipment disposal. This standard ensures almost all refrigerant is recovered and prevents environmental harm.
40. Water present in the system can freeze if?
Correct answer: A large vacuum pump is used for evacuation
Water in the system can freeze if a large vacuum pump is used during evacuation, as the rapid decrease in pressure and temperature can lead to ice formation.
41. To introduce initial refrigerant vapor from the lowest point on a centrifugal chiller, which service connection should be used?
Correct answer: Evaporator charging valve
The evaporator charging valve is the lowest access point on all centrifugal chillers and air-conditioning appliances.
42. During the evacuation of a moisture-laden chiller, the vacuum stalls, and frost begins to form in the piping. What action should the technician take to restore flow without adding refrigerant?
Correct answer: Break the vacuum with a brief nitrogen sweep, then resume evacuation
Introducing nitrogen raises pressure and temperature, preventing freezing of the moisture inside the system. After the brief nitrogen sweep, resume evacuation to remove both the nitrogen and the moisture.
43. After confirming a leak, a technician is scheduled to replace an evaporator coil on a low-pressure chiller. Under EPA rules, this job isclassified as a:
Correct answer: Major repair
According to EPA regulations, a major repair involves the removal of specific components such as the condenser,evaporator, auxiliary heat exchanger coil, or compressor. Thus, replacing an evaporator coil falls under the major repair category.
44. A mechanical room contains equipment using A1, A2L, and B2 refrigerants. To comply with ASHRAE Standard 15-2013, the refrigerantalarm system must detect leaks from:
Correct answer: All refrigerant safety groups
ASHRAE Standard 15-2013 requires the use of room sensors and alarms to detect leaks of refrigerantbelonging to all safety groups. Detection isn't limited to one class.
45. According to ASHRAE Standard 15-2013, which equipment is mandated to detect refrigerant leaks?
Correct answer: Room Sensors
ASHRAE Standard 15-2013 requires equipment rooms to be equipped with electronic refrigerant detectors, also known as room sensors,to detect refrigerant leaks.
46. During a design review, a junior technician proposes installing two pressure relief valves in series on the discharge line “for extra safety.”The correct response is:
Correct answer: Not allowed; relief valves must never be installed in series
Pressure relief valves should never be installed in series to the system lines. It doesn't add protection and cancause improper discharge.
47. What is the main function of isopropyl alcohol in refrigeration systems?
Correct answer: To remove ice off the sight glass
The purpose of isopropyl alcohol is to remove ice from the sight glass.
48. If a unit experiences a compressor burnout, we would collect an ____ as part of a ____.
Correct answer: oil sample; major repair
When a compressor burnout occurs, it is considered a major repair according to EPA regulations. In such cases, taking an oil sample isessential to assess the condition of the refrigerant oil.
49. Why do low-pressure chillers require purge units?
Correct answer: Because they operate below atmospheric pressure
Low-pressure chillers require purge units because they operate below atmospheric pressure.
50. What is the primary purpose of a purge unit on a low-pressure chiller?
Correct answer: To remove non-condensables that leak into the system
The source states that the primary purpose of a purge unit is to remove non-condensables that leak into a low-pressure chiller system.
Your score
What the EPA 608 Type III certification covers
Type III (low-pressure) certification covers appliances that operate at or below atmospheric pressure. The dominant equipment is the large centrifugal chiller found in commercial buildings, hospitals, and universities. Active refrigerants are R-123; R-11 is fully phased out. Because these systems run under vacuum, leaks draw air and moisture in rather than pushing refrigerant out.
The Type III exam section has 25 questions and covers five core areas:
Low-pressure refrigerants and properties -- R-123 (boiling point 82 degrees F), R-11 (phased out), and newer HFO alternative R-1233zd.
Purge unit operation -- Continuous removal of non-condensable gases (air, nitrogen) that infiltrate through sub-atmospheric seals; excessive purge runtime signals a system leak.
Rupture disc and pressure limits -- Burst rating 15 psig; maximum nitrogen pressure test 10 psig; exceeding 10 psig risks catastrophic disc failure.
Recovery procedures -- Evacuate to 25 mm Hg absolute for disposal; remove liquid first then vapor; keep water circulating to prevent tube freezing during recovery.
Leak detection and repair -- Nitrogen leak test (never water); oil pre-heat to 130 degrees F minimum before startup; record retention 3 years for systems with 50 or more pounds of refrigerant.
Key numbers to memorize: Rupture disc burst = 15 psig. Maximum leak test pressure = 10 psig. Recovery vacuum for disposal = 25 mm Hg absolute. Oil pre-heat minimum = 130 degrees F. Record retention = 3 years.
Low-pressure system safety and equipment
Technicians working on low-pressure chillers must approach every procedure with the vacuum in mind. The exam tests these thresholds directly:
Parameter
Value
Why it matters on the exam
Rupture disc burst rating
15 psig
Disc protects system from over-pressure; know the value cold
Maximum nitrogen leak test pressure
10 psig
Exceeding 10 psig blows the rupture disc; tested directly
Oil pre-heat temperature
130 degrees F minimum
Required before startup to prevent bearing damage from slugging
Disposal recovery vacuum
25 mm Hg absolute
EPA mandate for equipment with low-pressure refrigerant; not inches Hg
Water-cooled centrifugal chillers circulate water through condenser and evaporator tubes. During refrigerant recovery, keep water flowing to prevent tube freezing as evaporator temperatures drop. If tube leaks are suspected, drain the water sides of both the evaporator and condenser before starting recovery to prevent water contamination of the refrigerant charge.
Recovery sequence: remove liquid refrigerant first, then pull out remaining vapor. Use a water-cooled recovery unit for fastest throughput. For disposal, evacuate to 25 mm Hg absolute (a near-perfect vacuum). After reaching the target vacuum, wait a few minutes -- if pressure rises above 2.5 mm Hg, perform additional leak checking before charging.
After this practice test, study the Type III study guide for a full topic breakdown, or take the Type I small appliance practice test, Type II high-pressure practice test, or the Universal practice test for full exam simulation. All practice tests are free with no login. Create a free account to unlock all 569 verified questions across every section plus weak-spot tracking. Pro ($14.99 lifetime) adds AI Tutor sessions, full progress history, and study path features.
Purge units and air infiltration in low-pressure systems
Purge units are found only on low-pressure chillers -- they are not used on high-pressure equipment. Because the system runs in a vacuum, air and moisture infiltrate through shaft seals, gaskets, and imperfect fittings. The purge unit separates refrigerant vapor from non-condensables, vents air to atmosphere, and routes refrigerant back to the evaporator. EPA regulations require technicians to log purge unit runtime and emissions. Excessive purge cycles confirm a system leak that must be located and repaired. High head pressure combined with heavy purge activity is a classic Type III exam scenario.
Moisture contamination and acid formation
Moisture is the primary cause of acid formation in centrifugal chiller systems. When water vapor combines with R-123 at operating temperatures it forms hydrochloric and hydrofluoric acid, damaging compressor bearings, motor windings, and expansion devices. Technicians monitor the oil acid number (neutralization number) and refrigerant moisture content regularly. When moisture exceeds specification, the corrective path is filter-drier replacement and refrigerant processing -- or off-site reclamation when contamination is severe. Refrigerant sampling to a certified lab is a tested distinction: knowing when reclamation is required versus when on-site drying is sufficient appears directly on the exam.
Frequently asked questions about the EPA 608 Type 3 exam
How many questions are on the EPA 608 Type 3 exam?
The Type III section has 25 questions. Every section of the EPA 608 exam (Core, Type I, Type II, and Type III) contains exactly 25 questions. If you pursue Universal certification you sit for all four sections on the same day, for a total of 100 questions.
What is the passing score for the EPA 608 Type 3 exam?
You must answer 72% of questions correctly to pass. On the 25-question Type III section that means getting 18 questions right (18 divided by 25 = 72%). The same 72% threshold applies to the Core, Type I, and Type II sections.
Is this EPA 608 Type 3 practice test free?
Yes. All 50 Type III practice questions with instant scoring, answers and explanations on this page are completely free with no account required. Create a free account to unlock all 569 verified questions across every section plus weak-spot tracking. Pro at $14.99 lifetime adds AI Tutor sessions, full progress history, and study path features.
What is Type III on the EPA 608 exam?
Type III covers low-pressure appliances -- equipment that operates at or below atmospheric pressure. The main equipment type is the large centrifugal chiller used for commercial comfort cooling. Refrigerants include R-123 (active) and R-11 (fully phased out). Because these systems run in a partial vacuum, leaks draw air and moisture in rather than releasing refrigerant out, which is the opposite of high-pressure systems.
What vacuum level is required for low-pressure appliance disposal?
25 mm Hg absolute. EPA regulations require evacuating low-pressure appliances to 25 mm Hg absolute before disposal. This is not the same as 25 inches Hg vacuum -- mm Hg absolute is a far deeper vacuum. After reaching the target, wait a few minutes: if pressure climbs above 2.5 mm Hg the system has a leak that must be addressed before charging.
What refrigerants do low-pressure systems use?
R-123 is the primary active refrigerant. R-11 has been fully phased out. R-1233zd is an HFO alternative with an A1 ASHRAE safety rating. All three operate below atmospheric pressure, which is what classifies a system as low-pressure under Section 608.
What is a purge unit on a centrifugal chiller?
A purge unit continuously removes non-condensable gases (mainly air) that infiltrate the chiller shell through sub-atmospheric seals. The purge unit separates air from refrigerant vapor, vents air to atmosphere, and routes clean refrigerant back to the evaporator. High purge runtime or excessive purge cycles indicate a system leak that must be investigated and repaired.
What is the rupture disc pressure rating on a low-pressure system?
15 psig. The rupture disc is a one-time safety device that bursts if system pressure reaches 15 psig, protecting the chiller from catastrophic over-pressure. During nitrogen leak testing, the maximum pressure is 10 psig -- this safety margin ensures the disc does not blow during testing.
How should you study for the EPA 608 Type 3 exam?
Memorize the five key numbers first: rupture disc burst pressure (15 psig), maximum leak test pressure (10 psig), oil pre-heat temperature (130 degrees F), disposal recovery vacuum (25 mm Hg absolute), and record retention (3 years). Then work through all 50 practice questions on this page, reviewing the explanation after each answer. Read the Type III study guide for a topic-by-topic breakdown. For weak-spot tracking across all four sections, create a free account to access all 569 verified questions.
