EPA Section 608 Certification — Questions and Answers

Question 1: What causes a halide torch to change flame color when detecting chlorine-containing refrigerant leaks?

Oxygen depletion near the leak source
UV radiation from the refrigerant gas
Increased gas pressure near the detector nozzle
Combustion of chlorine compounds producing copper chloride (Correct answer)

Correct answer: Combustion of chlorine compounds producing copper chloride

A halide torch (also called a propane torch leak detector) draws air over a copper element. When chlorine-containing refrigerant is present, it reacts with the heated copper to form copper chloride, which changes the flame from blue to green or blue-green. This method only works with CFCs and HCFCs, not HFCs.

Question 2: When water leaks into a low-pressure chiller's refrigerant, the technician should be concerned about:

Reduced oil viscosity only
Lower operating pressure
Formation of acids and corrosion (Correct answer)
Improved efficiency

Correct answer: Formation of acids and corrosion

Moisture combines with refrigerant to form corrosive acids that damage the system.

Question 3: When using a system-dependent recovery system on a compressor-operated appliance, the technician should:

Install access fitting on both high and low-pressure sides of the system
Run the compressor and recover from the low side of the system only
Run the compressor and recover from the high side of the system only. (Correct answer)
Never allow the refrigerant to go to the high side of the system

Correct answer: Run the compressor and recover from the high side of the system only.

When using a system-dependent recovery system on a compressor-operated appliance, the most effective method is to run the appliance's compressor and recover refrigerant from the high side. This allows the compressor to push the refrigerant into the recovery cylinder, maximizing the amount recovered and ensuring efficient removal from the system.

Question 4: A recovery cylinder should never be filled beyond what percentage of its capacity?

90%
80% (Correct answer)
100%
60%

Correct answer: 80%

Recovery cylinders must not be filled beyond 80% of capacity to allow room for liquid expansion and prevent rupture.

Question 5: What gas is most commonly used to pressurize a system for leak testing without introducing refrigerant?

Oxygen
Carbon dioxide
Compressed air
Dry nitrogen (Correct answer)

Correct answer: Dry nitrogen

Dry nitrogen is used to pressure-test systems because it is inert and moisture-free.

Question 6: For a Type III low-pressure system with a charge of more than 200 lbs, what recovery efficiency is required using equipment made after November 15, 1993?

System must reach 29 inches of mercury vacuum
90% of charge must be recovered
System must reach 25 inches of mercury vacuum
System must reach 25 mmHg absolute (25 Torr) (Correct answer)

Correct answer: System must reach 25 mmHg absolute (25 Torr)

For low-pressure systems with charges over 200 lbs, the EPA requires recovery equipment to achieve 25 millimeters of mercury absolute pressure (25 mmHg or approximately 25 Torr absolute). Since low-pressure systems already operate in a vacuum, the recovery standard is expressed in absolute pressure rather than vacuum depth. This extremely low absolute pressure ensures maximum refrigerant recovery.

Question 7: A standing pressure test checks for leaks by doing what?

Adding dye
Pressurizing the system and watching for a pressure drop over time (Correct answer)
Listening with a microphone
Measuring temperature drop

Correct answer: Pressurizing the system and watching for a pressure drop over time

A standing test pressurizes the system and monitors whether pressure holds over time.

Question 8: Which of the following is a key requirement for refrigerant recovery and/or recycling equipment used for servicing MVAC systems under Section 609?

The equipment must be replaced every five years.
The equipment must be capable of handling at least ten different types of refrigerants.
The equipment must be painted yellow for safety identification.
The equipment must be certified by an EPA-approved organization like UL or Intertek. (Correct answer)

Correct answer: The equipment must be certified by an EPA-approved organization like UL or Intertek.

Section 609 requires that refrigerant handling equipment be certified by an EPA-approved independent standards testing organization, such as Underwriters Laboratories (UL) or Intertek, to ensure it meets specific SAE standards for refrigerant recovery and/or recycling.

Question 9: How does a technician become Section 609 certified?

Holding a driver's license
Buying recovery equipment
Passing an EPA-approved Section 609 exam (Correct answer)
Automatic upon hire

Correct answer: Passing an EPA-approved Section 609 exam

Certification requires passing an EPA-approved Section 609 test.

Question 10: When evacuating a system before recharging, what is the purpose of performing a "triple evacuation" (also called "triple deep evacuation")?

To satisfy EPA requirements for systems over 200 lbs before recharging
To verify the vacuum pump is functioning at rated capacity
To remove moisture more thoroughly by breaking vacuum with dry nitrogen between evacuation cycles (Correct answer)
To achieve three times the required vacuum depth for better system performance

Correct answer: To remove moisture more thoroughly by breaking vacuum with dry nitrogen between evacuation cycles

Triple evacuation (or triple deep evacuation) involves evacuating the system, breaking the vacuum with dry nitrogen, and evacuating again — repeated three times. This process is more effective at removing moisture than a single deep evacuation because nitrogen purging carries moisture to the vacuum pump. Each evacuation cycle removes a greater percentage of remaining moisture, protecting the system from acid formation.

Question 11: A refrigerant identifier is used primarily to detect:

The purity and type of refrigerant in a system (Correct answer)
System leaks
Oil level
Electrical faults

Correct answer: The purity and type of refrigerant in a system

A refrigerant identifier analyzes a sample to determine the type and purity of refrigerant present.

Question 12: A technician with only Type II certification may legally service what?

Low-pressure chillers
High-pressure appliances only (Correct answer)
Any appliance
Small appliances and high-pressure systems

Correct answer: High-pressure appliances only

Type II alone authorizes work on high- and very-high-pressure appliances only.

Question 13: A service shop begins working on MVAC systems for the first time. What one-time action must the shop owner take regarding their refrigerant handling equipment?

Register each piece of equipment with the equipment manufacturer.
Certify to their EPA Regional Office that they have acquired and are properly using approved equipment. (Correct answer)
Publish an announcement in a local newspaper about their new A/C service.
Submit training certificates for all technicians to the local government.

Correct answer: Certify to their EPA Regional Office that they have acquired and are properly using approved equipment.

New service shops or shops servicing MVAC systems for the first time are required to certify to their respective EPA Regional Office that they have obtained and are properly using approved refrigerant recovery/recycling equipment. This is a one-time requirement per shop.

Question 14: Which type of leak detector is considered the most sensitive and can detect refrigerant concentrations in the parts-per-billion range?

Ultrasonic acoustic detector
Infrared (IR) sensor detector (Correct answer)
Halide torch
Heated diode detector

Correct answer: Infrared (IR) sensor detector

Infrared (IR) sensor detectors are among the most sensitive refrigerant detection instruments, capable of detecting concentrations in the parts-per-billion range. They work by measuring the absorption of infrared light by refrigerant molecules, providing precise and reliable detection across multiple refrigerant types.

Question 15: Which type of chemical bond in CFC and HCFC molecules is primarily responsible for stratospheric ozone destruction?

Oxygen-fluorine bonds
Carbon-hydrogen bonds
Carbon-carbon double bonds
Chlorine atoms released by UV radiation (Correct answer)

Correct answer: Chlorine atoms released by UV radiation

UV light frees chlorine atoms, which catalytically destroy ozone molecules in the stratosphere.

Question 16: Which EPA 608 certification type covers hermetically sealed systems containing 5 pounds or less of CFC or HCFC refrigerant?

Type III
Type I (Correct answer)
Universal
Type II

Correct answer: Type I

Type I certification under EPA Section 608 covers small appliances — hermetically sealed systems manufactured, charged, and tested at the factory, containing 5 pounds or less of CFC or HCFC refrigerant. Examples include household refrigerators, window air conditioners, and dehumidifiers. Type I technicians use different recovery techniques appropriate for these sealed systems.

Question 17: What is the required recovery efficiency standard for a system containing more than 200 pounds of high-pressure refrigerant, when using recovery equipment manufactured after November 15, 1993?

95% efficiency
90% efficiency
System pressure must reach 15 inches of mercury vacuum (Correct answer)
80% efficiency

Correct answer: System pressure must reach 15 inches of mercury vacuum

For systems containing more than 200 pounds of refrigerant (Type II and Type III systems with charges over 200 lbs) using equipment manufactured after November 15, 1993, the EPA requires recovery to continue until the system reaches 15 inches of mercury vacuum. This stringent standard ensures maximum refrigerant capture from large commercial systems.

Question 18: When adding refrigerant as a liquid to a high-pressure system, where should it generally be introduced?

Through the leak detector port
Into the high side (liquid line) with compressor off (Correct answer)
Into the suction line while running
Into the compressor oil sump

Correct answer: Into the high side (liquid line) with compressor off

Liquid charging is done into the high side with the compressor off to avoid slugging the compressor.

Question 19: What does GWP stand for in the context of MVAC refrigerants?

Global Warming Potential (Correct answer)
General Warranty Provision
Gas Working Pressure
Ground Water Protection

Correct answer: Global Warming Potential

GWP measures how much a refrigerant contributes to global warming relative to CO2.

Question 20: Why should oxygen never be used to pressurize a refrigeration system for leak testing?

It leaks too fast to detect
It corrodes copper
It can cause a violent explosion when mixed with oil (Correct answer)
It is too expensive

Correct answer: It can cause a violent explosion when mixed with oil

Oxygen combined with compressor oil under pressure can cause a violent explosion.

Question 21: Which of the following best describes 'recycling' refrigerant in the MVAC context?

Cleaning refrigerant on-site to SAE standards for reuse in vehicles (Correct answer)
Diluting it with nitrogen
Sending it to a federal lab
Burning it for disposal

Correct answer: Cleaning refrigerant on-site to SAE standards for reuse in vehicles

Recycling means cleaning refrigerant on-site to SAE purity standards so it can be reused.

Question 22: Which of the following do the filter driers remove?

Mold Only
Moisture Only
Particulates Only
Moisture and Particulates (Correct answer)

Correct answer: Moisture and Particulates

Filter driers are essential components in a refrigeration system designed to remove both moisture and solid particulates. Moisture can lead to acid formation, corrosion, and freeze-ups, while particulates can clog expansion devices and damage compressors. By removing these contaminants, filter driers protect the system and extend its lifespan.

Question 23: Why is it important to never mix different refrigerants in the same recovery cylinder?

Mixed refrigerants cannot be reused and must be vented to atmosphere
Mixed refrigerants can cause cylinder over-pressurization leading to explosion
Different refrigerants react chemically to produce toxic byproducts in cylinders
Mixed refrigerants create a non-reclaimable contaminated blend that must be destroyed (Correct answer)

Correct answer: Mixed refrigerants create a non-reclaimable contaminated blend that must be destroyed

When different refrigerants are mixed in a recovery cylinder, the result is a contaminated blend that cannot be separated by standard recycling methods. The only option is to send the contaminated cylinder to a reclaimer who must destroy it, as the mixed refrigerant cannot be restored to a usable pure or certified blend. This wastes refrigerant and incurs disposal costs. Always use separate, clearly labeled cylinders for each refrigerant type.

Question 24: What is the purpose of a liquid line filter-drier in a high-pressure refrigeration system?

To remove moisture, acid, and particulates from the refrigerant (Correct answer)
To reduce refrigerant velocity entering the expansion device
To separate oil from refrigerant on the high-pressure side
To prevent refrigerant from flowing backward through the compressor

Correct answer: To remove moisture, acid, and particulates from the refrigerant

The liquid line filter-drier serves two critical functions: it contains a desiccant (typically molecular sieve or silica gel) to absorb moisture from the refrigerant, and it contains a filter element to trap particulates such as metal shavings and system debris. Moisture forms acid with refrigerant oils, causing corrosion and compressor failure, so drier maintenance is essential.

Question 25: Under the phaseout schedule, the production and import of HCFC-22 (R-22) for servicing existing equipment was banned beginning what year?

2015
2030
2020 (Correct answer)
2010

Correct answer: 2020

As of January 1, 2020, no new production or import of R-22 is allowed; only reclaimed/recovered stock may be used.

Question 26: To hold Universal certification, a technician must pass which exam sections?

Type II and III only
Core plus Type I, II, and III (Correct answer)
Type I and II only
Core only

Correct answer: Core plus Type I, II, and III

Universal certification requires passing the Core section plus all three type-specific sections.

Question 27: Equipment for recovery must be:

Certified by an EPA-approved testing laboratory. (Correct answer)
Used on all equipment manufactured after July 1, 1995.
CSA approved.
Used on all equipment manufactured after November 15, 1995.

Correct answer: Certified by an EPA-approved testing laboratory.

EPA regulations under Section 608 mandate that all refrigerant recovery and recycling equipment must be certified by an EPA-approved testing laboratory. This certification ensures that the equipment meets specific performance standards for efficiency and effectiveness in recovering refrigerants, thereby minimizing their release into the atmosphere during servicing.

Question 28: Under EPA Section 609, which entity is responsible for ensuring that technicians who purchase refrigerant in containers larger than 2 pounds are properly certified?

The local HVAC licensing board
The technician's employer or shop owner
The vehicle manufacturer
The refrigerant wholesaler or retailer selling the refrigerant (Correct answer)

Correct answer: The refrigerant wholesaler or retailer selling the refrigerant

EPA regulations require refrigerant wholesalers and retailers to sell containers larger than 2 pounds only to certified technicians. The seller bears responsibility for verifying certification before completing the sale, making point-of-sale verification a key enforcement mechanism.

Question 29: Which symptom most strongly suggests a low refrigerant charge in a high-pressure system?

Low suction pressure with high superheat (Correct answer)
Flooded evaporator
High suction pressure
Low superheat

Correct answer: Low suction pressure with high superheat

An undercharge causes low suction pressure and elevated superheat.

Question 30: When the leak rate exceeds ________ the charge per year, EPA regulations require that leaking commercial or industrial process refrigeration equipment be repaired.

5%
15%
25%
30% (Correct answer)

Correct answer: 30%

EPA regulations under Section 608 of the Clean Air Act set specific leak rate thresholds for different types of refrigeration equipment. For commercial and industrial process refrigeration, if the annual leak rate exceeds 30% of the full charge, the equipment must be repaired. This regulation aims to minimize refrigerant emissions and protect the ozone layer and climate.

Question 31: What type of oil must be used in vacuum pumps designed for HVAC/R refrigerant work?

Standard mineral oil
Dedicated vacuum pump oil (Correct answer)
Synthetic compressor oil
SAE 30 motor oil

Correct answer: Dedicated vacuum pump oil

Vacuum pump oil is specially formulated to maintain low vapor pressure and absorb moisture without breaking down, which standard lubricants cannot do.

Question 32: Which device measures the depth of vacuum achieved during evacuation of a high-pressure system?

Ammeter
Compound gauge only
Thermistor
Micron gauge (Correct answer)

Correct answer: Micron gauge

A micron gauge accurately measures deep vacuum levels during evacuation.

Question 33: Heat pumps that use R-134a should be checked with ________ for leaks.

HCFCs
pressurized nitrogen (Correct answer)
CFCs
compress dry air

Correct answer: pressurized nitrogen

When checking for leaks in a refrigeration system, especially one containing R-134a, it's crucial to use an inert gas like pressurized nitrogen. Nitrogen is non-condensable, non-flammable, and does not react with refrigerants or oils, making it safe and effective for pressure testing. Using other refrigerants would release harmful substances, and compressed dry air contains moisture which can damage the system.

Question 34: Recovered refrigerant may be returned to the same system or a system owned by the same owner without reclamation when it is only:

Reclaimed
Destroyed
Recycled or recovered (Correct answer)
Reprocessed by a manufacturer

Correct answer: Recycled or recovered

Refrigerant that is recovered or recycled may be returned to the same or another system owned by the same person without being reclaimed.

Question 35: On a Type II split system, what does an excessively long refrigerant line set do to system performance?

It only affects performance when outdoor ambient temperature is above 95°F
It increases suction pressure, improving efficiency
It has no effect if the pipes are properly insulated
It increases pressure drop and can reduce system capacity and efficiency (Correct answer)

Correct answer: It increases pressure drop and can reduce system capacity and efficiency

Long refrigerant line sets increase pressure drop in both suction and liquid lines. Suction line pressure drop causes the compressor to operate at a lower suction pressure, reducing capacity and efficiency. Excessive liquid line pressure drop can cause flash gas before the expansion device, further reducing system performance. Line set sizing must account for length and refrigerant type.

Question 36: A technician is called to service a commercial refrigeration unit containing 60 pounds of R-404A. The annualized leak rate has been calculated to be 25%. According to EPA regulations, what is the required action?

The system must be immediately shut down and replaced.
The owner has 12 months to monitor the leak before taking action.
The leak must be repaired within 30 days. (Correct answer)
No action is required as the leak rate is below the threshold for commercial refrigeration.

Correct answer: The leak must be repaired within 30 days.

For commercial refrigeration appliances containing more than 50 pounds of refrigerant, the EPA has set a maximum allowable annual leak rate of 20%. Since the calculated leak rate of 25% exceeds this threshold, the owner or operator is required to have the leak repaired within 30 days of discovery.

Question 37: Which of the following processes requires refrigerant to be reprocessed to meet AHRI Standard 700 specifications before it can be resold?

Reclaiming (Correct answer)
Retrofitting
Recovery
Recycling

Correct answer: Reclaiming

Reclaiming is the process of reprocessing a refrigerant to new product specifications, which are verified by chemical analysis. According to EPA regulations, reclaimed refrigerant must meet the purity levels specified in AHRI Standard 700 before it can be sold to a new owner.

Question 38: What document or record should a shop keep regarding refrigerant purchases and certified technicians?

A list of customer credit cards
Nothing is required to be kept
Proof of technician certification and refrigerant sales records (Correct answer)
Only the vehicle owner's phone number

Correct answer: Proof of technician certification and refrigerant sales records

Shops should retain technician certification proof and refrigerant transaction records.

Question 39: Which practice helps minimize refrigerant emissions during normal service work?

Using long hoses left open
Removing the Schrader cores permanently
Venting before disconnecting
Using low-loss fittings and short hoses (Correct answer)

Correct answer: Using low-loss fittings and short hoses

Low-loss fittings and short hoses reduce the amount of refrigerant trapped and released during service.

Question 40: In very high pressure appliances, what type of refrigerant is used?

R-50
R-500
R-503 (Correct answer)
R-410A

Correct answer: R-503

R-503 is an azeotropic refrigerant blend specifically designed for very low-temperature refrigeration applications, which inherently operate under very high pressures. Its properties make it suitable for specialized systems requiring extremely cold temperatures. The other refrigerants listed are typically used in different pressure ranges.

Question 41: Certification under Section 608 to service or dispose of regulated refrigeration and air conditioning equipment is:

Required to be renewed annually
Valid for the life of the technician (does not expire) (Correct answer)
Valid for five years and must be renewed
Only valid in the state where the test was taken

Correct answer: Valid for the life of the technician (does not expire)

Section 608 technician certification does not expire and is valid for life nationwide.

Question 42: When charging a Type II system with the zeotropic blend R-410A from a cylinder, why must the refrigerant be charged in the liquid phase rather than as a vapor?

Vapor charging causes fractionation, altering the blend's composition as it enters the system (Correct answer)
Vapor from R-410A cylinders is at too low a pressure to enter the system
Liquid refrigerant is warmer and reduces the risk of freeze-up during charging
Liquid charging is faster and reduces the risk of overcharging the system

Correct answer: Vapor charging causes fractionation, altering the blend's composition as it enters the system

R-410A is a zeotropic blend of R-32 and R-125, which have different boiling points. If charged as vapor, the more volatile component vaporizes preferentially, causing fractionation — the refrigerant entering the system no longer matches the specified blend ratio. Charging as a liquid ensures the exact mixture proportion enters the system as formulated.

Question 43: How many EPA Section 608 certification types are there?

Three
Five
Four (Correct answer)
Two

Correct answer: Four

Section 608 offers Type I, Type II, Type III, and Universal certifications.

Question 44: An electronic leak detector can detect leaks at what rate per year?

.5 oz
.20 oz
.25 oz (Correct answer)
1 oz

Correct answer: .25 oz

Under EPA regulations, owners or operators of refrigeration equipment are required to repair substantial leaks within a specific timeframe to mitigate refrigerant emissions. For most types of equipment, a substantial leak must be repaired within 30 days of its discovery. This regulation aims to quickly address significant refrigerant losses and protect the environment.

Question 45: If recovery equipment fails to pull the required vacuum, what is a likely cause?

Too much refrigerant in the cylinder line
A leak in the recovery setup or hoses (Correct answer)
Correct operation
Excess superheat

Correct answer: A leak in the recovery setup or hoses

Leaks in hoses or fittings prevent the recovery setup from reaching the required vacuum.

Question 46: How must a blended (zeotropic) refrigerant be added to a system during charging?

Either vapor or liquid — no difference
As vapor only through the suction line
As a 50/50 vapor-liquid mix
As liquid only (Correct answer)

Correct answer: As liquid only

Zeotropic blends like R-410A and R-404A must be charged as liquid to prevent fractionation, which would alter the blend's composition and performance.

Question 47: Which part of a system is a common location for refrigerant leaks?

Flare fittings, valve stems, and brazed joints (Correct answer)
Solid copper tubing midspan
The electrical disconnect
The insulation jacket

Correct answer: Flare fittings, valve stems, and brazed joints

Mechanical connections like flare fittings, valve stems, and joints are common leak points.

Question 48: In what year did the Montreal Protocol take place?

1989 (Correct answer)
2009
2001
1995

Correct answer: 1989

The Montreal Protocol on Substances that Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production and consumption of ozone-depleting substances. It was signed in 1987 and officially came into force on January 1, 1989, marking a significant global effort in environmental protection.

Question 49: Which refrigerant has been commonly used in older small appliances such as refrigerators manufactured before the mid-1990s, making proper recovery especially important due to its ozone depletion potential?

R-410A
R-32
R-12 (Correct answer)
R-134a

Correct answer: R-12

R-12 (CFC-12) was the standard refrigerant in older household refrigerators and small appliances before the phase-out under the Montreal Protocol. It has significant ozone depletion potential (ODP of 1.0), which is why proper recovery is critical.

Question 50: In a Type II refrigeration system, what is superheat and why is it important?

The temperature of the discharge gas above ambient; it indicates condenser efficiency
The difference between supply and return air temperatures across the coil
The number of degrees the refrigerant must be cooled in the condenser
The temperature rise of suction gas above its saturation temperature; it ensures only vapor enters the compressor (Correct answer)

Correct answer: The temperature rise of suction gas above its saturation temperature; it ensures only vapor enters the compressor

Superheat is the temperature of the suction gas above its saturation (boiling) point at a given pressure. Proper superheat ensures that all refrigerant has fully evaporated before entering the compressor, preventing liquid refrigerant from reaching the compressor (liquid slugging). Insufficient superheat risks compressor damage; excessive superheat reduces system efficiency.

Question 51: Which substance is an HFC refrigerant with zero ozone depletion potential?

R-22
R-134a (Correct answer)
R-12
R-11

Correct answer: R-134a

R-134a is a hydrofluorocarbon with no chlorine, giving it an ozone depletion potential of zero.

Question 52: The leak rate is based on a percentage of the total charge depending on the amount of refrigerant lost in the previous 12 months.

True
False (Correct answer)

Correct answer: False

This statement is false. The leak rate is calculated based on the amount of refrigerant added to an appliance over a 12-month period, not the amount lost. If the amount of refrigerant added exceeds a certain percentage of the appliance's full charge, it indicates a leak that must be repaired according to EPA regulations.

Question 53: Under EPA Section 608 regulations, which of the following refrigerant types has the highest Ozone Depletion Potential (ODP)?

HFOs (Hydrofluoroolefins)
HFCs (Hydrofluorocarbons)
CFCs (Chlorofluorocarbons) (Correct answer)
HCFCs (Hydrochlorofluorocarbons)

Correct answer: CFCs (Chlorofluorocarbons)

CFCs, containing chlorine, fluorine, and carbon, are the most damaging to the stratospheric ozone layer and therefore have the highest ODP. For reference, CFC-11 has an ODP of 1.0, while HCFCs like R-22 have a much lower ODP (e.g., 0.05), and HFCs and HFOs have an ODP of 0.

Question 54: A Type I certification allows a technician to service which kind of equipment?

High-pressure appliances
Small appliances with 5 pounds or less of refrigerant (Correct answer)
Low-pressure chillers
Motor vehicle air conditioners

Correct answer: Small appliances with 5 pounds or less of refrigerant

Type I certification covers small appliances containing 5 pounds or less of refrigerant.

Question 55: What is the Ozone Depletion Potential (ODP) of R-11?

0.5
0.8
1.0 (Correct answer)
1.5

Correct answer: 1.0

R-11 (CFC-11, trichlorofluoromethane) has an ODP of 1.0 and is used as the reference standard against which all other refrigerants are measured. An ODP of 1.0 means R-11 destroys as much ozone as the reference compound. Refrigerants with higher ODPs are more damaging; HFCs have an ODP of zero.

Question 56: When shipping a recovery cylinder of refrigerant, it must be labeled and transported in accordance with:

DOT hazardous materials regulations (Correct answer)
EPA Section 608 only
Local zoning codes
AHRI marketing rules

Correct answer: DOT hazardous materials regulations

Recovery cylinders are shipped under DOT hazardous materials regulations with proper labeling.

Question 57: Which international treaty was established to phase out the production of ozone-depleting substances like CFCs and HCFCs?

The Montreal Protocol (Correct answer)
The Paris Agreement
The Clean Air Act
The Kyoto Protocol

Correct answer: The Montreal Protocol

The Montreal Protocol on Substances that Deplete the Ozone Layer is the landmark international agreement designed to protect the stratospheric ozone layer by phasing out the production and consumption of ozone-depleting substances.

Question 58: Mixing two different refrigerants in one recovery cylinder results in:

Higher reclaim value
A reusable blend
No problem if pressures match
A cross-contaminated mixture that usually must be destroyed (Correct answer)

Correct answer: A cross-contaminated mixture that usually must be destroyed

Mixed refrigerants cannot be separated economically and typically must be sent for destruction, so cylinders should hold only one refrigerant type.

Question 59: What specialized safety equipment is required when working on R-11 or R-123 centrifugal chiller systems?

High-voltage rubber gloves due to electrostatic charge in low-pressure refrigerants
Chemical splash goggles and an activated carbon respirator only
Supplied air respirator or SCBA when entering confined spaces where concentrations may exceed exposure limits (Correct answer)
Full hazmat suit and Level A protection

Correct answer: Supplied air respirator or SCBA when entering confined spaces where concentrations may exceed exposure limits

R-11 and R-123 have higher toxicity ratings (ASHRAE Class B). When working in enclosed machine rooms or confined spaces where refrigerant concentrations could reach dangerous levels, technicians must use supplied-air respirators or self-contained breathing apparatus (SCBA). Half-face air-purifying respirators are not adequate for high-concentration emergency situations in confined chiller rooms.

Question 60: Synthetic oils based on ester can be combined with other oils.

B) True
A) False (Correct answer)

Correct answer: A) False

Synthetic oils based on esters, such as POE (polyol ester) oils, are generally not compatible with other types of oils, like mineral oils or alkylbenzene oils. Mixing different oil types can lead to chemical reactions, sludge formation, and degradation of lubrication properties, which can damage the refrigeration system. Therefore, it is crucial to use the correct and unmixed oil type specified for the refrigerant and system.

Question 61: What causes an intermittent cooling problem in an automotive A/C system that cools normally at first but gradually loses effectiveness as the car warms up?

TXV sensing bulb losing calibration above 80°F ambient
Low refrigerant charge that dissipates after initial cooldown
Condenser fan only operating correctly at low speeds
Expansion valve or orifice tube icing due to moisture in the system (Correct answer)

Correct answer: Expansion valve or orifice tube icing due to moisture in the system

Moisture in an MVAC system can cause intermittent cooling loss by freezing at the expansion device (orifice tube or TXV). Initially, the system cools normally. As refrigerant flow continues, moisture concentrates at the restriction point and freezes, blocking refrigerant flow and causing the evaporator to warm up. As the system sits, the ice melts and cooling resumes — a tell-tale sign of moisture contamination requiring drier replacement.

Question 62: What is the maximum temperature at which refrigerant cylinders should be stored?

85°F
150°F
100°F
125°F (Correct answer)

Correct answer: 125°F

Refrigerant cylinders must not be stored in areas exceeding 125°F (51.7°C) because heat increases internal pressure and risks rupture.

Question 63: What does the term 'azeotropic blend' mean when referring to refrigerants?

A blend approved only for commercial refrigeration
A blend that separates into components during a leak
A refrigerant that contains no lubricating oil
A mixture that behaves like a single refrigerant with a constant boiling point (Correct answer)

Correct answer: A mixture that behaves like a single refrigerant with a constant boiling point

An azeotropic blend maintains its composition during phase changes and boils at a constant temperature, behaving like a single-component refrigerant.

Question 64: Refrigerant recovered from a contaminated or burned-out compressor system should be:

Vented to atmosphere
Recovered into a separate cylinder and sent for reclamation or destruction (Correct answer)
Mixed with clean refrigerant to dilute it
Reused immediately in another system

Correct answer: Recovered into a separate cylinder and sent for reclamation or destruction

Heavily contaminated refrigerant must be kept separate and sent for reclamation or destruction, never reused as-is.

Question 65: What is the ASHRAE/ARI standard cylinder color for R-22 refrigerant?

Green (Correct answer)
Yellow
Rose (pink)
Light blue

Correct answer: Green

ASHRAE/ARI assigns green as the standard cylinder color for R-22 to prevent misidentification during service.

Question 66: What is subcooling in a high-pressure refrigeration system and how is it measured?

Temperature of suction gas below ambient; measured at the evaporator outlet
Temperature of liquid refrigerant below its saturation temperature at the measured pressure; measured at the liquid line (Correct answer)
Temperature of refrigerant in the receiver below the low-pressure cutout setpoint
Temperature drop across the condenser; measured between condenser inlet and outlet

Correct answer: Temperature of liquid refrigerant below its saturation temperature at the measured pressure; measured at the liquid line

Subcooling is the number of degrees a liquid refrigerant is cooled below its saturation temperature at a given pressure. It is measured at the liquid line by comparing actual refrigerant temperature to the saturation temperature at the measured liquid line pressure. Proper subcooling (typically 10-20°F) ensures liquid refrigerant arrives at the expansion device without flashing, improving system efficiency.

Question 67: A self-contained recovery device for high-pressure refrigerant uses its own what to remove refrigerant?

Nitrogen pressure
Its own compressor or pump (Correct answer)
Gravity only
The appliance's compressor

Correct answer: Its own compressor or pump

Self-contained recovery equipment has its own means (compressor/pump) to draw refrigerant without relying on the appliance.

Question 68: For which scenario does EPA Section 608 NOT require refrigerant recovery before opening a system?

Cleaning coil fins without opening the refrigerant circuit (Correct answer)
Replacing a leaking evaporator coil on a window air conditioner
Adding refrigerant to an undercharged room air conditioner
Replacing a failed compressor on a household refrigerator

Correct answer: Cleaning coil fins without opening the refrigerant circuit

Recovery is not required when the work being performed does not involve opening the refrigerant circuit. Cleaning coil fins is an external service task that does not expose refrigerant. However, any work that requires opening the refrigerant circuit — such as component replacement, brazing, or charging — requires refrigerant recovery before proceeding, regardless of the charge size.

Question 69: What exactly does a sling psychrometer measure?

Super heat
Latent heat
Wet and dry bulb temperature (Correct answer)
Barometric pressure

Correct answer: Wet and dry bulb temperature

A sling psychrometer is a device used to measure both the dry-bulb temperature (the ambient air temperature) and the wet-bulb temperature. The wet-bulb temperature is measured by a thermometer with its bulb wrapped in a wet cloth, which cools due to evaporation. These two readings are then used to determine relative humidity and dew point.

Question 70: Which component is most commonly associated with refrigerant leaks in a split-system air conditioner?

Condenser fan motor
Flare fittings and brazed joints (Correct answer)
Air filter housing
Thermostat wiring

Correct answer: Flare fittings and brazed joints

Flare fittings and brazed joints are the most common sources of refrigerant leaks in split-system air conditioners. These connection points can develop leaks due to vibration, improper installation technique, or material fatigue over time. Technicians should always inspect these areas first during a leak search.

Question 71: When performing a leak check after a system repair, which area should always be prioritized first?

The area where the repair was made (Correct answer)
The expansion valve body
The compressor electrical terminals
The evaporator coil fins

Correct answer: The area where the repair was made

After completing a repair, the technician should always start the leak verification test at the exact point of repair. This confirms the repair is sealed before checking other system areas. Verifying the repair point first ensures the primary source of leakage has been successfully addressed.

Question 72: If an MVAC system is contaminated with an unknown or mixed refrigerant, what is the proper action?

Vent it and recharge
Mix it with fresh R-134a
Recover it into a separate container for reclamation or disposal (Correct answer)
Return it directly to the same vehicle

Correct answer: Recover it into a separate container for reclamation or disposal

Contaminated refrigerant must be recovered separately and sent for reclamation or disposal.

Question 73: What is the impedance symbol?

P
I
R
Z (Correct answer)

Correct answer: Z

In electrical engineering, the symbol 'Z' is universally used to represent impedance. Impedance is the measure of the opposition that a circuit presents to a current when a voltage is applied, encompassing both resistance and reactance. It is a complex quantity, unlike simple resistance 'R'.

Question 74: After completing a leak repair on a system, what must a technician verify before returning the system to service?

Verify the repair by performing a follow-up leak test (Correct answer)
Replace the entire refrigerant charge with a new refrigerant
Submit a repair report to the EPA within 24 hours
Charge the system to full capacity immediately

Correct answer: Verify the repair by performing a follow-up leak test

After repairing a leak, the technician must perform a follow-up leak test to verify the repair was successful before returning the system to service. This confirms the repair sealed the leak and prevents continued refrigerant loss and environmental harm.

Question 75: Before switching to liquid charging on an R-410a system with a water-cooled condenser, you must first charge with vapor to a pressure of at least ________.

220 psig
320 psig
120 psig (Correct answer)
20 psig

Correct answer: 120 psig

When charging an R-410a system, it's essential to initially charge with vapor until the system pressure reaches at least 120 psig. This prevents the liquid refrigerant from slugging the compressor, which can cause severe damage. Once this pressure is achieved, liquid charging can safely commence, as the compressor is less likely to be damaged by liquid refrigerant at higher system pressures.

Question 76: The usage of certified recovery equipment is the first step in using proper recovery practices that is certified by:

EPA only
EPA approved laboratory (Correct answer)
Manufacturers approved by UL
EPA field supervisors

Correct answer: EPA approved laboratory

The EPA requires that recovery equipment used by technicians be certified by an EPA-approved laboratory. This certification ensures that the equipment meets specific standards for efficiency and safety in recovering refrigerants. Using certified equipment is a fundamental practice for complying with environmental regulations and preventing refrigerant emissions.

Question 77: Section 609 certification is specifically required for technicians who do what?

Manufacture refrigerant
Service or repair MVAC systems for consideration (Correct answer)
Repair commercial chillers
Install home AC units

Correct answer: Service or repair MVAC systems for consideration

Section 609 covers technicians who service MVAC systems for compensation.

Question 78: If a low-pressure system's rupture disc fails or releases, the technician should:

Ignore it if the system still cools
Recover refrigerant and replace the disc before recharging (Correct answer)
Add more refrigerant immediately
Tape over the opening

Correct answer: Recover refrigerant and replace the disc before recharging

A released disc means the charge is lost and the disc must be replaced before recharging.

Question 79: Excessive purging from a low-pressure system is a concern under the Clean Air Act because:

It uses too much electricity
It increases oil consumption
It can vent refrigerant along with non-condensables (Correct answer)
It cools the room

Correct answer: It can vent refrigerant along with non-condensables

Older purge units can release refrigerant with the purged air, which violates venting rules.

Question 80: How does a refrigerant's "vapor pressure" affect the type of recovery equipment needed?

Vapor pressure has no effect on recovery equipment selection
All refrigerants use identical recovery equipment regardless of vapor pressure
High vapor pressure (high-pressure) refrigerants require compressor-based recovery; very low-pressure refrigerants may use heat and temperature differential methods (Correct answer)
Higher vapor pressure refrigerants require vacuum pumps; lower vapor pressure refrigerants only need gravity recovery

Correct answer: High vapor pressure (high-pressure) refrigerants require compressor-based recovery; very low-pressure refrigerants may use heat and temperature differential methods

Refrigerant vapor pressure at operating temperatures determines the recovery approach. High-pressure refrigerants (R-22, R-410A) have significant vapor pressure at room temperature, requiring compressor-based recovery machines to capture them efficiently. Low-pressure refrigerants (R-11, R-123) have very low vapor pressures and can sometimes be recovered using heat applied to the evaporator to drive refrigerant toward the recovery cylinder. Equipment selection must match refrigerant characteristics.

Question 81: What color combination identifies a DOT-approved refrigerant recovery cylinder?

All green
All yellow
Gray body with yellow top (Correct answer)
Blue body with white top

Correct answer: Gray body with yellow top

Recovery cylinders are marked with a gray body and yellow top to distinguish them from disposable refrigerant cylinders.

Question 82: When inspecting for leaks in various systems, which gas should be used?

Oxygen
Carbon
Hydrogen
Nitrogen (Correct answer)

Correct answer: Nitrogen

Nitrogen is the preferred gas for pressure testing and leak detection in refrigeration systems. It is an inert, dry gas that is non-flammable, non-toxic, and will not react with refrigerants or system components. Using nitrogen helps prevent the introduction of moisture or contaminants, which can damage the system.

Question 83: A technician who disposes of a high-pressure appliance must do what before final disposal?

Vent the refrigerant slowly
Cut the lines immediately
Recover the refrigerant and verify required evacuation (Correct answer)
Add fresh refrigerant

Correct answer: Recover the refrigerant and verify required evacuation

Refrigerant must be recovered to the required level before an appliance is disposed of.

Question 84: A technician who only adds refrigerant to a customer's car AC without charge still needs which certification?

Section 609 if done for consideration (Correct answer)
No certification needed
A state plumbing license
Section 608 Type I

Correct answer: Section 609 if done for consideration

Section 609 certification is required when servicing MVAC for consideration.

Question 85: All refrigerated recovery cylinders are approved by this agency:

ARI
OSHA
DOT (Correct answer)
EPA

Correct answer: DOT

Open-drive compressors are characterized by having the compressor and its motor as separate units, connected by a shaft or belt, with the motor external to the sealed refrigerant circuit. Reciprocating compressors are a common type that can be found in open-drive configurations, particularly in larger industrial and commercial refrigeration applications. This design allows for easier motor maintenance or replacement compared to hermetic or semi-hermetic types.

Question 86: Which document proves a technician's Section 609 certification?

Vehicle registration
Sales receipt
Driver's license
EPA Section 609 certification card (Correct answer)

Correct answer: EPA Section 609 certification card

A Section 609 certification card documents the technician's qualification.

Question 87: Convert 5 tons of energy into BTUs every hour.

60,000 (Correct answer)
50,000
80,000
70,000

Correct answer: 60,000

Electronic leak detectors are highly sensitive instruments used to identify refrigerant leaks in HVAC/R systems. The EPA mandates that certified leak detectors must be capable of detecting leaks at a rate of 0.25 ounces per year (or 7 grams per year) for CFC, HCFC, and HFC refrigerants. This sensitivity ensures that even very small leaks, which can contribute significantly to environmental emissions over time, are promptly identified and addressed.

Question 88: Only a stable _________ allows you to accurately read refrigerant pressure.

Volume
All of the Above
Temperature (Correct answer)
Density

Correct answer: Temperature

Refrigerant pressure is directly dependent on its temperature in a closed system. For an accurate pressure reading, the refrigerant must be at a stable temperature, allowing it to reach thermal equilibrium. Fluctuations in temperature will cause corresponding fluctuations in pressure, making precise measurement and diagnosis impossible.

Question 89: Under Section 609, what must happen to refrigerant recovered from an MVAC system before it is reused in a different vehicle?

It must be sent to an EPA-certified reclaimation facility before reuse
It must be recycled using approved equipment that meets Section 609 standards (Correct answer)
It must be mixed with fresh refrigerant at a 50/50 ratio
It can be transferred directly from the recovery cylinder to another vehicle

Correct answer: It must be recycled using approved equipment that meets Section 609 standards

Under Section 609, refrigerant recovered from one MVAC system must be recycled using approved equipment that meets EPA Section 609 standards (which include oil separation and moisture removal) before being reused in a different vehicle. Direct transfer without recycling is not permitted because recovered refrigerant may be contaminated with oil, moisture, or air.

Question 90: Under EPA Section 608, an appliance with a full charge of 50 pounds or more of a regulated refrigerant is defined as "chronically leaking" and must be reported to the EPA if it leaks what percentage of its full charge in a calendar year?

100%
125% (Correct answer)
50%
75%

Correct answer: 125%

If an appliance with 50 or more pounds of a regulated refrigerant leaks 125% or more of its full charge in a calendar year, it is considered a chronically leaking appliance, and the owner or operator must submit a report to the EPA by March 1st of the following year.

Question 91: What is the function of the accumulator found in some MVAC systems instead of a receiver-drier?

It stores excess refrigerant on the low-pressure side and protects the compressor from liquid slugging (Correct answer)
It increases the pressure of suction gas entering the compressor
It replaces the expansion valve in low-pressure systems
It measures refrigerant charge level for the diagnostic port

Correct answer: It stores excess refrigerant on the low-pressure side and protects the compressor from liquid slugging

The accumulator is located on the low-pressure (suction) side between the evaporator and compressor. It stores any liquid refrigerant that might not have fully evaporated in the evaporator, preventing liquid from entering the compressor (which could cause catastrophic damage known as liquid slugging). Systems using accumulators typically use an orifice tube instead of a TXV for refrigerant metering.

Question 92: Which of the following refrigerants is only used in disposable cylinders:

None of the above
Either virgin or recovery refrigerant
Recovery refrigerant
Virgin refrigerant (Correct answer)

Correct answer: Virgin refrigerant

Virgin refrigerant, which is new and unused, is typically sold in disposable cylinders. These cylinders are designed for single use and are not intended for refilling with recovered or recycled refrigerants. This practice helps prevent contamination and ensures the purity of new refrigerant.

Question 93: Which trace gas may be used to pressurize a high-pressure system to find leaks without violating the venting prohibition?

Compressed air with oil
Pure oxygen
Nitrogen with a trace of refrigerant (Correct answer)
Pure refrigerant

Correct answer: Nitrogen with a trace of refrigerant

Nitrogen with a small trace of refrigerant is an accepted leak-testing method.

Question 94: What is the ASHRAE/ARI standard cylinder color for R-410A refrigerant?

Green
Rose (pink) (Correct answer)
Yellow
Orange

Correct answer: Rose (pink)

ASHRAE/ARI assigns rose (pink) as the standard cylinder color for R-410A to distinguish it from other refrigerants during service.

Question 95: If a technician fails one type but passes Core, what happens?

They lose all credit
They get Type I automatically
They keep credit for Core and retake only the failed type (Correct answer)
They must retake Core

Correct answer: They keep credit for Core and retake only the failed type

Core credit is retained, so only the failed type section must be retaken.

Question 96: Recordkeeping for leak repairs on a 50+ pound appliance must include which information?

Only the refrigerant type
Nothing if under warranty
The date, leak rate, and repair actions taken (Correct answer)
Only the technician's name

Correct answer: The date, leak rate, and repair actions taken

Records must document the date, calculated leak rate, and the repairs performed.

Question 97: What ASHRAE/ARI color code identifies R-404A refrigerant cylinders?

Green
Orange (Correct answer)
Rose (pink)
Light blue

Correct answer: Orange

ASHRAE/ARI assigns orange as the standard cylinder color for R-404A, the HFC blend widely used in commercial refrigeration as an R-502 replacement.

Question 98: A recovery cylinder should never be filled beyond what percentage of its capacity?

60%
70%
80% (Correct answer)
95%

Correct answer: 80%

Recovery cylinders must not be filled above 80% to allow room for liquid expansion and prevent rupture.

Question 99: The required recovery level for a low-pressure appliance with a full charge during disposal is:

15 psig
25 mm Hg absolute (Correct answer)
0 psig
10 inches of vacuum

Correct answer: 25 mm Hg absolute

Disposal of low-pressure appliances requires evacuation to 25 mm Hg absolute.

Question 100: A technician recovers refrigerant from a Type I small appliance and wants to reuse it in another similar system. What must be done with the recovered refrigerant before it can be legally recharged into a different owner's equipment?

It can be recharged directly without any processing
It must be recycled or reclaimed to ARI 700 purity standards (Correct answer)
It must be destroyed by an EPA-approved facility
It must be tested for moisture content only

Correct answer: It must be recycled or reclaimed to ARI 700 purity standards

Recovered refrigerant that will be used in a different owner's equipment must be reclaimed to ARI 700 standards by a certified reclaimer. Simply recycling on-site is only acceptable when recharging the same system or a system owned by the same owner.

EPA Section 608 Certification

The EPA Section 608 certification is required for technicians who maintain, service, repair, or dispose of equipment that could release refrigerants into the atmosphere.

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Sources & references

Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

epa.gov — Test delivery, eligibility, score validity · verified Oct 2026
ecfr.gov — Renewal, test delivery, exam format, passing score, retake policy, score release · verified Oct 2026