EPA Section 608 Certification — Questions and Answers

Question 1: Heating the refrigerant in a low-pressure appliance during recovery is used to:

Damage the compressor
Speed up recovery by raising vapor pressure (Correct answer)
Convert it to a high-pressure refrigerant
Reduce the charge weight

Correct answer: Speed up recovery by raising vapor pressure

Gently warming the refrigerant raises its pressure, allowing faster and more complete recovery.

Question 2: What happens to a high-pressure refrigerant system's discharge pressure when the condenser becomes fouled with dirt and debris?

Discharge pressure increases because heat rejection is impaired (Correct answer)
The system shuts down on a low-pressure safety switch
Suction pressure increases while discharge pressure remains constant
Discharge pressure decreases as airflow restriction reduces compressor load

Correct answer: Discharge pressure increases because heat rejection is impaired

When condenser coils are fouled, airflow is restricted and heat rejection is impaired. The refrigerant in the condenser cannot release heat efficiently, so the condensing temperature and pressure rise. High discharge pressure causes the compressor to work harder, increasing energy consumption, reducing system efficiency, and potentially tripping high-pressure cutout switches.

Question 3: What is the primary limitation of using soap bubbles for refrigerant leak detection?

Damages system components on contact
Only works with CFC refrigerants
Cannot be used on copper tubing
Ineffective for detecting small or slow leaks (Correct answer)

Correct answer: Ineffective for detecting small or slow leaks

Soap bubble solutions are only effective for detecting fairly significant leaks where enough refrigerant is escaping to visibly inflate a bubble. Small, slow, or intermittent leaks may not produce enough flow to create bubbles, making this method unsuitable for detecting minor refrigerant losses.

Question 4: A purge unit on a low-pressure chiller that runs excessively often indicates:

Overcharge of refrigerant
Excessive condenser water flow
A leak allowing air into the system (Correct answer)
Too little oil

Correct answer: A leak allowing air into the system

Frequent purging signals that air is continuously entering through a leak.

Question 5: In an enclosed space, a large refrigerant leak is dangerous primarily because the refrigerant can:

Turn into a flammable acid instantly
Lower the room temperature below freezing
Increase the oxygen concentration to unsafe levels
Displace oxygen and cause asphyxiation (Correct answer)

Correct answer: Displace oxygen and cause asphyxiation

Most refrigerants are heavier than air and can displace oxygen, leading to suffocation in confined spaces.

Question 6: The sale of CFC and HCFC refrigerants was restricted to certified technicians on which of the following dates?

November 14th , 1994 (Correct answer)
November 14th , 1997
November 14th , 1996
November 14th , 1995

Correct answer: November 14th , 1994

To control the release of ozone-depleting substances, the EPA mandated that as of November 14, 1994, the sale of CFC and HCFC refrigerants was restricted to technicians certified under Section 608 of the Clean Air Act. This measure was put in place to ensure that only trained professionals handled these refrigerants, reducing improper venting and environmental damage.

Question 7: Refrigerant containers used to store recovered MVAC refrigerant must be which color or marked for the specific refrigerant?

Any clean steel drum
DOT-approved containers labeled for the specific refrigerant (Correct answer)
Open-top buckets
Glass jars

Correct answer: DOT-approved containers labeled for the specific refrigerant

Recovered refrigerant must be stored in DOT-approved containers labeled for that refrigerant.

Question 8: Under EPA Section 608, the term 'small appliance' for Type I certification is defined as equipment that is fully manufactured, charged, and hermetically sealed with how much refrigerant?

10 pounds or less
5 pounds or less (Correct answer)
15 pounds or less
20 pounds or less

Correct answer: 5 pounds or less

EPA regulations define small appliances (Type I) as fully manufactured, charged, and hermetically sealed systems containing 5 pounds or less of refrigerant. This distinguishes them from larger systems covered under Type II and Type III certifications.

Question 9: Which statement is TRUE regarding the Section 608 venting prohibition for substitute refrigerants?

Only CFCs and HCFCs are subject to the venting prohibition; HFCs may be vented
HFCs used as refrigerant substitutes are also subject to the EPA's venting prohibition under Section 608 (Correct answer)
The venting prohibition only applies to refrigerants above 50 lbs per system
The venting prohibition does not apply to refrigerants with a GWP below 1,000

Correct answer: HFCs used as refrigerant substitutes are also subject to the EPA's venting prohibition under Section 608

The EPA extended the Section 608 venting prohibition to HFC refrigerants used as substitutes for ozone-depleting substances. This means R-410A, R-134a, R-404A, and other HFCs are all subject to the prohibition against intentional venting to the atmosphere. The prohibition applies to all refrigerants used in equipment covered by Section 608, regardless of ODP — it is now driven by both ozone protection and climate concerns.

Question 10: Under EPA Section 608, which of the following activities requires the technician to be certified?

Programming a thermostat on a split-system air conditioner
Opening a refrigerant circuit to replace a component (Correct answer)
Testing electrical connections on an A/C condenser unit
Installing new ductwork with no refrigerant exposure

Correct answer: Opening a refrigerant circuit to replace a component

EPA Section 608 certification is required for any technician who opens a refrigerant circuit — meaning any work that involves recovering, adding, or potentially releasing refrigerant. Installing ductwork, testing electrical components, and programming thermostats do not involve working with the refrigerant circuit and do not require EPA 608 certification.

Question 11: The disposable cylinders must be:

Discarded. (Correct answer)
Stored away.
Recovered and used again.
Used for air.

Correct answer: Discarded.

Disposable refrigerant cylinders are designed for single use only and must be discarded once empty. They are not built to withstand the pressures of repeated refilling and reuse, which could lead to dangerous ruptures or leaks. Proper disposal involves ensuring they are completely empty and then recycling them according to local regulations.

Question 12: A technician who only adds refrigerant to a customer's car AC without charge still needs which certification?

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

Correct answer: Section 609 if done for consideration

Section 609 certification is required when servicing MVAC for consideration.

Question 13: The ozone layer absorbs and scatters ________ from the sun.

ultraviolet light (Correct answer)
gamma radiation
infrared light
x-radiation

Correct answer: ultraviolet light

The ozone layer, located in the stratosphere, plays a vital role in protecting life on Earth by absorbing and scattering harmful ultraviolet (UV) light from the sun. Specifically, it blocks most of the sun's UVB radiation, which can cause skin cancer, cataracts, and harm to ecosystems. Without the ozone layer, life on Earth would be severely impacted by this intense radiation.

Question 14: Under EPA Section 608, which individuals are legally permitted to purchase refrigerant in containers larger than 2 pounds?

Any homeowner repairing their own equipment
Anyone holding a valid state mechanical license
EPA Section 608 certified technicians only (Correct answer)
Any licensed HVAC business owner

Correct answer: EPA Section 608 certified technicians only

EPA regulations restrict the sale of refrigerant in containers larger than 2 pounds to technicians who have been certified under Section 608. This rule helps prevent unqualified handling and illegal venting of refrigerants.

Question 15: Which ASHRAE refrigerant safety classification indicates the lowest toxicity AND non-flammability?

B1
A1 (Correct answer)
A3
B2

Correct answer: A1

Class A1 refrigerants have lower chronic toxicity (A) and do not propagate flame (1), making them the safest category — examples include R-134a and R-410A.

Question 16: A Type III chiller's purge unit is activating far more frequently than normal. What is the most likely cause?

Air is leaking into the system at an abnormal rate (Correct answer)
The compressor is operating at higher-than-rated speed
The refrigerant charge has been overfilled
The condenser water temperature is too cold

Correct answer: Air is leaking into the system at an abnormal rate

The purge unit removes non-condensable gases (primarily air) that infiltrate the system because it operates under vacuum. Abnormally frequent purge activation means more air than usual is entering the system, which is a strong indicator of a leak in the vacuum-side components such as shaft seals, flanges, or fittings. This is an important diagnostic signal unique to low-pressure equipment.

Question 17: Why do low-pressure chiller systems (Type III) operate under vacuum rather than under pressure?

To prevent refrigerant from venting if there is a leak
Because their refrigerants have boiling points above typical evaporator temperatures, so evaporator pressure is below atmospheric (Correct answer)
Because their refrigerants are too toxic to be stored under pressure
To improve compressor efficiency at large tonnage

Correct answer: Because their refrigerants have boiling points above typical evaporator temperatures, so evaporator pressure is below atmospheric

Low-pressure refrigerants like R-11 and R-123 have atmospheric boiling points well above typical evaporator temperatures. At evaporator temperatures (35-45°F), these refrigerants would be below their normal boiling point, creating pressures below 14.7 psia (below atmospheric). This means the system operates in a vacuum on the low side, so air and moisture can be drawn in through any leaks rather than refrigerant leaking out.

Question 18: Under what circumstances may a refrigerant recovery machine's recovery efficiency standards be waived?

When the technician is Universal-certified
When the system has a known leak that has already vented most of the refrigerant (Correct answer)
Recovery efficiency standards cannot be waived under any circumstances
When working on a system smaller than 1 pound charge

Correct answer: When the system has a known leak that has already vented most of the refrigerant

The EPA does provide relief from recovery requirements when a system's refrigerant has already been substantially lost due to a catastrophic failure or leak. If a technician can document that the system was nearly empty due to a leak before they arrived, the normal efficiency standards may not be achievable. Documentation is critical in such cases to demonstrate compliance intent.

Question 19: What is the primary environmental concern that led to phasing out R-12?

Flammability
Ozone depletion (Correct answer)
Toxicity
Cost

Correct answer: Ozone depletion

R-12 is a CFC with high ozone-depletion potential, prompting its phase-out.

Question 20: The phasedown of HFCs, which protects the climate rather than ozone, was added through which amendment to the Montreal Protocol?

Copenhagen Amendment
Kigali Amendment (Correct answer)
Beijing Amendment
London Amendment

Correct answer: Kigali Amendment

The Kigali Amendment added a global HFC phasedown to address climate impact.

Question 21: A Type II system has an evaporator saturation temperature of 20°F and a suction line temperature of 45°F. What is the suction line superheat?

20°F
25°F (Correct answer)
65°F
45°F

Correct answer: 25°F

Superheat equals the actual suction line temperature minus the saturation temperature at the suction pressure. 45°F (actual) − 20°F (saturation) = 25°F superheat. This value falls within a typical acceptable range for many commercial refrigeration systems. Technicians use this calculation to evaluate whether the expansion device is feeding the evaporator correctly.

Question 22: All comfort cooling systems containing more than 50 pounds of refrigerant must be repaired when the annual leak rate exceeds _____ .

20%
15% (Correct answer)
10%
5%

Correct answer: 15%

All comfort cooling systems containing more than 50 pounds of refrigerant must be repaired when the annual leak rate exceeds 15%. This EPA regulation aims to reduce refrigerant emissions from larger air conditioning and refrigeration units. Prompt repair of leaks helps protect the ozone layer and mitigate climate change.

Question 23: Under Section 609, small cans of refrigerant (2 pounds or less) for MVAC top-off use sold at retail stores may be purchased by:

Only licensed automotive repair shops
The general public without certification requirements (Correct answer)
Only EPA Section 609 certified technicians
Any person over age 18 with a state ID

Correct answer: The general public without certification requirements

EPA Section 609 regulations allow small containers of 2 pounds or less of MVAC refrigerant to be sold to the general public without requiring certification. These small "top-off" cans are available at auto parts stores for consumer use. The certification requirement applies to technicians purchasing refrigerant in larger quantities for professional service work.

Question 24: A centrifugal chiller's purge unit log shows an increase in air removal over the past month. What does this indicate?

The refrigerant charge is decreasing and should be topped off
The purge unit is malfunctioning and recovering too much gas
Normal variation based on load changes in the building
Increasing system leak rate allowing more air infiltration (Correct answer)

Correct answer: Increasing system leak rate allowing more air infiltration

Increasing purge unit operation on a centrifugal chiller is a key indicator of an increasing leak rate. As leaks allow more air to enter the vacuum-side system, the purge unit must run more frequently to remove the accumulated non-condensables. Technicians and building operators should monitor purge unit logs as an early leak detection tool — rising purge rates require immediate leak investigation.

Question 25: Do EPA Section 608 technician certifications expire?

They do not expire (Correct answer)
Every 5 years
Every 2 years
Every 10 years

Correct answer: They do not expire

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

Question 26: The sale of CFC-12 (R-12) in containers smaller than 20 pounds is restricted to whom?

Only technicians who are certified under Section 608.
Anyone, as long as it is for personal use.
Only licensed automotive repair shops.
Technicians who are certified under Section 609. (Correct answer)

Correct answer: Technicians who are certified under Section 609.

EPA regulations specifically state that the sale of ozone-depleting substances like CFC-12 in containers of less than 20 pounds is restricted to technicians who have been certified under an EPA-approved Section 609 program. Sellers are required to verify the purchaser's certification.

Question 27: 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 must be tested for moisture content only
It must be destroyed by an EPA-approved facility
It must be recycled or reclaimed to ARI 700 purity standards (Correct answer)
It can be recharged directly without any processing

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.

Question 28: The EPA offers awards of up to what amount for information leading to penalties against violators?

$50,000
$100
$1,000
$10,000 (Correct answer)

Correct answer: $10,000

The EPA may pay awards up to $10,000 for information leading to a penalty.

Question 29: Under EPA Section 609, which of the following actions is explicitly prohibited when servicing automotive air conditioning systems?

Checking system pressure with a manifold gauge set
Venting refrigerant directly into the atmosphere (Correct answer)
Using a refrigerant identifier before beginning service
Recovering refrigerant into an approved container

Correct answer: Venting refrigerant directly into the atmosphere

EPA Section 609 prohibits the knowing venting of refrigerants used in motor vehicle air conditioning systems into the atmosphere. This applies to all refrigerants including R-12, R-134a, and R-1234yf. Technicians must use approved recovery equipment.

Question 30: A technician notices the electronic detector alarms everywhere in a room. The best next step is to:

Replace the system
Increase the system pressure
Conclude the whole system leaks
Ventilate the area and recheck once background vapor clears (Correct answer)

Correct answer: Ventilate the area and recheck once background vapor clears

High background vapor must be ventilated so the detector can isolate the actual leak.

Question 31: A frost line forming partway along the evaporator or suction line most commonly indicates:

A failed micron gauge
Excess oil in the condenser
The system is fully charged and operating correctly
A restriction or low refrigerant charge (Correct answer)

Correct answer: A restriction or low refrigerant charge

Frost at an abnormal point often signals a restriction or undercharge causing localized pressure drop.

Question 32: A rupture disk in a low-pressure system will open at which of the following psig?

15 psig (Correct answer)
20 psig
10 psig
25 psig

Correct answer: 15 psig

Rupture disks are critical safety devices in low-pressure refrigeration systems, designed to prevent over-pressurization. EPA regulations mandate that these disks must open at 15 psig to safely release refrigerant. This specific pressure setting protects the system's components from damage and ensures the safety of personnel by preventing catastrophic failure.

Question 33: A person who holds _______ may sell refrigerant containers containing more than 20 pounds of refrigerant.

Section 608 certification
either Section 608 or Section 609 certification (Correct answer)
Section 609 certification

Correct answer: either Section 608 or Section 609 certification

To purchase refrigerant containers holding more than 20 pounds, a person must hold either a Section 608 or Section 609 certification. Section 608 certification is for stationary HVAC/R equipment, while Section 609 is for mobile air conditioning (MVAC) systems. Both certifications demonstrate that the individual has the necessary knowledge to handle refrigerants responsibly and legally.

Question 34: When evacuating a system, what is the minimum number of microns a vacuum pump must pull?

500 Microns (Correct answer)
500000 Microns
50000 Microns
5000 Microns

Correct answer: 500 Microns

When evacuating a system, a vacuum pump must pull down to at least 500 microns (or 29.92 inches Hg vacuum). This deep vacuum ensures that all non-condensable gases and moisture are removed from the system. Removing moisture is critical because it can freeze, cause corrosion, and react with refrigerants and oils, leading to system damage.

Question 35: When charging a blended refrigerant like R-410A into a Type II system, how should the refrigerant be introduced?

As a throttled liquid into the compressor's suction port.
It can be charged as either a liquid or vapor depending on ambient temperature.
As a vapor through the suction line with the system running.
As a liquid into the king valve or liquid line service port. (Correct answer)

Correct answer: As a liquid into the king valve or liquid line service port.

Blended refrigerants, such as those in the 400-series like R-410A, must be charged as a liquid to prevent fractionation. Fractionation is the separation of the different components of the blend, which would alter the refrigerant's properties and impair system performance. Charging as a liquid ensures the correct mixture enters the system.

Question 36: A technician is servicing a residential split-system air conditioner that uses HCFC-22. According to the Clean Air Act Section 608, what must the technician do with the refrigerant before making a major repair?

Vent the refrigerant to the atmosphere in a well-ventilated area.
Recover the refrigerant into a disposable cylinder and discard it.
Dilute the refrigerant with nitrogen before releasing it.
Recover the refrigerant using EPA-certified recovery equipment. (Correct answer)

Correct answer: Recover the refrigerant using EPA-certified recovery equipment.

Section 608 of the Clean Air Act strictly prohibits the intentional venting of refrigerants. Technicians must use EPA-approved recovery equipment to remove the refrigerant from the appliance before servicing or disposal to prevent its release into the atmosphere.

Question 37: Which type of leak detector is considered the most sensitive and can detect refrigerant concentrations in the parts-per-billion range?

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

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 38: The safest way to determine how much refrigerant is in a recovery cylinder is to:

Weigh the cylinder using a scale (Correct answer)
Read the pressure gauge only
Check the color of the cylinder
Estimate by feel

Correct answer: Weigh the cylinder using a scale

Weighing the cylinder on a scale is the accurate way to track the charge and avoid exceeding the 80% fill limit.

Question 39: Refrigerant recovered from an MVAC system may be returned to a vehicle only if it meets which requirement?

It is vented and replaced
It has been stored over 90 days
It is mixed with fresh oil
It is recycled to SAE purity standards or recovered for reclamation (Correct answer)

Correct answer: It is recycled to SAE purity standards or recovered for reclamation

Recovered refrigerant must be recycled to SAE purity standards before reuse in a vehicle.

Question 40: Before disposing of a small appliance such as a refrigerator, the final person in the disposal chain must:

Vent the remaining refrigerant slowly
Verify that refrigerant has been recovered and keep a signed statement on file (Correct answer)
Crush the appliance before recovery
Add new refrigerant to the system

Correct answer: Verify that refrigerant has been recovered and keep a signed statement on file

The last person in the disposal chain must ensure refrigerant was recovered and retain a signed verification statement.

Question 41: Before refrigerant can be sold to a different owner, it must be:

Reclaimed to ARI-700 standards (Correct answer)
Recovered only
Recycled on-site only
Vented and replaced

Correct answer: Reclaimed to ARI-700 standards

Refrigerant changing ownership must be reclaimed to ARI-700 purity by a certified reclaimer before resale.

Question 42: A technician who disposes of a high-pressure appliance must do what before final disposal?

Recover the refrigerant and verify required evacuation (Correct answer)
Vent the refrigerant slowly
Cut the lines immediately
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 43: R-12 (CFC-12) MVAC systems cannot simply be retrofitted with R-134a without which modification?

Converting to a compatible PAG oil and replacing o-rings and seals (Correct answer)
Installing a new evaporator coil designed for R-134a
Adding a second condenser to handle R-134a's higher pressures
Replacing the compressor with a larger unit

Correct answer: Converting to a compatible PAG oil and replacing o-rings and seals

R-12 systems use mineral oil or alkylbenzene oil, which is not compatible with R-134a. R-134a requires polyalkylene glycol (PAG) oil. When retrofitting an R-12 system, the mineral oil must be thoroughly flushed out and replaced with PAG oil. Additionally, the o-rings and seals in R-12 systems are often not compatible with R-134a and must be replaced to prevent leaks.

Question 44: Recovery equipment for R-134a is governed by which SAE standard?

SAE J639
SAE J1234
SAE J2210 (Correct answer)
SAE J1991

Correct answer: SAE J2210

SAE J2210 covers R-134a recovery/recycling equipment for MVAC.

Question 45: What is the recovery/evacuation requirement for a small high-pressure appliance containing less than 200 lbs with a non-operating compressor (post-1993 equipment)?

15 inches Hg vacuum
0 inches Hg vacuum
4 inches Hg vacuum (Correct answer)
10 inches Hg vacuum

Correct answer: 4 inches Hg vacuum

Appliances under 200 lbs with a non-operating compressor must be evacuated to 4 inches of mercury vacuum.

Question 46: Which refrigerant has both a non-zero ODP and a high GWP, making it subject to phaseout under both the Montreal Protocol and climate regulations?

R-744 (CO2)
R-22 (Correct answer)
R-410A
R-134a

Correct answer: R-22

R-22 (HCFC-22) has an ODP of 0.055 (non-zero, chlorine-containing) and a GWP of 1,810. This means it contributes to both ozone depletion and climate change, making it subject to phaseout under the Montreal Protocol's HCFC schedule. R-410A (HFC) has zero ODP but high GWP; R-134a (HFC) has zero ODP; CO2 has both zero ODP and a GWP of 1.

Question 47: In a refrigeration cycle, which component raises the refrigerant's pressure and temperature?

Condenser
Metering device
Evaporator
Compressor (Correct answer)

Correct answer: Compressor

The compressor increases both the pressure and temperature of the refrigerant vapor.

Question 48: Before opening a low-pressure appliance for service, the technician must first:

Add nitrogen to 100 psig
Run the compressor at full load
Vent it to the atmosphere
Recover the refrigerant to the required level (Correct answer)

Correct answer: Recover the refrigerant to the required level

Refrigerant must be recovered to the required vacuum before the system is opened.

Question 49: When charging a single-component refrigerant into an operating system, in what state should it enter the suction line?

Solid (dry ice)
Supercritical fluid
Liquid only
Vapor (gas) only (Correct answer)

Correct answer: Vapor (gas) only

Single-component refrigerants like R-22 can be safely charged as vapor into the suction line of a running system without risk of slugging the compressor.

Question 50: A high-pressure appliance with 50 lbs of charge that is not being disposed of must be repaired within how many days of a leak being detected?

60 days
30 days (Correct answer)
10 days
90 days

Correct answer: 30 days

Leaks on appliances with 50+ lbs of charge generally must be repaired within 30 days.

Question 51: What instrument is used to measure the depth of vacuum during system evacuation?

Micron gauge (electronic vacuum gauge) (Correct answer)
Refrigerant identifier
Thermometer
Manifold gauge set

Correct answer: Micron gauge (electronic vacuum gauge)

An electronic micron gauge measures vacuum in microns of mercury (µmHg), providing accurate readings below the range of standard manifold gauges.

Question 52: A technician recovers refrigerant from a system and stores it in a recovery cylinder. According to EPA Section 608, which of the following markings is REQUIRED on that cylinder?

The cylinder must be painted blue to distinguish it from new refrigerant
The cylinder must be labeled to identify the type of refrigerant it contains (Correct answer)
The cylinder must be tagged with the date of recovery and the system owner's name
The cylinder must display the technician's EPA certification number

Correct answer: The cylinder must be labeled to identify the type of refrigerant it contains

EPA regulations require that recovery cylinders be labeled with the type of refrigerant they contain. This prevents cross-contamination and ensures the refrigerant can be properly handled, recycled, or reclaimed downstream. Cylinders must also meet DOT specifications.

Question 53: Which refrigerant type has zero ozone depletion potential but can still have a high global warming potential?

Halons
HFCs (Correct answer)
HCFCs
CFCs

Correct answer: HFCs

HFCs contain no chlorine so have zero ODP, but many have high GWP.

Question 54: Which refrigerant property is most associated with global warming potential (GWP)?

Heat-trapping ability in the atmosphere (Correct answer)
Electrical conductivity
Ozone destruction
Toxicity to humans

Correct answer: Heat-trapping ability in the atmosphere

GWP measures how much heat a greenhouse gas traps in the atmosphere relative to carbon dioxide.

Question 55: What exactly does a sling psychrometer measure?

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

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 56: True or false: The receiver is not part of a refrigeration system's low side?

False
True (Correct answer)

Correct answer: True

This statement is true. The receiver in a refrigeration system is located on the high-pressure side, typically after the condenser and before the expansion device. Its purpose is to store excess liquid refrigerant, ensuring a continuous supply to the evaporator and preventing liquid from backing up into the condenser.

Question 57: Which component is present in all four types of vapor-compression refrigeration cycles (small appliances, high-pressure, low-pressure, and automotive)?

Compressor (Correct answer)
Receiver-drier
Accumulator
Purge unit

Correct answer: Compressor

All vapor-compression refrigeration systems — regardless of size, pressure, or application — require a compressor to circulate refrigerant through the cycle by compressing low-pressure vapor into high-pressure vapor. Receiver-driers are found in most but not all systems; accumulators are specific to certain configurations; purge units are unique to low-pressure centrifugal chillers.

Question 58: Under the Clean Air Act, what practice involving refrigerant is prohibited during service, maintenance, and disposal?

Knowingly venting (Correct answer)
Recycling
Reclaiming
Recovery

Correct answer: Knowingly venting

Knowingly venting refrigerant to the atmosphere is prohibited by law.

Question 59: Synthetic oils based on ester can be combined with other oils.

A) False (Correct answer)
B) True

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

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

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 61: Which leak detection method uses a UV-reactive dye injected into the refrigerant circuit to pinpoint the source of a leak?

Ultrasonic detection
Bubble solution test
Electronic leak detector
Fluorescent dye detection (Correct answer)

Correct answer: Fluorescent dye detection

Fluorescent dye detection involves injecting a UV-reactive dye into the system. When the dye escapes with leaking refrigerant, it glows under a UV or black light, allowing technicians to pinpoint the exact leak location. It is effective for finding small, intermittent leaks.

Question 62: Section 609 certification primarily focuses on which refrigerant handling skill?

Chiller teardown
Cryogenics
Ammonia handling
Proper recovery/recycling during MVAC service (Correct answer)

Correct answer: Proper recovery/recycling during MVAC service

Section 609 emphasizes proper recovery and recycling during motor vehicle AC service.

Question 63: Which certification did the 1990 Clean Air Act Amendments authorize for auto AC?

OSHA HVAC
Section 609 (Correct answer)
Type III
Section 608 Universal

Correct answer: Section 609

The 1990 amendments led to the Section 609 MVAC certification.

Question 64: Which refrigerant is commonly found in low-pressure appliances?

R-134a
R-410A
R-123 (Correct answer)
R-22

Correct answer: R-123

R-123 (and previously R-11) is a typical low-pressure refrigerant used in centrifugal chillers.

Question 65: Never pressurize a system with compressed air or oxygen because

when mixed with compressor oil or some refrigerants, it could explode. (Correct answer)
the pressure produced by either oxygen or compressed air are not as good as nitrogen pressures.
oxygen and compressed air do not mix with refrigerants.
leaking oxygen or compressed air is more difficult to detect than nitrogen.

Correct answer: when mixed with compressor oil or some refrigerants, it could explode.

Pressurizing a refrigeration system with compressed air or oxygen is extremely dangerous and strictly prohibited. When mixed with compressor oil or certain refrigerants, oxygen can create a highly combustible mixture, leading to a severe explosion. Nitrogen, an inert gas, is the safe and recommended choice for leak testing and purging.

Question 66: Which of the following refrigerants has the least or no potential for ozone depletion:

HCFCs
HFCs (Correct answer)
FCs
CFCs

Correct answer: HFCs

Hydrofluorocarbons (HFCs) have the least or no potential for ozone depletion because they do not contain chlorine atoms. Unlike CFCs and HCFCs, which release ozone-destroying chlorine in the stratosphere, HFCs are composed only of hydrogen, fluorine, and carbon. While HFCs are potent greenhouse gases, they are considered ozone-friendly alternatives.

Question 67: What unique challenge does a power outage present to a centrifugal chiller system operating at low pressure?

High pressure will build in the condenser when cooling water flow stops
Air can infiltrate through mechanical seals when the compressor stops and system pressure equilibrates below atmospheric (Correct answer)
The refrigerant will solidify in the evaporator without constant circulation
The compressor may restart in reverse rotation, causing damage

Correct answer: Air can infiltrate through mechanical seals when the compressor stops and system pressure equilibrates below atmospheric

When a centrifugal chiller loses power, the compressor stops and system pressure equilibrates. If the system pressure rises above local atmospheric pressure during warmup (some refrigerants), refrigerant may vent. More critically, as the system cools, pressure may drop below atmospheric again, potentially drawing air through shaft seals. Proper startup procedures after power outages include checking for air infiltration.

Question 68: Recovery/recycling equipment for R-12 must meet which standard?

SAE J1991 (Correct answer)
NFPA 70
ASHRAE 15
UL 1995

Correct answer: SAE J1991

SAE J1991 sets the standard for R-12 recovery and recycling equipment.

Question 69: A technician needs to perform a major repair on a high-pressure appliance containing 210 lbs of R-22 that was manufactured after November 15, 1993. What is the required evacuation level?

4 inches of Hg
15 inches of Hg
0 inches of Hg
10 inches of Hg (Correct answer)

Correct answer: 10 inches of Hg

For high-pressure appliances containing 200 pounds or more of refrigerant, and when using recovery/recycling equipment manufactured after November 15, 1993, the EPA requires evacuation to a level of 10 inches of Hg vacuum.

Question 70: Which agency administers and enforces the Section 608 refrigerant certification program?

OSHA
DOT
DOE
EPA (Correct answer)

Correct answer: EPA

The Environmental Protection Agency administers Section 608 of the Clean Air Act and its certification program.

Question 71: What DOT-approved color coding identifies a cylinder intended specifically for storing recovered, used, or contaminated refrigerant?

Gray body with yellow top (Correct answer)
Silver body with orange top
Green body with white top
Light blue body with white top

Correct answer: Gray body with yellow top

DOT-approved recovery cylinders for used or contaminated refrigerant are color-coded gray with a yellow top. This distinguishes them from cylinders of virgin refrigerant and prevents contaminated refrigerant from being mistakenly introduced into a clean system.

Question 72: Refrigerant contacting skin can cause which injury due to its rapid evaporation?

Chemical burns from acid
Electrical shock
Sunburn
Frostbite (Correct answer)

Correct answer: Frostbite

Liquid refrigerant evaporates quickly and can freeze skin tissue, causing frostbite.

Question 73: What refrigerant was the standard in household refrigerators and small appliances before the CFC phaseout?

R-11
R-22
R-12 (Correct answer)
R-502

Correct answer: R-12

R-12 (CFC-12, dichlorodifluoromethane) was the refrigerant of choice in household refrigerators, freezers, and small commercial refrigeration equipment for decades before the CFC phaseout. The U.S. phased out new production of R-12 by January 1, 1996, leading to the transition to R-134a and eventually R-600a in small appliances.

Question 74: When inspecting for leaks in various systems, which gas should be used?

Oxygen
Hydrogen
Nitrogen (Correct answer)
Carbon

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 75: Which refrigerant is most commonly associated with Type II high-pressure appliances?

R-11
R-22 (Correct answer)
R-12
R-123

Correct answer: R-22

R-22 is the classic high-pressure refrigerant covered under Type II certification.

Question 76: Which piece of equipment is designed to clean refrigerant on-site by removing oil, moisture, and other contaminants so it can be reused in a system owned by the same person?

A reclamation unit
A vacuum pump
A recovery cylinder
A recycling unit (Correct answer)

Correct answer: A recycling unit

Recycling equipment is used to clean refrigerant by extracting it and passing it through devices like filter-driers to reduce contaminants. This allows the refrigerant to be reused in equipment belonging to the same owner.

Question 77: To determine the type of refrigerant, which purity test is used?

ARI 200
ARI 900
ARI 500
ARI 700 (Correct answer)

Correct answer: ARI 700

AHRI Standard 700 is the industry standard that specifies the purity levels for refrigerants and also outlines the methods for testing and verifying refrigerant types and purity. This standard is crucial for ensuring that refrigerants, whether virgin or reclaimed, meet the necessary specifications for safe and effective use in HVAC/R systems.

Question 78: Which of the following is NOT considered a small appliance under Type I?

A vending machine
A dehumidifier
A window air conditioner
A split-system central air conditioner (Correct answer)

Correct answer: A split-system central air conditioner

Split-system central AC is field-assembled and not hermetically sealed, so it is not a Type I small appliance.

Question 79: Which law gives the EPA authority to regulate MVAC refrigerant servicing?

RCRA
TSCA
Clean Air Act (Correct answer)
Clean Water Act

Correct answer: Clean Air Act

The Clean Air Act provides EPA authority over MVAC refrigerant servicing.

Question 80: Under EPA Section 608, the prohibition on knowingly venting refrigerants during service, maintenance, repair, or disposal applies to which substances?

HCFCs only
CFCs and HCFCs only
CFCs, HCFCs, and their substitutes including HFCs (Correct answer)
CFCs only

Correct answer: CFCs, HCFCs, and their substitutes including HFCs

EPA extended the venting prohibition beyond CFCs and HCFCs to include substitute refrigerants such as HFCs (e.g., R-410A, R-134a). Knowingly venting any of these during service or disposal is illegal under Section 608.

Question 81: Which refrigerant was used in most vehicles built before 1994?

R-12 (Correct answer)
R-1234yf
R-134a
R-410A

Correct answer: R-12

R-12 (CFC-12) was the standard MVAC refrigerant before the mid-1990s.

Question 82: A technician discovers that an MVAC system contains an unknown or contaminated refrigerant. What is the proper procedure?

Mix the contaminated refrigerant with the shop's used R-134a and send it for reclamation.
Recover the refrigerant using a dedicated recover-only unit and store it in a separate, clearly marked tank. (Correct answer)
Vent the unknown refrigerant to the atmosphere in a well-ventilated area.
Use standard R-134a recovery equipment to remove the refrigerant.

Correct answer: Recover the refrigerant using a dedicated recover-only unit and store it in a separate, clearly marked tank.

Technicians must recover contaminated or unfamiliar refrigerants and are prohibited from venting them. The best practice is to use a separate, dedicated recovery machine and tank to prevent contamination of other equipment and refrigerants. The recovered contaminated refrigerant must be stored in a DOT-approved tank, properly labeled, and disposed of correctly.

Question 83: What is the main purpose of recovering refrigerant rather than venting it before servicing a system?

To reduce the weight of the appliance for shipping
To comply with the law and prevent release of ozone-depleting and greenhouse gases (Correct answer)
To increase the system's operating pressure
To convert the refrigerant into a non-regulated substance

Correct answer: To comply with the law and prevent release of ozone-depleting and greenhouse gases

Recovery is required by law to keep harmful refrigerants out of the atmosphere.

Question 84: When recovering refrigerant from a Type II system with an inoperative compressor, which of the following is a correct procedure?

Heat the compressor and strike it with a hammer.
Recover as much liquid refrigerant as possible from the liquid line first. (Correct answer)
Use a passive (system-dependent) recovery device.
Pressurize the system with nitrogen to force out the refrigerant.

Correct answer: Recover as much liquid refrigerant as possible from the liquid line first.

To expedite the recovery process from any system, especially one with a non-operational compressor, it is most efficient to remove the refrigerant in its liquid state first. Recovering from the liquid line allows for the removal of the densest form of the refrigerant, significantly speeding up the overall recovery time before recovering the remaining vapor.

Question 85: Under EPA Section 608, what is the primary purpose of the "safe disposal" requirements for small appliances?

To ensure technicians do not waste usable refrigerant by disposing of it
To require manufacturers to redesign systems for easier refrigerant access
To mandate energy efficiency testing before disposal
To ensure refrigerant is recovered before appliances are disposed of at scrap facilities (Correct answer)

Correct answer: To ensure refrigerant is recovered before appliances are disposed of at scrap facilities

The safe disposal requirements under Section 608 ensure that refrigerant is removed from small appliances (refrigerators, window ACs, etc.) before they are scrapped, crushed, or shredded at disposal facilities. Without these requirements, refrigerant would be released to the atmosphere as appliances are processed. The rules apply to both technicians and final disposal entities.

Question 86: Recovery equipment manufactured after November 15, 1993, must be certified to meet:

No standard
EPA/AHRI recovery efficiency standards for the appliance type (Correct answer)
Only state regulations
ASHRAE comfort standards

Correct answer: EPA/AHRI recovery efficiency standards for the appliance type

Recovery equipment made after Nov. 15, 1993 must be certified to meet EPA and AHRI recovery efficiency standards.

Question 87: PAG oil used in R-134a MVAC systems must be stored and handled carefully for which reason?

PAG oil is incompatible with rubber hoses and must only contact metal fittings
PAG oil reacts explosively with water at room temperature
PAG oil is highly hygroscopic and absorbs moisture rapidly from the atmosphere (Correct answer)
PAG oil must be kept below 40°F or it permanently loses its viscosity properties

Correct answer: PAG oil is highly hygroscopic and absorbs moisture rapidly from the atmosphere

PAG (polyalkylene glycol) oil is highly hygroscopic — it absorbs moisture from the air very rapidly when exposed. Moisture in refrigerant oil creates acid that damages compressor bearings, valves, and motor windings. Always keep PAG oil containers sealed when not in use, use clean dedicated equipment for oil handling, and minimize air exposure time during oil addition procedures.

Question 88: The _________ has created a standard for flammable refrigerant recovery and recovery/recycling machines.

EPA
ISRAE
SAE (Correct answer)
DOT

Correct answer: SAE

The Society of Automotive Engineers (SAE) has developed standards for flammable refrigerant recovery and recovery/recycling machines. These standards, such as SAE J2843 and J3030, ensure that equipment used for flammable refrigerants is designed and tested to operate safely and effectively. This is crucial for technician safety and environmental protection when handling these specific refrigerants.

Question 89: Self-contained (active) recovery equipment differs from system-dependent (passive) equipment because it:

Has its own compressor/pump to pull refrigerant from the appliance (Correct answer)
Relies on the appliance compressor to push refrigerant out
Can only be used on small appliances
Does not require EPA certification

Correct answer: Has its own compressor/pump to pull refrigerant from the appliance

Self-contained recovery equipment has its own means (compressor or pump) to draw refrigerant out, unlike passive equipment that depends on the system's own pressure.

Question 90: Under EPA Section 608 recordkeeping requirements, for how long must service records of refrigerant purchased and added to appliances with more than 50 pounds of charge be maintained?

5 years
2 years
1 year
3 years (Correct answer)

Correct answer: 3 years

EPA Section 608 requires owners of refrigerant-containing appliances with a charge greater than 50 pounds to maintain records of the amount of refrigerant added to each appliance, the date of service, and the name of the technician for at least 3 years. These records must be made available to EPA inspectors upon request.

Question 91: Recovered refrigerant from a small appliance may be reused without reclamation if it is returned to what?

The same system or another owned by the same person/company (Correct answer)
The wholesaler for resale
A different brand of equipment
Any customer

Correct answer: The same system or another owned by the same person/company

On-site recycled refrigerant can be reused in equipment owned by the same person without being reclaimed to ARI 700.

Question 92: What color is the high-pressure (liquid line) side gauge on a typical manifold gauge set?

Yellow
Red (Correct answer)
Green
Blue

Correct answer: Red

The red gauge reads the high-pressure side of the system.

Question 93: If a leak repair attempt fails verification, the owner must do which of the following?

Ignore it until next year
Vent the system and abandon it
Conduct a follow-up verification and possibly develop a retrofit/retire plan (Correct answer)
Top off the charge weekly

Correct answer: Conduct a follow-up verification and possibly develop a retrofit/retire plan

Failed repairs require follow-up verification and may require a retrofit or retirement plan.

Question 94: A low-pressure appliance normally operates with the low side:

At exactly atmospheric pressure
Above 500 psig
Under a vacuum (below atmospheric pressure) (Correct answer)
Above 200 psig

Correct answer: Under a vacuum (below atmospheric pressure)

Low-pressure systems often operate under a partial vacuum on the low side.

Question 95: Under EPA Section 609, who is permitted to purchase bulk quantities of refrigerant for use in MVAC systems?

Any person who owns a vehicle with an A/C system
Any business holding a contractor's license
Only EPA-certified technicians using approved equipment (Correct answer)
Anyone with a valid driver's license

Correct answer: Only EPA-certified technicians using approved equipment

Under Section 609, only technicians certified under an EPA-approved program and using approved recovery/recycling equipment may purchase refrigerant in containers larger than 2 pounds for MVAC service. This requirement ensures that refrigerant used in automotive A/C service is handled by trained individuals using proper equipment to prevent atmospheric venting.

Question 96: 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
80% efficiency
90% efficiency
System pressure must reach 15 inches of mercury vacuum (Correct answer)

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 97: 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?

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

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 98: Who is authorized to administer EPA Section 608 certification exams?

EPA-approved certifying organizations (Correct answer)
State DMVs
Any HVAC employer
Refrigerant suppliers

Correct answer: EPA-approved certifying organizations

Only EPA-approved certifying organizations may administer the exams.

Question 99: Which refrigerant is classified as an HCFC (hydrochlorofluorocarbon)?

R-22 (Correct answer)
R-134a
R-12
R-410A

Correct answer: R-22

R-22 is an HCFC (chlorodifluoromethane) because it contains hydrogen, chlorine, and fluorine; its chlorine content gives it an ODP of 0.055.

Question 100: A refrigerant is identified as having a boiling point of approximately -41°F at atmospheric pressure. Which refrigerant does this most closely match?

R-123 (boiling point +82°F)
R-22 (boiling point -41.4°F) (Correct answer)
R-134a (boiling point -15.1°F)
R-11 (boiling point +74.7°F)

Correct answer: R-22 (boiling point -41.4°F)

R-22 (HCFC-22, chlorodifluoromethane) has an atmospheric boiling point of approximately -41.4°F (-40.8°C), making it a high-pressure refrigerant that is a vapor at room temperature. R-11 and R-123 have boiling points well above 0°F, meaning they are liquids at room temperature and operate under vacuum. R-134a boils at -15.1°F. Knowing boiling points helps technicians understand system pressure behavior.

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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