3e151 CDC Set C/P Volume 1
Questions and Answers
- 1.
What type of heat when added to a substance causes a measured temperature change without a change of state?
- A.
Latent
- B.
Specific
- C.
Sensible
- D.
Generic
Correct Answer
C. SensibleExplanation
Sensible heat refers to the type of heat that causes a measurable change in temperature without causing a change in the state of a substance. This means that when sensible heat is added to a substance, its temperature increases or decreases, but the substance remains in the same physical state (solid, liquid, or gas). Sensible heat transfer occurs due to the transfer of thermal energy between objects or substances with different temperatures, resulting in a measurable change in temperature.Rate this question:
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- 2.
In which two parts of a refrigeration system does a pressure change take place?
- A.
Condenser and evaporator
- B.
Compressor and evaporator
- C.
Condenser and metering device
- D.
Compressor and metering device
Correct Answer
D. Compressor and metering deviceExplanation
In a refrigeration system, a pressure change takes place in the compressor and metering device. The compressor is responsible for compressing the refrigerant vapor, increasing its pressure and temperature. This high-pressure, high-temperature vapor then flows to the metering device, which reduces the pressure of the refrigerant and controls its flow rate into the evaporator. This pressure change is crucial for the refrigeration cycle to work effectively, as it allows the refrigerant to absorb heat in the evaporator and release it in the condenser.Rate this question:
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- 3.
What is the line to inlet relationship of refrigerant vapor travel as it leaves the evaporator?
- A.
Suction to condenser
- B.
Suction to compressor
- C.
Discharge to condenser
- D.
Discharge to compressor
Correct Answer
B. Suction to compressorExplanation
The correct answer is "Suction to compressor." In a refrigeration system, the suction line connects the evaporator outlet to the compressor inlet. This line carries the low-pressure refrigerant vapor from the evaporator to the compressor, where it is compressed and sent to the condenser for further cooling. Therefore, the suction line is responsible for transporting the refrigerant vapor from the evaporator to the compressor.Rate this question:
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- 4.
Which processes take place inside the condenser?
- A.
Desuperheating and compression
- B.
Desuperheating and condensing
- C.
Vaporization and desuperheating
- D.
Vaporization and condensing
Correct Answer
B. Desuperheating and condensingExplanation
Inside the condenser, two processes occur: desuperheating and condensing. Desuperheating refers to the process of reducing the temperature of superheated vapor, while condensing involves the transformation of vapor into a liquid state. These processes are essential for the functioning of the condenser, as they help to remove heat from the vapor and convert it back into a liquid form, allowing for the efficient operation of the overall system.Rate this question:
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- 5.
The reciprocating refrigeration compressor is designed to remove
- A.
Vapor refrigerant from the condenser and decrease the pressure
- B.
Vapor refrigerant from the evaporator and increase the pressure
- C.
Liquid refrigerant from the condenser and increase the pressure
- D.
Liquid refrigerant from the evaporator and increase the pressure
Correct Answer
B. Vapor refrigerant from the evaporator and increase the pressureExplanation
The reciprocating refrigeration compressor is designed to remove vapor refrigerant from the evaporator and increase the pressure. This is because the compressor plays a crucial role in the refrigeration cycle by compressing the low-pressure vapor refrigerant from the evaporator and raising its pressure. This high-pressure vapor refrigerant is then sent to the condenser where it can be condensed into a liquid state. Therefore, the correct answer is "vapor refrigerant from the evaporator and increase the pressure."Rate this question:
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- 6.
Which component is installed at the inlet of the evaporator?
- A.
Metering device
- B.
Accumulator
- C.
Compressor
- D.
Condenser
Correct Answer
A. Metering deviceExplanation
The metering device is installed at the inlet of the evaporator. This component is responsible for regulating the flow of refrigerant into the evaporator, ensuring that the correct amount of refrigerant enters the system. By controlling the flow, the metering device helps to maintain the desired temperature and pressure within the evaporator, allowing for efficient heat transfer and cooling.Rate this question:
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- 7.
In which major component does absorbed heat cause liquid refrigerant to boil?
- A.
Metering device
- B.
Compressor
- C.
Condenser
- D.
Evaporator
Correct Answer
D. EvaporatorExplanation
The absorbed heat causes the liquid refrigerant to boil in the evaporator. The evaporator is responsible for absorbing heat from the surroundings, such as the air in a room, and this heat causes the liquid refrigerant to evaporate and turn into a gas. This gas then travels to the compressor where it is pressurized and sent to the condenser to release the heat before returning to the evaporator to repeat the cycle.Rate this question:
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- 8.
Which major component is considered to be the "heart" of the refrigeration system?
- A.
Metering device
- B.
Compressor
- C.
Evaporator
- D.
Condenser
Correct Answer
B. CompressorExplanation
The compressor is considered to be the "heart" of the refrigeration system because it is responsible for compressing the refrigerant gas, raising its pressure and temperature. This high-pressure gas is then sent to the condenser where it releases heat and becomes a high-pressure liquid. The compressor plays a crucial role in the refrigeration cycle by circulating the refrigerant and maintaining the flow of heat transfer throughout the system. Without the compressor, the refrigeration system would not be able to function properly.Rate this question:
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- 9.
Which refrigeration compressor is equipped with pistons and connecting rods?
- A.
Screw
- B.
Scroll
- C.
Centrifugal
- D.
Reciprocating
Correct Answer
D. ReciprocatingExplanation
A reciprocating refrigeration compressor is equipped with pistons and connecting rods. This type of compressor uses a piston-cylinder arrangement to compress the refrigerant by reciprocating motion. As the piston moves back and forth, it compresses the refrigerant gas, which is then discharged into the condenser. The reciprocating compressor is commonly used in small to medium-sized refrigeration and air conditioning systems due to its efficiency and reliability.Rate this question:
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- 10.
Which type piston can suction gas pass through?
- A.
Plug
- B.
Trunk
- C.
Plate
- D.
Forged
Correct Answer
B. TrunkExplanation
A trunk piston is designed with a cavity or trunk in the center, allowing the gas to pass through it. This type of piston is commonly used in internal combustion engines, where the gas needs to flow through the piston during the intake stroke. The trunk design enables efficient suction of the gas into the combustion chamber. Therefore, a trunk piston is the correct type of piston that allows gas to pass through.Rate this question:
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- 11.
How does the rotary compressor compress the refrigerant vapor?
- A.
Rotating action
- B.
Squeezing action
- C.
Increasing the volume
- D.
Decreasing the pressure
Correct Answer
B. Squeezing actionExplanation
The rotary compressor compresses the refrigerant vapor through a squeezing action. This means that the compressor uses rotating action to squeeze the vapor, reducing its volume and increasing its pressure. As the vapor is squeezed, its molecules are forced closer together, resulting in a higher pressure. This process is essential for the efficient operation of the refrigeration system, as it allows the vapor to be condensed and cooled before being circulated again.Rate this question:
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- 12.
What type of rotary compressor has the blade set into the cylinder?
- A.
Multiblade
- B.
Movable blade
- C.
Stationary blade
- D.
Eccentric roller blade
Correct Answer
C. Stationary bladeExplanation
A rotary compressor with a stationary blade has the blade set into the cylinder. This means that the blade remains fixed in position while the cylinder rotates, allowing for the compression of air or gas. The stationary blade helps to create a seal and control the flow of the medium being compressed. This type of compressor is commonly used in various applications, including refrigeration and air conditioning systems.Rate this question:
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- 13.
Which compressor type is used with refrigerants that have a large gas volume?
- A.
Reciprocating
- B.
Centrifugal
- C.
Screw
- D.
Scroll
Correct Answer
B. CentrifugalExplanation
Centrifugal compressors are used with refrigerants that have a large gas volume. These compressors are specifically designed to handle high flow rates and are efficient in compressing large volumes of gas. They work by converting kinetic energy into pressure energy, making them suitable for applications where a large gas volume needs to be compressed, such as in industrial refrigeration systems or large-scale air conditioning units.Rate this question:
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- 14.
Which type of compressor uses an orbiting motion for compression?
- A.
Reciprocating
- B.
Rotary
- C.
Screw
- D.
Scroll
Correct Answer
D. ScrollExplanation
A scroll compressor uses an orbiting motion for compression. It consists of two spiral-shaped scrolls, one fixed and one orbiting, which creates a series of gas pockets that gradually decrease in size, compressing the gas. This design allows for smooth and efficient compression without the need for valves, making scroll compressors quieter and more reliable compared to other types of compressors.Rate this question:
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- 15.
Heat that is picked up in the refrigeration system is rejected at the
- A.
Condenser
- B.
evaporator
- C.
compressor
- D.
metering device
Correct Answer
A. CondenserExplanation
In a refrigeration system, the condenser is responsible for the heat rejection process. After the refrigerant has absorbed heat from the evaporator, it enters the condenser where it releases the heat to the surrounding environment, typically through a set of coils or fins. This allows the refrigerant to cool down and return to a liquid state, ready to repeat the cooling cycle. Therefore, the correct answer is the condenser.Rate this question:
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- 16.
The advantage of an air-cooled condenser is
- A.
greater operating costs
- B.
higher head pressures
- C.
Fans that can become noisy
- D.
Less maintenance
Correct Answer
D. Less maintenanceExplanation
An air-cooled condenser has the advantage of requiring less maintenance compared to other types of condensers. This is because it does not require water or other external cooling sources, making it easier to maintain and reducing the need for regular inspections and repairs. Additionally, there are no concerns about water leaks or water treatment, further reducing the maintenance requirements.Rate this question:
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- 17.
The disadvantage of water-cooled condensers is
- A.
Lower head pressure
- B.
High heat transfer
- C.
Compactness
- D.
Higher cost
Correct Answer
D. Higher costExplanation
Water-cooled condensers have the disadvantage of higher cost compared to other types of condensers. This is because water-cooled condensers require additional equipment such as cooling towers, pumps, and water treatment systems, which can increase the overall cost of the system. Additionally, the installation and maintenance of water-cooled condensers can be more expensive compared to air-cooled condensers, further contributing to their higher cost.Rate this question:
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- 18.
Which type of water-cooled condenser has removable heads that allow the tubes to be cleaned out with a revolving brush?
- A.
Tube-within-a-tube
- B.
Shell-and-tube
- C.
Shell-and-coil
- D.
Double-tube
Correct Answer
B. Shell-and-tubeExplanation
A shell-and-tube water-cooled condenser has removable heads that allow the tubes to be cleaned out with a revolving brush. In this type of condenser, the water flows through the tubes while the refrigerant flows around the tubes in a shell. The removable heads make it easier to access and clean the tubes, ensuring efficient heat transfer between the refrigerant and the water.Rate this question:
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- 19.
The thermostatic expansion valve maintains a fully active evaporator by
- A.
Reducing heat load
- B.
Enhancing condensation
- C.
Maintaining the proper amount of superheat
- D.
Maintaining the proper amount of subcooling
Correct Answer
C. Maintaining the proper amount of superheatExplanation
The thermostatic expansion valve is responsible for regulating the flow of refrigerant into the evaporator coil. It does this by sensing the temperature of the refrigerant leaving the evaporator and adjusting the size of the valve opening accordingly. By maintaining the proper amount of superheat, which is the temperature difference between the refrigerant vapor and its saturation temperature, the expansion valve ensures that the evaporator is operating efficiently. This helps to prevent the formation of liquid refrigerant in the evaporator, which can cause a loss of cooling capacity and potential damage to the compressor.Rate this question:
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- 20.
Complete vaporization in an evaporator occurs at point
- A.
C
- B.
G
- C.
S
- D.
V
Correct Answer
D. VExplanation
The correct answer is V because complete vaporization in an evaporator occurs at the vapor outlet point, where all the liquid has been evaporated and only vapor is present.Rate this question:
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- 21.
What type of thermostatic expansion valve has a bulb that is charged with fluid that is different from the refrigerant in the system?
- A.
Gas
- B.
Cross
- C.
Liquid
- D.
Special
Correct Answer
B. CrossExplanation
A cross type thermostatic expansion valve has a bulb that is charged with fluid that is different from the refrigerant in the system. This allows for more precise control of the refrigerant flow as the fluid in the bulb expands and contracts with temperature changes, providing accurate feedback to the valve. This type of valve is commonly used in systems where precise temperature control is required.Rate this question:
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- 22.
What type of thermostatic expansion valve has a charged sensing bulb that presents the danger of flood-back?
- A.
Gas
- B.
Cross
- C.
Liquid
- D.
Special
Correct Answer
C. LiquidExplanation
A thermostatic expansion valve with a charged sensing bulb that presents the danger of flood-back is a "Liquid" type. In this type of valve, the sensing bulb is filled with a liquid charge, which can cause flood-back if not properly controlled. Flood-back occurs when liquid refrigerant enters the compressor, leading to potential damage. Therefore, a liquid type thermostatic expansion valve requires careful monitoring and control to prevent flood-back.Rate this question:
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- 23.
To create the required pressure drop, the capillary tube uses a designed
- A.
Reactance
- B.
Resistance
- C.
Flow increase
- D.
Pressure increase
Correct Answer
B. ResistanceExplanation
The capillary tube creates the required pressure drop by using resistance. Resistance is the opposition to the flow of fluid through the tube, and by designing the capillary tube with a specific level of resistance, the desired pressure drop can be achieved. This resistance helps to regulate the flow rate and pressure of the fluid passing through the tube.Rate this question:
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- 24.
How is the capillary tube in a system affected by the refrigerant charge?
- A.
The refrigerant charge is critical
- B.
The refrigerant pressure can fluctuate
- C.
The system can take extra refrigerant
- D.
The system can take a less amount of refrigerant
Correct Answer
A. The refrigerant charge is criticalExplanation
The refrigerant charge refers to the amount of refrigerant present in the system. If the charge is not at the correct level, it can have a significant impact on the performance of the system, including the capillary tube. The capillary tube is responsible for regulating the flow of refrigerant through the system. If the refrigerant charge is too high or too low, it can cause the capillary tube to become ineffective in controlling the flow, leading to issues such as improper cooling or inefficient operation. Therefore, it is crucial to ensure that the refrigerant charge is at the correct level for optimal system performance.Rate this question:
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- 25.
The direct-expansion evaporator picks up or absorbs heat directly from the
- A.
Outside air
- B.
Conditioned space
- C.
Primary refrigerant
- D.
Secondary refrigerant
Correct Answer
B. Conditioned spaceExplanation
The direct-expansion evaporator picks up or absorbs heat directly from the conditioned space. This means that the evaporator is located within the conditioned space, such as inside an air conditioning unit or a refrigeration system. It is responsible for absorbing heat from the air or the space being cooled, and transferring it to the refrigerant. This allows the refrigerant to evaporate and carry the heat away, resulting in a cooling effect in the conditioned space.Rate this question:
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- 26.
Which evaporator operating condition uses air circulation to aid in defrosting?
- A.
Frosting
- B.
Defrosting
- C.
Nonfrosting
- D.
Partial Frosting
Correct Answer
B. DefrostingExplanation
Defrosting is the evaporator operating condition that uses air circulation to aid in defrosting. During the defrosting process, the air circulation helps to melt the frost that has accumulated on the evaporator coils. This is typically achieved by temporarily reversing the direction of the refrigerant flow or by using electric heaters to warm the coils. The air circulation helps to distribute the warm air evenly across the coils, speeding up the defrosting process and ensuring efficient operation of the evaporator.Rate this question:
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- 27.
Which evaporator type is designed to maintain an even temperature throughout the refrigerated space?
- A.
Bare-tube
- B.
Finned-tube
- C.
Forced-convection
- D.
Natural-convection
Correct Answer
C. Forced-convectionExplanation
Forced-convection evaporators are designed to maintain an even temperature throughout the refrigerated space. This type of evaporator uses a fan or blower to circulate air over the evaporator coil, ensuring that the cold air is evenly distributed throughout the space. The forced convection helps to prevent any temperature variations, ensuring that all areas of the refrigerated space are kept at the desired temperature. This is particularly important in applications where temperature consistency is critical, such as in food storage or pharmaceuticals.Rate this question:
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- 28.
Which cooler is used exclusively to cool liquids?
- A.
Baudelot
- B.
Tank-type
- C.
Shell-and-coil
- D.
Shell-and-tube
Correct Answer
A. BaudelotExplanation
The Baudelot cooler is used exclusively to cool liquids. This type of cooler is specifically designed to efficiently cool liquids by circulating them through a series of tubes or coils. The liquid flows through the tubes while a cooling medium, such as water or air, passes over the exterior of the tubes, extracting heat and cooling the liquid. This design allows for effective heat transfer and cooling of the liquid, making the Baudelot cooler ideal for applications where liquid cooling is required.Rate this question:
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- 29.
Which type of cooler is generally used in the common water cooler?
- A.
Shell-and-coil
- B.
Shell-and-tube
- C.
Baudelot
- D.
Tank-type
Correct Answer
A. Shell-and-coilExplanation
The correct answer is Shell-and-coil. In a common water cooler, a shell-and-coil type of cooler is generally used. This type of cooler consists of a coil of tubing placed inside a shell. The water flows through the coil while the cooling medium, such as refrigerant or chilled water, circulates around the coil in the shell. This design allows for efficient heat transfer between the water and the cooling medium, resulting in the cooling of the water in the cooler.Rate this question:
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- 30.
Refrigerants containing chlorine are said to destroy
- A.
Ozone
- B.
Carbon
- C.
Oxygen
- D.
Nitrogen
Correct Answer
A. OzoneExplanation
Refrigerants containing chlorine are known to destroy ozone. This is because chlorine atoms can break apart ozone molecules in the stratosphere, resulting in a depletion of the ozone layer. This process is known as ozone depletion. The destruction of ozone can have harmful effects on the environment and human health, as it allows more ultraviolet (UV) radiation from the sun to reach the Earth's surface. Therefore, it is important to use refrigerants that do not contain chlorine to prevent further damage to the ozone layer.Rate this question:
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- 31.
R-406a can be used to replace
- A.
R-502
- B.
R-113
- C.
R-22
- D.
R-12
Correct Answer
D. R-12Explanation
R-406a can be used to replace R-12 because R-12 is a hydrochlorofluorocarbon (HCFC) refrigerant that has been phased out due to its harmful effects on the ozone layer. R-406a is a blend of refrigerants that does not contain any ozone-depleting substances and has similar properties to R-12. Therefore, it can be used as a suitable alternative to R-12 in various refrigeration and air conditioning systems.Rate this question:
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- 32.
Temperature glide in an zeotropic refrigerant means that the refrigerant is a
- A.
Blend that acts as one inside the refrigeration system
- B.
Mixture that acts as one while inside the refrigeration system
- C.
Blend that evaporates and condenses over a range of temperatures instead of a single temperature
- D.
Mixture that liquefies and vaporizes over a range of temperatures instead of a single temperature
Correct Answer
C. Blend that evaporates and condenses over a range of temperatures instead of a single temperatureExplanation
The correct answer is "blend that evaporates and condenses over a range of temperatures instead of a single temperature." Temperature glide refers to the phenomenon where a zeotropic refrigerant undergoes both evaporation and condensation over a range of temperatures, rather than at a single temperature. This is due to the presence of different components with varying boiling and condensing points in the refrigerant blend.Rate this question:
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- 33.
Which of these refrigerants has an ozone depletion rating of zero?
- A.
R-12
- B.
R-22
- C.
R-134a
- D.
R-500
Correct Answer
C. R-134aExplanation
R-134a is the correct answer because it has an ozone depletion rating of zero. This means that it does not contribute to the depletion of the ozone layer. R-12 and R-22, on the other hand, have ozone depletion potentials and can harm the ozone layer. R-500 was not mentioned in relation to its ozone depletion rating, so it cannot be determined if it has a rating of zero or not.Rate this question:
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- 34.
The Environmental Protection Agency (EPA) has developed a Significant New Alternatives Policy (SNAP) Program. This program is used to determine
- A.
Whether the alternative refrigerant provides adequate performance
- B.
the risks that alternative refrigerants pose to human health and the environment.
- C.
whether the alternative refrigerant is compatible with components of the system
- D.
The procedures necessary for retrofitting with refrigerants on the SNAP Program list
Correct Answer
B. the risks that alternative refrigerants pose to human health and the environment.Explanation
The EPA's Significant New Alternatives Policy (SNAP) Program is developed to assess the risks that alternative refrigerants pose to human health and the environment. The program aims to determine whether the alternative refrigerant is safe and does not have adverse effects on human health or the environment. By evaluating the risks associated with alternative refrigerants, the EPA can make informed decisions on which refrigerants can be used as substitutes for harmful substances, promoting environmental protection and public health.Rate this question:
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- 35.
Which organization requires that a comprehensive risk assessment be performed to estimate the likelihood of fire and potential results should a fire occur when alternative refrigerants contain a flammable component?
- A.
Air-Conditioning and Refrigerant Institute (ARI)
- B.
Environmental Protection Agency (EPA)
- C.
American Society of Testing Materials (ASTM)
- D.
American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE)
Correct Answer
B. Environmental Protection Agency (EPA)Explanation
The Environmental Protection Agency (EPA) requires a comprehensive risk assessment to be performed in order to estimate the likelihood of fire and potential results if a fire were to occur when alternative refrigerants contain a flammable component. This is because the EPA is responsible for regulating and enforcing environmental laws and regulations, including those related to the use and handling of hazardous substances such as refrigerants. By requiring a risk assessment, the EPA aims to ensure that proper safety measures are in place to prevent and mitigate the risks associated with flammable refrigerants.Rate this question:
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- 36.
What is the maximum fine and jail sentence that service technicians may be subject to for charging a system with an unacceptable refrigerant?
- A.
$10,000 and 5 years
- B.
$10,000 and 10 years
- C.
$25,000 and 5 years
- D.
$25,000 and 10 years
Correct Answer
C. $25,000 and 5 yearsExplanation
Service technicians may be subject to a maximum fine of $25,000 and a jail sentence of 5 years for charging a system with an unacceptable refrigerant.Rate this question:
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- 37.
Which of these refrigerants is colorless and has a very pronounced odor?
- A.
R-718
- B.
R-717
- C.
R-504
- D.
R-123
Correct Answer
B. R-717Explanation
R-717, also known as ammonia, is a colorless refrigerant with a very pronounced odor. It is commonly used in industrial refrigeration systems due to its high efficiency and low environmental impact. Ammonia has a strong smell that is easily detectable, even in small concentrations, which makes it a safe choice as any leaks can be quickly identified.Rate this question:
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- 38.
What is the maximum percent a refillable cylinder can be refilled with refrigerant?
- A.
85
- B.
80
- C.
75
- D.
70
Correct Answer
B. 80Explanation
The maximum percent a refillable cylinder can be refilled with refrigerant is 80%. This means that the cylinder can be filled up to 80% of its total capacity with refrigerant. Refilling the cylinder beyond this limit may cause safety issues or damage to the cylinder. It is important to follow this guideline to ensure proper functioning and safety when handling refrigerants.Rate this question:
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- 39.
A good refrigerant oil will have
- A.
A high pour point
- B.
Thermal instability
- C.
Chemical reaction
- D.
Low viscosity
Correct Answer
B. Thermal instability -
- 40.
Which refrigerant oil is designed for use with the new ternary blend refrigerants?
- A.
Ester
- B.
Mineral
- C.
Polyalkylene glycol
- D.
Alkyl benzene oil
Correct Answer
D. Alkyl benzene oilExplanation
Alkyl benzene oil is designed for use with the new ternary blend refrigerants. It is a synthetic oil that offers excellent lubricity and stability, making it suitable for use in refrigeration systems. Alkyl benzene oil is compatible with various refrigerants, including the new ternary blend refrigerants, and helps to ensure efficient and reliable operation of the system.Rate this question:
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- 41.
Cleaning a refrigerant at the job site or at a local service shop is called
- A.
Recycling
- B.
Reclamation
- C.
Redeeming
- D.
Recovery
Correct Answer
A. RecyclingExplanation
The process of cleaning a refrigerant at the job site or at a local service shop is referred to as recycling. This involves removing any impurities or contaminants from the refrigerant to make it suitable for reuse. Recycling helps to minimize waste and conserve resources by extending the lifespan of the refrigerant, reducing the need for new refrigerant production.Rate this question:
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- 42.
On systems that contain over how many pounds of refrigerant is passive recovery not authorized?
- A.
7.5
- B.
10
- C.
12
- D.
15
Correct Answer
D. 15Explanation
Passive recovery refers to the process of recovering refrigerant without the use of a recovery machine. It relies on the natural movement of refrigerant from a system to a recovery cylinder. According to the given answer, passive recovery is not authorized for systems that contain over 15 pounds of refrigerant. This means that for systems with more than 15 pounds of refrigerant, a recovery machine must be used to safely and efficiently recover the refrigerant.Rate this question:
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- 43.
On Type II systems, what level of evacuation in the isolated component must be attained when you are making minor repairs of items such as a filter-drier or a strainer?
- A.
0 pounds per square inch gauge (psig)
- B.
5 psig
- C.
4 inches of mercury
- D.
10 inches of mercury
Correct Answer
A. 0 pounds per square inch gauge (psig)Explanation
When making minor repairs on Type II systems, such as replacing a filter-drier or a strainer, the isolated component must be evacuated to a level of 0 pounds per square inch gauge (psig). This means that the component should be completely free of any pressure. This is necessary to ensure that there are no contaminants or moisture left in the system, which could affect its performance. Evacuating the component to 0 psig helps maintain the efficiency and reliability of the system.Rate this question:
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- 44.
Commercial and industrial systems with leaks exceeding what percent per year will require repair?
- A.
5
- B.
15
- C.
25
- D.
35
Correct Answer
D. 35Explanation
Commercial and industrial systems with leaks exceeding 35% per year will require repair. This means that if the leaks in the system exceed 35% of the total volume per year, it is necessary to fix the leaks. This is because leaks can lead to significant loss of resources and can also cause damage to the system itself. Therefore, it is important to address and repair any leaks that exceed this threshold to ensure the proper functioning and efficiency of the commercial or industrial system.Rate this question:
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- 45.
R–401A is not a suitable alternative refrigerant for
- A.
Walk-in coolers
- B.
Home refrigerators
- C.
Supermarket display cases
- D.
Residential air conditioners
Correct Answer
D. Residential air conditionersExplanation
R-401A is not a suitable alternative refrigerant for residential air conditioners because it is primarily designed for low-temperature applications, such as walk-in coolers and supermarket display cases. Residential air conditioners require a refrigerant that is specifically formulated for higher operating temperatures and pressures. Using R-401A in residential air conditioners could lead to inefficient cooling, potential damage to the system, and increased energy consumption.Rate this question:
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- 46.
R–401A and B can be described as a/an
- A.
Blend-type alternative
- B.
Azeotrope alternative
- C.
Chlorofluorocarbon (CFC) - based alternative
- D.
Hydrofluorocarbon (HFC)-based alternative
Correct Answer
D. Hydrofluorocarbon (HFC)-based alternativeExplanation
R-401A and B are described as hydrofluorocarbon (HFC)-based alternatives. This means that they are alternatives that use HFCs as their primary components. HFCs are a type of synthetic refrigerant that does not contain chlorine, making them less harmful to the ozone layer compared to chlorofluorocarbons (CFCs). HFC-based alternatives are commonly used in refrigeration and air conditioning systems as a more environmentally friendly option.Rate this question:
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- 47.
Which alternative replacement for R–502 is a patented azeotrope?
- A.
R-507
- B.
R-409A
- C.
R-404A
- D.
R-402A
Correct Answer
A. R-507Explanation
R-507 is a patented azeotrope alternative replacement for R-502. This means that R-507 is a mixture of two or more refrigerants that behave as a single substance, providing similar cooling properties as R-502. It is protected by a patent, indicating that it is a proprietary blend and cannot be replicated or used without permission. Therefore, R-507 is the correct answer as it meets the criteria of being a patented azeotrope replacement for R-502.Rate this question:
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- 48.
You are retrofitting a system that does not have a receiver. To do the job properly, you would store the refrigerant in
- A.
A recovery cylinder
- B.
The compressor
- C.
The condenser
- D.
The evaporator
Correct Answer
A. A recovery cylinderExplanation
To retrofit a system without a receiver properly, the refrigerant should be stored in a recovery cylinder. A recovery cylinder is designed to safely store and transport refrigerant during the retrofitting process. It allows for the proper handling and disposal of the refrigerant, ensuring that it does not escape into the atmosphere and cause environmental harm. Storing the refrigerant in the compressor, condenser, or evaporator would not be appropriate or effective for the retrofitting process.Rate this question:
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- 49.
When polyolester oil is used in place of mineral oil during a retrofit procedure, you must make sure that less than what percent of mineral oil can remain in the system?
- A.
5
- B.
4
- C.
3
- D.
2
Correct Answer
A. 5Explanation
During a retrofit procedure, when polyolester oil is used instead of mineral oil, it is crucial to ensure that less than 5% of mineral oil remains in the system. This is because the two types of oils have different properties and mixing them can lead to issues such as reduced lubrication efficiency and potential damage to the system components. Therefore, it is important to thoroughly flush the system and remove as much mineral oil as possible before using polyolester oil.Rate this question:
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- 50.
You are retrofitting a system with an alternative refrigerant and you determine that the capillary tube must be replaced. To do the job correctly, you would replace the capillary tube with one having
- A.
Greater resistance and shorter length
- B.
Lesser resistance and shorter length
- C.
Greater resistance and longer length
- D.
Lesser resistance and longer length
Correct Answer
C. Greater resistance and longer lengthExplanation
When retrofitting a system with an alternative refrigerant, replacing the capillary tube with one having greater resistance and longer length is the correct approach. A capillary tube controls the flow of refrigerant into the evaporator coil. By increasing the resistance and length of the capillary tube, the flow rate of the refrigerant is reduced. This is necessary when using an alternative refrigerant, as it may have different pressure and flow characteristics compared to the original refrigerant. Adjusting the capillary tube in this way ensures proper functioning of the system with the new refrigerant.Rate this question:
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Current Version
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Mar 20, 2023Quiz Edited by
ProProfs Editorial Team -
Jan 25, 2017Quiz Created by
Patricklittle101
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