1.
When moisture is present in a refrigeration system, it will react with the refrigerant and the oil to form ________.
Correct Answer
B. Acid
Explanation
When moisture is present in a refrigeration system, it will react with the refrigerant and the oil to form acid. Moisture can cause chemical reactions with the refrigerant and oil, leading to the formation of acidic compounds. This can be detrimental to the system as acids can corrode the components, reduce efficiency, and potentially cause system failure. Therefore, it is important to ensure that refrigeration systems are properly sealed and free from moisture to prevent the formation of acids.
2.
Which of the following represents the lowest vacuum?
Correct Answer
D. 1000 microns
Explanation
The answer "1000 microns" represents the lowest vacuum because microns are a unit of measurement commonly used to measure vacuum levels. A higher number of microns indicates a lower vacuum level, so 1000 microns would represent a lower vacuum compared to the other options provided.
3.
To pull a vacuum means to ________.
Correct Answer
B. Lower the pressure in a refrigeration system below atmospHeric
Explanation
To pull a vacuum means to lower the pressure in a refrigeration system below atmospheric. This process is typically done to remove air and moisture from the system, creating a vacuum environment. By lowering the pressure, any unwanted gases or impurities can be eliminated, allowing for better performance and efficiency in the refrigeration system.
4.
A compound gauge ________.
Correct Answer
D. All of the above
Explanation
The compound gauge is a type of gauge that can indicate pressures above 14.696 psia, pressures in inches Hg below atmospheric pressure, and is also one of the two gauges on a typical gauge manifold. Therefore, the correct answer is "all of the above".
5.
A micron gauge is used to measure
Correct Answer
C. Absolute pressures below 1 mm Hg
Explanation
A micron gauge is a device used to measure pressures that are extremely low, specifically pressures below 1 mm Hg. This means it is capable of measuring pressures that are close to a vacuum or very close to atmospheric pressure. The other options, such as measuring atmospheric pressures at high altitudes or sea level, or measuring high pressure in a refrigeration system, are not within the range of measurement capabilities of a micron gauge. Therefore, the correct answer is that a micron gauge is used to measure absolute pressures below 1 mm Hg.
6.
The best method of leak checking is when the refrigeration system is ________.
Correct Answer
D. Standing with dry nitrogen pressure of 150 psig in the system
Explanation
The best method of leak checking is when the refrigeration system is standing with dry nitrogen pressure of 150 psig in the system. This method allows for the detection of any leaks in the system by pressurizing it with dry nitrogen. By pressurizing the system, any leaks will cause a drop in pressure, indicating the location of the leak. This method is effective in identifying and locating leaks in the refrigeration system.
7.
Noncondensable gases ________.
Correct Answer
B. Are undesirable in a refrigeration system
Explanation
Noncondensable gases are undesirable in a refrigeration system because they can interfere with the heat transfer process. These gases do not condense into a liquid state like the refrigerant, which can lead to reduced efficiency and performance of the system. Noncondensable gases can also cause issues such as increased pressure, reduced cooling capacity, and potential damage to the compressor. Therefore, it is important to remove these gases from the system to ensure optimal operation and prevent any potential problems.
8.
What is the most accurate instrument for checking a deep vacuum?
Correct Answer
D. Electronic vacuum gauge
Explanation
An electronic vacuum gauge is the most accurate instrument for checking a deep vacuum because it uses electronic sensors to measure the pressure, providing precise and reliable readings. Unlike other options, such as a compound gauge or mercury-based instruments, an electronic vacuum gauge does not rely on mechanical or fluid-based systems that may be prone to errors or inaccuracies. Therefore, it is the preferred choice when high accuracy is required for measuring deep vacuum levels.
9.
To insure accurate testing, the best material to use for connecting lines to the vacuum pump and gauge set is ________.
Correct Answer
C. Copper tube
Explanation
Copper tube is the best material to use for connecting lines to the vacuum pump and gauge set because it is a durable and non-reactive material that can withstand high pressure and vacuum conditions. It provides a tight and secure connection, ensuring accurate testing without any leakage or contamination. Copper tube is also resistant to corrosion, which makes it suitable for long-term use in testing applications.
10.
A multiple evacuation means that ________.
Correct Answer
C. You pull a vacuum on a refrigeration system more than once, allowing refrigerant or nitrogen into the system between each procedure
11.
Moisture in a liquid state must be ________ before it can be removed with a vacuum pump.
Correct Answer
A. Vaporized
Explanation
Before moisture can be removed with a vacuum pump, it needs to be converted into a vapor state. This is because a vacuum pump works by creating a low-pressure environment, which allows the vaporized moisture to be drawn out more effectively. Therefore, the correct answer is "vaporized."
12.
How many chlorine atoms does it take to destroy 100,000 ozone molecules in the stratosphere?
Correct Answer
B. 1
Explanation
One chlorine atom is sufficient to destroy 100,000 ozone molecules in the stratosphere. Chlorine atoms are highly reactive and can catalytically destroy ozone molecules. This process is known as ozone depletion, and it occurs when chlorine atoms react with ozone molecules, breaking them apart. Therefore, even a single chlorine atom can have a significant impact on ozone depletion.
13.
Which of the following refrigerants is a CFC-type refrigerant?
Correct Answer
D. R-12
Explanation
R-12 is a CFC-type refrigerant. CFCs (chlorofluorocarbons) are a type of refrigerant that contains chlorine, fluorine, and carbon atoms. R-12, also known as dichlorodifluoromethane, is a CFC-type refrigerant that was commonly used in air conditioning and refrigeration systems. However, due to its harmful effects on the ozone layer, its production and use have been phased out under the Montreal Protocol.
14.
Which of the following is an example of an HCFC refrigerant?
Correct Answer
C. R-22
Explanation
R-22 is an example of an HCFC refrigerant. HCFC stands for hydrochlorofluorocarbon, which is a type of refrigerant that contains hydrogen, chlorine, fluorine, and carbon atoms. R-22 was commonly used in air conditioning systems and refrigeration equipment, but it is being phased out due to its ozone-depleting properties. It is being replaced by more environmentally friendly alternatives such as R-410A.
15.
Which of the following refrigerants is considered an HFC-type of refrigerant?
Correct Answer
A. R-134a
Explanation
R-134a is considered an HFC-type of refrigerant. HFC stands for hydrofluorocarbon, which is a type of synthetic refrigerant that does not contain chlorine. R-134a is commonly used in automotive air conditioning systems and is known for its low ozone depletion potential. In contrast, R-12, R-22, and R-11 are all types of refrigerants that contain chlorine and are classified as CFCs or HCFCs, which have been phased out due to their harmful effects on the ozone layer.
16.
Which type of refrigerant has the highest Ozone Depletion Potential (ODP)?
Correct Answer
C. CFC
Explanation
CFCs, or chlorofluorocarbons, have the highest Ozone Depletion Potential (ODP) among the given options. CFCs contain chlorine and fluorine atoms, which are released into the atmosphere when they are used as refrigerants. These chemicals can reach the ozone layer and break down ozone molecules, leading to ozone depletion. HFCs (hydrofluorocarbons) and HCFCs (hydrochlorofluorocarbons) also contribute to ozone depletion but to a lesser extent compared to CFCs. Therefore, the correct answer is CFC.
17.
What effect is ozone depletion having on the environment?
Correct Answer
D. All of the above
Explanation
Ozone depletion is having multiple effects on the environment. Firstly, it is leading to increased ground level ozone, also known as smog, which is harmful to human health and can cause respiratory problems. Secondly, it is causing a reduction in marine life, as ozone depletion affects the food chain and disrupts ecosystems. Lastly, it is also reducing crop fields, as the depletion of ozone allows more harmful ultraviolet (UV) radiation to reach the Earth's surface, damaging plants and affecting agricultural productivity. Therefore, all of the given options are correct effects of ozone depletion on the environment.
18.
The abbreviation for refrigerants containing chlorine, fluorine, and carbon is ________.
Correct Answer
C. CFC
Explanation
The correct answer is CFC, which stands for chlorofluorocarbon. Chlorofluorocarbons are a type of refrigerant that contain chlorine, fluorine, and carbon. These compounds were commonly used in refrigeration and air conditioning systems in the past, but they have been phased out due to their harmful effects on the ozone layer.
19.
The abbreviation for refrigerants containing chlorine, fluorine, carbon, and hydrogen is ________.
Correct Answer
B. HCFC
Explanation
HCFC stands for Hydrochlorofluorocarbon, which is the correct abbreviation for refrigerants containing chlorine, fluorine, carbon, and hydrogen. HCFCs are a type of refrigerant that have lower ozone depletion potential compared to CFCs (Chlorofluorocarbons). They are commonly used as alternatives to CFCs in various applications, including air conditioning and refrigeration systems. HCFCs still contribute to global warming, but their impact is less severe compared to CFCs.
20.
The abbreviation for refrigerants containing fluorine, carbon, and hydrogen is ________.
Correct Answer
A. HFC
Explanation
The correct answer is HFC. HFC stands for Hydrofluorocarbon, which is an abbreviation for refrigerants containing fluorine, carbon, and hydrogen. HFCs are commonly used as replacements for chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) due to their lower ozone depletion potential.
21.
To reprocess refrigerant to meet new product specifications is called ________.
Correct Answer
C. Reclaim
Explanation
Reclaiming refrigerant refers to the process of reprocessing it in order to meet new product specifications. This involves removing impurities and contaminants from the refrigerant, ensuring that it can be used again in a safe and efficient manner. The other options, recovery, renew, and recycle, do not specifically imply the reprocessing of refrigerant to meet new specifications, making them incorrect choices.
22.
To clean refrigerant by the use of filter dryers is called
Correct Answer
D. Recycle
Explanation
To clean refrigerant by the use of filter dryers is called recycling. This process involves removing impurities and contaminants from the refrigerant using filter dryers, allowing it to be reused or recharged into the system. Recycling helps to reduce waste and conserve resources by extending the lifespan of the refrigerant and minimizing the need for new refrigerant.
23.
To remove the refrigerant from a system without any testing or processing and to be put back into the same system is called ________.
Correct Answer
A. Recovery
Explanation
Recovery refers to the process of removing refrigerant from a system without any testing or processing, with the intention of putting it back into the same system. This is done to ensure that the refrigerant is safely extracted and reused, without any additional treatment or processing. It is an important step in the overall refrigerant management process to prevent environmental harm and promote sustainability.
24.
Refrigerants that are made up of two refrigerants that, when blended in the right proportions, combine to make a third stable refrigerant, are called ________.
Correct Answer
B. Azeotropes
Explanation
Refrigerants that are made up of two refrigerants that, when blended in the right proportions, combine to make a third stable refrigerant, are called azeotropes. Azeotropes are a type of blend where the components cannot be separated by distillation, as they have the same boiling point and composition as the resulting mixture. This property makes azeotropes ideal for use in refrigeration systems, as they provide stable and consistent performance.
25.
The ozone depletion factor of R-12 is ________.
Correct Answer
D. 1.0
Explanation
The ozone depletion factor of R-12 is 1.0. This means that R-12 has a high potential to deplete the ozone layer. Ozone depletion is a serious environmental issue as it allows harmful ultraviolet (UV) rays from the sun to enter the Earth's atmosphere, which can lead to various health problems and ecological imbalances. Therefore, it is important to minimize the use of substances like R-12 that contribute to ozone depletion.
26.
If a critically charged refrigeration system is over charged, which of the following is a likely result?
Correct Answer
D. Increased operating pressures
Explanation
If a critically charged refrigeration system is overcharged, it is likely to result in increased operating pressures. This is because the system is already charged with the maximum amount of refrigerant it can handle, and any excess refrigerant will cause the pressure inside the system to rise. This can lead to various issues such as strain on the components, potential leaks, and reduced system performance. Therefore, increased operating pressures are a likely result of an overcharged refrigeration system.
27.
Fractionation occurs when ________.
Correct Answer
A. Some of a blended refrigerant evaporates or condenses before the rest of the blend
Explanation
Fractionation occurs when some of a blended refrigerant evaporates or condenses before the rest of the blend. This can happen due to the different boiling points or vapor pressures of the components in the blend. As a result, the composition of the refrigerant mixture may change, leading to a loss of efficiency and potentially causing issues with the system's performance. Additionally, fractionation can also occur when the operating pressures of a system increase, further exacerbating the problem. Therefore, the correct answer is "some of a blended refrigerant evaporates or condenses before the rest of the blend" (option a) and "the operating pressures of a system increase" (option c).
28.
When charging a refrigeration system with a near-azeotropic mixture, what must be done to prevent liquid from entering the system?
Correct Answer
C. Charge as a liquid through the low side using a restrictor.
Explanation
To prevent liquid from entering the system when charging a refrigeration system with a near-azeotropic mixture, it is necessary to charge as a liquid through the low side using a restrictor. This is because a restrictor helps to control the flow of refrigerant and ensures that only the liquid phase enters the system. Charging as a vapor through the high side or charging only liquid through the high side can lead to the entry of unwanted liquid into the system, which can cause damage and affect the system's performance. Charging as a vapor through the low side using a resistor is not a recommended method for preventing liquid entry.
29.
Charging a refrigeration system refers to ________.
Correct Answer
B. Adding refrigerant to a system
Explanation
Charging a refrigeration system refers to adding refrigerant to a system. This is necessary when the refrigerant level in the system is low or when the system has been repaired or maintained. Adding refrigerant helps to maintain the proper operating pressure and temperature in the system, allowing it to effectively cool or freeze the desired space or product.
30.
If 22 oz. of refrigerant are to be added to a refrigeration system and the supply cylinder weighs 24 lb. 12 oz. before any is added, what will be the supply cylinder weight after the system has been charged?
Correct Answer
D. 23 lb. 6 oz
Explanation
24 lb. 12 oz. - 22 oz (1 lb. 6 oz.) = 23 lb. 6 oz.
31.
If 30 oz. of refrigerants are to be added to a refrigeration system and the supply cylinder weighs 26 lb. 4 oz. before any is added, what will the supply cylinder weigh after the system has been charged?
Correct Answer
B. 24 lb. 6 oz.
Explanation
26 lb. 4 oz. (25 lb. 20 oz.) - 30 oz. (1 lb. 14 oz.) = 24 lb. 6 oz.
32.
Refrigerant in liquid form is normally put into a system through the ________.
Correct Answer
A. Liquid line
Explanation
Refrigerant in liquid form is typically added to a system through the liquid line. The liquid line is responsible for carrying the refrigerant from the condenser to the expansion valve. This allows for proper distribution of the refrigerant throughout the system, ensuring efficient cooling. The liquid line is designed to handle the high pressure and temperature of the liquid refrigerant, making it the appropriate choice for adding refrigerant to the system.
33.
Refrigerant in vapor from is normally put into the system through the ________.
Correct Answer
B. Suction line
Explanation
Refrigerant in vapor form is typically introduced into the system through the suction line. This line is responsible for drawing the refrigerant vapor from the evaporator and delivering it to the compressor for compression. The suction line plays a crucial role in the refrigeration cycle by ensuring the continuous flow of refrigerant and maintaining the system's cooling capacity.
34.
When charging a system with vapor refrigerant from a refrigerant cylinder the cylinder will become ________.
Correct Answer
A. Cold
Explanation
When charging a system with vapor refrigerant from a refrigerant cylinder, the refrigerant undergoes a phase change from a high-pressure gas to a low-pressure vapor. This phase change requires the absorption of heat from the surroundings, causing the refrigerant cylinder to become cold. Therefore, the correct answer is "cold".
35.
When charging liquid refrigerant from a single valve supply cylinder, the cylinder is placed ________.
Correct Answer
A. Upside down
Explanation
When charging liquid refrigerant from a single valve supply cylinder, the cylinder is placed upside down. This is because the liquid refrigerant is denser than the gas, and by placing the cylinder upside down, the liquid refrigerant can be easily drawn out through the valve. Placing the cylinder right side up or on its side would make it difficult to extract the liquid refrigerant effectively.
36.
A graduated cylinder charging device is a device that ________.
Correct Answer
D. All of the above
Explanation
A graduated cylinder charging device is a device that can measure refrigerant by volume for precise refrigerant charging. It also has a compensation dial to adjust for the temperature of the refrigerant. Additionally, it often has a heater to prevent the refrigerant temperature from dropping when it is released into the system. Therefore, the correct answer is "all of the above" as all the statements mentioned are true about a graduated cylinder charging device.
37.
The factory charge in a split system, using R-22, shows 6 lb. 8 oz. in the outdoor condensing unit and 2 oz. in the evaporator. The 3/8" liquid line contains 0.48 oz. per foot and the 7/8 " suction line contains 0.10 oz. per foot. The refrigerant lines are 30" long. What is the correct refrigerant charge for this system?
Correct Answer
D. 7 lb. 11 oz.
Explanation
0.48 oz. (liquid line) + 0.10 oz. (suction line) = 0.58 oz
0.58 x 30 (refrigerant length) = 17.4 oz
6 lb. 8 oz. + 2 oz. + 17.4 oz. = 6 lb. 27.4 oz OR 7 lb. 11.4 oz.
38.
After repairing a system that has had an electrical motor failure (compressor burnout), it is a good field practice to re-use the recovered refrigerant in that system.
Correct Answer
B. False
Explanation
It is not a good field practice to re-use the recovered refrigerant in a system after repairing it following an electrical motor failure (compressor burnout). This is because the refrigerant may have been contaminated during the motor failure, and reusing it can lead to further issues and potential damage to the system. It is recommended to properly dispose of the recovered refrigerant and use new, clean refrigerant when repairing the system.
39.
Air entering a refrigerant system can eventually lead to compressor failure.
Correct Answer
A. True
Explanation
Air entering a refrigerant system can lead to compressor failure because air contains moisture and contaminants that can cause corrosion and damage to the compressor components. When the air mixes with the refrigerant, it forms acids that can eat away at the compressor's internal parts. Additionally, air can cause the formation of ice inside the system, leading to blockages and reduced efficiency. Therefore, it is crucial to prevent air from entering the refrigerant system to ensure the proper functioning and longevity of the compressor.
40.
Clearance tolerances are such that the ordinary clean refrigerant oil can be used satisfactorily in a vacuum pump.
Correct Answer
B. False
Explanation
The statement suggests that ordinary clean refrigerant oil can be used satisfactorily in a vacuum pump given the clearance tolerances. However, this is not true. Vacuum pumps require specific types of oil that are designed to withstand the conditions and pressures within the pump. Using ordinary clean refrigerant oil can lead to inefficiency and potential damage to the pump.
41.
While under a deep vacuum, any liquid water under the oil in the motor-compressor assembly can be removed by operating the compressor motor for several seconds without any adverse effect on the system.
Correct Answer
B. False
Explanation
Operating the compressor motor for several seconds while under a deep vacuum will not remove any liquid water under the oil in the motor-compressor assembly. This is because the deep vacuum creates a low-pressure environment, causing the water to boil and turn into vapor. The vapor will mix with the oil, making it difficult to remove. Therefore, operating the compressor motor in this situation will not have any effect on removing the liquid water.
42.
The maximum recommended pressure for leak testing is 150 psig.
Correct Answer
A. True
Explanation
The maximum recommended pressure for leak testing is 150 psig. This means that it is advised to not exceed this pressure when conducting leak tests. Going above this pressure could potentially cause damage or lead to inaccurate results. Therefore, it is important to adhere to this recommendation to ensure safe and effective leak testing.
43.
The oil in a vacuum pump should be changed after each time it is used.
Correct Answer
A. True
Explanation
The oil in a vacuum pump should be changed after each use because it can become contaminated with moisture, dust, and other particles during the pumping process. Regularly changing the oil helps to maintain the efficiency and performance of the pump, ensuring that it continues to operate effectively. Failure to change the oil regularly can lead to decreased vacuum levels, reduced pump performance, and potential damage to the pump components. Therefore, it is important to change the oil after each use to maintain the pump's functionality.
44.
It is possible to have a leak-free system when under a vacuum but still leak when the system pressure is above atmospheric.
Correct Answer
A. True
Explanation
In a vacuum, the pressure inside the system is lower than atmospheric pressure, which creates a pressure differential that helps to keep the system sealed and prevents leaks. However, when the system pressure is above atmospheric, there is no pressure differential to keep the system sealed, and leaks can occur. Therefore, it is possible to have a leak-free system under a vacuum but still experience leaks when the system pressure is above atmospheric.
45.
Refrigerants that have a low Ozone Depletion Potential (ODP) will, in turn, have a high "Total Equivalent Warming Impact" (TEWI).
Correct Answer
B. False
Explanation
Refrigerants that have a low Ozone Depletion Potential (ODP) will not necessarily have a high "Total Equivalent Warming Impact" (TEWI). The ODP refers to the potential of a substance to deplete the ozone layer, while the TEWI measures the overall warming impact of a substance, taking into account both its direct and indirect contributions to global warming. Therefore, it is possible for a refrigerant to have a low ODP and a low TEWI, indicating that it has a minimal impact on both the ozone layer and global warming.
46.
The DOT-approved cylinder used for recovering refrigerant is gray and yellow.
Correct Answer
A. True
Explanation
The DOT-approved cylinder used for recovering refrigerant is gray and yellow because these colors are specifically designated for this purpose. The gray color indicates that the cylinder is designed for hazardous materials, while the yellow color signifies that it is meant for refrigerants. This color coding system helps to ensure that the correct cylinders are used for handling and storing different types of substances, promoting safety and compliance with regulations.
47.
A refrigerant reclaimed from a system may be charged back into the system from which it came.
Correct Answer
A. True
Explanation
When a refrigerant is reclaimed from a system, it means that it has been properly cleaned, purified, and restored to its original condition. Therefore, it is safe and suitable to be charged back into the same system from which it was removed. This process helps to reduce waste and minimize the need for new refrigerants, making it an environmentally friendly practice.
48.
Mechanical refrigerant recovery equipment must meet specification established by the 1993 ARI 740 standard.
Correct Answer
A. True
Explanation
The statement is true because mechanical refrigerant recovery equipment needs to meet the specifications set by the 1993 ARI 740 standard. This standard ensures that the equipment is designed and built to effectively recover refrigerants, which is important for environmental and safety reasons. Compliance with this standard ensures that the equipment is efficient, reliable, and meets industry standards.
49.
When technicians works for a company in which the technician does not have a financial interest, the technician does not have to be certified.
Correct Answer
B. False
Explanation
Certification is a separate requirement from financial interest. Even if a technician does not have a financial interest in the company they work for, they still need to be certified in order to perform their job duties effectively and ensure the quality of their work. Therefore, the statement that the technician does not have to be certified is false.
50.
Glide is the range of temperatures/pressures in which a blended refrigerant will condense.
Correct Answer
A. True
Explanation
The statement is true because glide refers to the temperature or pressure range over which a blended refrigerant will condense. This means that the refrigerant mixture will not condense at a single temperature or pressure, but rather over a range. Therefore, the statement is correct.