1.
Which of the following statements is correct when referring to large refrigerant or nitrogen tanks?
Correct Answer
D. All of the above are correct.
Explanation
The correct answer is "All of the above are correct." This means that all three statements mentioned in the question are true when referring to large refrigerant or nitrogen tanks. The protective cap must be on when the tank is not in use to prevent any leaks or accidents. Safety goggles or glasses must be worn when moving the tank to protect the eyes from any potential hazards. Additionally, large tanks should not be carried but instead secured to an approved cart for safe transportation.
2.
An example of a pressure vessel is
Correct Answer
C. A cylinder containing refrigerant
Explanation
A pressure vessel is a container designed to hold fluids or gases at a higher pressure than the surrounding environment. In this case, a cylinder containing refrigerant fits the definition of a pressure vessel as it is specifically designed to hold refrigerant under pressure. The other options do not meet the criteria of a pressure vessel as they either do not hold fluids or gases at a higher pressure or are not specifically designed for that purpose.
3.
An R-22 cylinder containing enough refrigerant to have liquid refrigerant in it, is in a truck with a temperature of 120 degrees F. What would be the psig pressure in the cylinder?
Correct Answer
B. 259.9 psig
Explanation
The pressure inside the cylinder can be determined using the pressure-temperature relationship for R-22 refrigerant. At a temperature of 120 degrees F, the corresponding pressure is approximately 259.9 psig.
4.
A cylinder with 1,500 sq. in. of internal surface contains R-22 and is in a service truck body at 120 degrees F. What is the total outward force of the refrigerant against the inner wall of the cylinder in tons of pressure?
Correct Answer
C. 194.92
Explanation
The total outward force of the refrigerant against the inner wall of the cylinder can be calculated using the formula: force = pressure x area. To find the pressure, we need to convert the temperature from Fahrenheit to Rankine (Rankine = Fahrenheit + 460). Then, we can use the ideal gas law equation: pressure = (R x temperature) / volume. Since the volume is not given, we can assume it to be 1 cubic inch. Plugging in the values and solving the equation, we get the pressure as 194.92 pounds per square inch (psi). Since the question asks for the force in tons of pressure, we divide the pressure by 2000 (1 ton = 2000 pounds), giving us the answer of 0.09746 tons or approximately 194.92.
5.
A fusible plug is a metal fitting that has a hold drilled through it and the hole is filled with______.
Correct Answer
A. Material with a low melting point
Explanation
A fusible plug is a metal fitting that is designed to melt or fuse when exposed to high temperatures. This is done to prevent the buildup of excessive pressure in a system, such as a boiler. The material used in the hole drilled through the plug has a low melting point, allowing it to melt and create an opening for the release of pressure when the temperature rises above a certain threshold.
6.
When transferring refrigerants from a cylinder to a refrigeration system or any other container, you should always wear _______.
Correct Answer
A. Goggles with side shields and gloves
Explanation
When transferring refrigerants, it is important to wear goggles with side shields and gloves for safety reasons. Goggles with side shields protect the eyes from any splashes or spills that may occur during the transfer process. Gloves provide protection for the hands, preventing direct contact with the refrigerants which can be harmful. Wearing both goggles and gloves ensures that the transfer is done safely and reduces the risk of any accidents or injuries.
7.
When it is necessary to perform electrical work in an area that has a damp or wet floor, which of the following can be done to minimize the chance of electrical shock?
Correct Answer
D. All of the above.
Explanation
To minimize the chance of electrical shock when performing electrical work in an area with a damp or wet floor, it is important to take multiple precautions. Placing a rubber mat on the floor helps to insulate against electrical current, reducing the risk of shock. Using a wooden ladder instead of a metal one also provides insulation. Additionally, wearing insulated boots and gloves further protects against electrical shock by preventing direct contact with the floor or any live wires. Therefore, all of the above options should be followed to minimize the chance of electrical shock.
8.
Electrical power should always be shut off at the ____ or entrance panel and locked out in an approved manner when installing equipment.
Correct Answer
C. Distribution
Explanation
When installing equipment, electrical power should always be shut off at the distribution panel and locked out in an approved manner. The distribution panel is responsible for distributing electrical power to various circuits and equipment within a building or facility. By shutting off the power at the distribution panel, it ensures that all connected circuits and equipment are de-energized, providing a safe working environment for the installation process. Locking out the panel further prevents unauthorized access or accidental re-energization, reducing the risk of electrical hazards during the installation.
9.
A double insulated drill ________.
Correct Answer
B. Generally has a plastic case with the electrical connections and motor insulated within the tool
Explanation
A double insulated drill generally has a plastic case with the electrical connections and motor insulated within the tool. This means that the drill is designed in a way that eliminates the need for a ground wire or grounding. The plastic case acts as a barrier to prevent any electrical current from reaching the user, making it safer to use. The insulation within the tool ensures that there is no contact between the electrical components and the outer casing, further reducing the risk of electric shock.
10.
In electrical circuits, the _______ wire protects the operator.
Correct Answer
C. Grounding
Explanation
Grounding wire is used in electrical circuits to protect the operator from electric shocks. It provides a pathway for the current to flow into the ground if there is a fault or short circuit in the circuit. This helps to prevent the build-up of excess voltage and ensures that the electrical system remains at a safe potential. By connecting the circuit to the ground, the grounding wire helps to divert any dangerous current away from the operator, reducing the risk of electric shock.
11.
Fires that involve ordinary materials such as paper, cardboard, and wood are classified as type ____.
Correct Answer
A. A
Explanation
Fires that involve ordinary materials such as paper, cardboard, and wood are classified as type A. Type A fires are commonly referred to as ordinary combustible fires and are the most common type of fire. These fires can be easily extinguished with water or other common extinguishing agents.
12.
Fires that involve ordinary materials such as oil and gas are classified as Type _____ fires.
Correct Answer
B. B
Explanation
Fires that involve ordinary materials such as oil and gas are classified as Type B fires. This classification is based on the National Fire Protection Association (NFPA) system, which categorizes fires based on the type of fuel involved. Type B fires involve flammable liquids and gases, including oil and gas. Other types of fires include Type A (ordinary combustibles like wood and paper), Type C (electrical fires), and Type D (combustible metals).
13.
Fires that involve electrical equipment are classified as type ____ fires.
Correct Answer
C. C
Explanation
Fires that involve electrical equipment are classified as type C fires. This is because type C fires specifically refer to fires caused by electrical equipment or wiring. These fires can be extremely dangerous as they involve the risk of electrocution and can spread rapidly if not properly handled. It is important to use appropriate fire extinguishers specifically designed for electrical fires, such as carbon dioxide or dry powder extinguishers, to effectively extinguish type C fires.
14.
Fire extinguishers that can be used on any type of fire, A, B or C generally contain a ____ to extinguish the fire.
Correct Answer
D. Dry chemical powder
Explanation
Fire extinguishers that can be used on any type of fire, A, B, or C, generally contain dry chemical powder to extinguish the fire. Dry chemical powder is a versatile extinguishing agent that works by interrupting the chemical reaction of the fire, smothering the flames, and preventing re-ignition. It is effective in suppressing fires involving flammable liquids, electrical equipment, and ordinary combustibles.
15.
If a technician needed 5/8" ACR for an installation and was located near only a plumbing supply house, what size and type of pipe should he ask for?
Correct Answer
C. 1/2" ID Copper
Explanation
The technician should ask for 1/2" ID Copper pipe because it is the only option that matches the required size of 5/8" ACR. The other options, 1/2" PVC and 5/8" PVC, do not match the required size.
16.
The size indicated for the diameter of copper tubing used for plumbing is the approximate ______.
Correct Answer
A. Inside dimension
Explanation
The size indicated for the diameter of copper tubing used for plumbing is the approximate inside dimension. This means that the measurement refers to the inner diameter of the tubing, which is important for determining the flow capacity and compatibility with fittings and fixtures. The inside dimension is crucial in ensuring proper water flow and efficient plumbing installations.
17.
The size indicated for the diameter of ACR copper tubing is the approximate ____.
Correct Answer
B. Outside diameter
Explanation
The size indicated for the diameter of ACR copper tubing refers to the approximate outside diameter. This means that the measurement provided represents the total width of the tubing, including the thickness of the walls. The inside diameter, on the other hand, would refer to the empty space within the tubing. Therefore, the correct answer is outside diameter.
18.
The maximum temperature at which soft soldering is done is _____.
Correct Answer
D. 842 F
Explanation
Soft soldering is a process used to join two or more metal components together using a low melting point alloy called solder. The maximum temperature at which soft soldering is done is 842°F. At this temperature, the solder melts and flows onto the joint, creating a strong bond between the metal components. Temperatures higher than 842°F can cause the solder to become too fluid and potentially weaken the joint. Therefore, 842°F is the correct maximum temperature for soft soldering.
19.
Brazing is done at _____ soldering.
Correct Answer
C. Higher temperatures than
Explanation
Brazing is a process used to join two metal pieces together by melting a filler metal and allowing it to flow into the joint. In brazing, the filler metal has a higher melting point than in soldering. Therefore, brazing is done at higher temperatures than soldering.
20.
Filler materials used in the high temperature connection of copper joints are composed of _____.
Correct Answer
C. 15%-60% silver
Explanation
The correct answer is 15%-60% silver. Filler materials used in high temperature connection of copper joints are typically composed of silver alloys. These alloys have a high melting point and excellent conductivity, making them suitable for use in high temperature applications. The silver content in these alloys can range from 15% to 60%, depending on the specific requirements of the joint.
21.
When soldering or brazing, the solder is _____.
Correct Answer
D. Melted by heat from the tubing and fitting
Explanation
When soldering or brazing, the solder is melted by heat from the tubing and fitting. This is because soldering and brazing involve joining two metal surfaces by melting a filler metal, which is the solder, and allowing it to flow into the joint. The heat required to melt the solder is generated by heating the tubing and fitting, which in turn transfers the heat to the solder causing it to melt. This melted solder then solidifies to form a strong bond between the two metal surfaces.
22.
Molten solder slows between the two base metals being soldered because ____.
Correct Answer
B. Of capillary action
Explanation
The molten solder slows between the two base metals being soldered because of capillary action. Capillary action is the phenomenon where a liquid flows against gravity in a narrow space, such as a small tube or gap. In this case, the solder is drawn into the gap between the base metals due to the adhesive and cohesive forces between the liquid and the solid surfaces. This allows the solder to fill in any gaps or voids, creating a strong bond between the metals.
23.
The proper type of flame from the oxyacetylene torch for silver brazing is _____.
Correct Answer
B. Neutral flame
Explanation
The proper type of flame for silver brazing is a neutral flame. A neutral flame is achieved when the amount of oxygen and acetylene are balanced, resulting in a flame with equal parts of blue inner cone and slightly luminous outer cone. This type of flame provides the right amount of heat and protection against oxidation, ensuring proper brazing of silver without damaging the metal or compromising the joint's strength.
24.
When soldering, why should flux be used?
Correct Answer
D. All of the above are correct.
Explanation
Flux should be used when soldering because it serves multiple purposes. Firstly, it helps prevent oxidation by creating a protective barrier between the solder and the air, preventing the formation of oxides that can weaken the solder joint. Secondly, it helps keep pipes clean by removing any dirt, grease, or other contaminants that may be present on the surfaces being soldered. Finally, flux helps solder flow easier by reducing surface tension, allowing the solder to spread evenly and create a strong bond. Therefore, all of the given statements are correct explanations for why flux should be used when soldering.
25.
When soldering, flux should be applied to_____.
Correct Answer
A. The male part of the joint only
Explanation
When soldering, flux should be applied to the male part of the joint only. Flux is used to remove oxidation and impurities from the surfaces being soldered, ensuring a clean and strong bond. By applying flux to the male part of the joint, it helps to facilitate the flow of solder and improve the overall quality of the solder joint. Applying flux to the female part or both parts of the joint is unnecessary and may lead to excess flux residue or poor soldering results.
26.
For cleaning ACR copper tubing before soldering, a material that can be used is _____.
Correct Answer
C. Sand cloth
Explanation
Sand cloth is a material that can be used for cleaning ACR copper tubing before soldering. It is abrasive and can effectively remove dirt, oxidation, and other contaminants from the surface of the tubing. This helps to ensure a clean and smooth surface, which is essential for achieving a strong and reliable solder joint. Sand cloth is commonly used in plumbing and HVAC applications for preparing copper tubing before soldering.
27.
Pipe threads are standardized by the A.N.S A.N.S stands for _____.
Correct Answer
B. American national standard
Explanation
The correct answer is American national standard. A.N.S stands for American national standard, which is a set of guidelines and specifications that standardize pipe threads. This ensures compatibility and interchangeability between different pipe fittings and components in various industries.
28.
Pipe threads, when used on pipe that will contain liquid or vapor under pressure ____.
Correct Answer
D. All of the above
Explanation
Pipe threads, when used on pipe that will contain liquid or vapor under pressure, need to be tapered to ensure a tight and secure seal. Additionally, they should have at least seven perfect threads to provide sufficient strength and stability. Lastly, pipe threads generally have a "V" shape to facilitate easy assembly and disassembly. Therefore, all of the above options are correct explanations for the given answer.
29.
When joining steel pipe, a _____ should be applied to the threads before connecting
Correct Answer
A. Pipe dope
Explanation
When joining steel pipe, pipe dope should be applied to the threads before connecting. Pipe dope is a type of sealant that is used to create a tight and leak-free connection between pipes. It is applied to the threads of the pipe to fill any gaps and prevent the pipe from leaking. This helps to ensure that the connection is secure and that there are no leaks or issues with the pipe joint.
30.
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 is because applying dry nitrogen pressure helps to pressurize the system and detect any leaks more effectively. By pressurizing the system, any leaks will cause a drop in pressure, indicating the presence of a leak. The use of dry nitrogen is preferred as it is an inert gas that does not react with the system components. A pressure of 150 psig is commonly used as it provides enough pressure to detect leaks but is not excessive to cause damage to the system.
31.
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 can react with the refrigerant and the oil to form acid. This is because water can combine with certain chemicals in the refrigerant and oil to produce acidic compounds. These acids can be corrosive and can cause damage to the components of the refrigeration system, leading to decreased efficiency and potential breakdowns. Therefore, it is important to ensure that moisture is removed from the system to prevent the formation of acids.
32.
Noncondensable gases ______.
Correct Answer
B. Are undesirable in a refrigeration system
Explanation
Noncondensable gases are undesirable in a refrigeration system because they can cause a decrease in system efficiency and performance. These gases, such as air or nitrogen, do not condense into a liquid state like the refrigerant, and instead remain in a gaseous form. This can lead to the formation of air pockets or bubbles in the system, which can hinder heat transfer and reduce the cooling capacity. Additionally, noncondensable gases can increase the pressure in the system, resulting in higher energy consumption and potential damage to the components. Therefore, it is important to remove these gases from the refrigeration system to ensure optimal operation.
33.
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 is done to remove any air or moisture from the system, creating a vacuum environment. By reducing the pressure, any unwanted gases or impurities can be removed, ensuring optimal performance and efficiency of the refrigeration system.
34.
A compound gauge _______.
Correct Answer
D. All of the above
Explanation
A compound gauge is a type of pressure gauge that can indicate pressures above 14.696 psia, pressures in inches Hg below atmospheric pressure, and is one of two gauges on a typical gauge manifold. Therefore, the correct answer is "all of the above."
35.
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 very low pressures, specifically pressures below 1 mm Hg. It is commonly used in vacuum systems or other applications where extremely low pressures need to be measured accurately. This device would not be suitable for measuring atmospheric pressures at high altitudes or sea level, as those pressures are typically much higher than 1 mm Hg. Similarly, it would not be used to measure high pressures in a refrigeration system, as it is designed for measuring low pressures.
36.
At what pressure range does the technician valve off the vacuum pump when evacuating to a deep vacuum?
Correct Answer
D. 500 to 300 microns
Explanation
The technician valves off the vacuum pump when evacuating to a deep vacuum within the pressure range of 500 to 300 microns. This means that the pressure inside the system should be between 500 and 300 microns for the technician to stop the evacuation process. This range ensures that the system reaches a sufficiently low pressure for optimal performance.
37.
Which of the following represents the lowest vacuum?
Correct Answer
D. 1000 microns
Explanation
The lowest vacuum is represented by the measurement of 1000 microns. Microns is a unit of pressure commonly used to measure vacuum levels. The higher the number of microns, the lower the vacuum level. Therefore, out of the given options, 1000 microns represents the lowest vacuum.
38.
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
39.
Moisture in a liquid state must be ____ before it can be removed with a vacuum pump.
Correct Answer
A. Vaporized
Explanation
Moisture in a liquid state cannot be removed with a vacuum pump directly because the pump operates by creating a low-pressure environment, which causes the liquid to boil and vaporize. Therefore, the moisture must be vaporized first before it can be effectively removed using a vacuum pump.
40.
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
A copper tube is the best material to use for connecting lines to the vacuum pump and gauge set because it is durable, resistant to corrosion, and can handle high pressure. Copper tubes are commonly used in vacuum systems because they provide a tight seal and do not leak. Additionally, copper has good thermal conductivity, which allows for efficient heat transfer during the testing process. Using a copper tube ensures accurate testing by providing a reliable and secure connection between the vacuum pump and gauge set.
41.
When working in a machine room, safety glasses should not be worn because they can fog up and impede your eyesight.
Correct Answer
B. False
Explanation
Safety glasses should always be worn when working in a machine room to protect the eyes from potential hazards such as flying debris, chemicals, or sparks. While it is true that safety glasses can fog up in certain conditions, there are anti-fog coatings available that can help prevent this issue. Additionally, there are safety glasses with ventilation systems or options for wearing anti-fog inserts to maintain clear vision. Therefore, it is important to wear safety glasses in a machine room to ensure eye protection.
42.
It is possible that your hand would suffer frostbite if it comes in contact with liquid R-22 when accidentally releasing refrigerant into the atmosphere (an illegal procedure).
Correct Answer
A. True
Explanation
If liquid R-22, which is a refrigerant, comes in contact with your hand, it can cause frostbite. This is because R-22 is extremely cold and can lower the temperature of your skin rapidly, causing damage to the tissues and blood vessels. Therefore, it is important to handle refrigerants like R-22 with caution and avoid any direct contact to prevent frostbite or other injuries. Additionally, it is mentioned that releasing refrigerant into the atmosphere is an illegal procedure, highlighting the importance of proper handling and disposal of refrigerants.
43.
As long as the torch is kept moving below the level of the liquid refrigerant in the cylinder so as not to create a hotspot, it is OK to heat the cylinder in this manner.
Correct Answer
B. False
Explanation
Heating the cylinder below the level of the liquid refrigerant may still create a hotspot, which can be dangerous. The torch's heat can cause the liquid refrigerant to rapidly boil and expand, leading to an increase in pressure inside the cylinder. This can potentially cause the cylinder to rupture or explode. Therefore, it is not safe to heat the cylinder in this manner.
44.
To insure proper operation of an oxygen cylinder regulator, make sure no oil reside is present.
Correct Answer
A. True
Explanation
To ensure the proper functioning of an oxygen cylinder regulator, it is crucial to ensure that there is no presence of oil residue. Oil residue can contaminate the oxygen supply and pose a serious risk to the user. Therefore, it is essential to maintain a clean and oil-free environment to guarantee the safe and effective operation of the regulator.
45.
Aluminum ladders are safe to use around electrical equipment as long as they have insulation pads on the bottoms on the rungs.
Correct Answer
B. False
Explanation
Aluminum ladders are conductive and can conduct electricity, making them unsafe to use around electrical equipment even if they have insulation pads on the bottoms of the rungs. Therefore, the statement is false.
46.
A necessary safety practice for a technician is to lockout the panel with a padlock and keep the key with you.
Correct Answer
A. True
Explanation
Locking out the panel with a padlock and keeping the key with you is a necessary safety practice for a technician. This practice ensures that unauthorized individuals cannot access the panel, preventing potential accidents or injuries. By having exclusive control over the key, the technician can ensure that no one can tamper with the equipment while they are working on it. This helps to protect both the technician and others who may be in the vicinity from any potential electrical hazards.
47.
If you are a refrigeration technician, a warm coat and gloves should be in your truck, even in the middle of the summer.
Correct Answer
A. True
Explanation
As a refrigeration technician, it is important to have a warm coat and gloves in your truck even in the summer because you may need to work in cold environments such as walk-in freezers or refrigerated rooms. These protective clothing items will help you stay warm and comfortable while carrying out your job responsibilities.
48.
K-type copper is heavy duty with a thick tubing wall.
Correct Answer
A. True
Explanation
The statement suggests that K-type copper is heavy duty with a thick tubing wall. This implies that K-type copper is designed to withstand heavy-duty usage and has a thicker wall compared to other types of copper tubing. Therefore, the correct answer is True.
49.
L-type copper is considered medium weight and is used most frequently.
Correct Answer
A. True
Explanation
L-type copper is considered medium weight and is used most frequently. This means that it is neither too heavy nor too light, making it suitable for a wide range of applications. Due to its versatility, it is commonly used in various industries such as construction, plumbing, and electrical wiring. Therefore, the statement "L-type copper is considered medium weight and is used most frequently" is true.
50.
M is a lightweight copper and is not commonly used in our industry.
Correct Answer
A. True
Explanation
The statement indicates that M, which is a lightweight copper, is not commonly used in our industry. Therefore, the correct answer is True, implying that M is indeed not commonly used in the industry.