1.
A manifold gauge set can be used during the evacuation of the A/C system.
Correct Answer
A. True
Explanation
A manifold gauge set is a tool used to measure the pressure and temperature of the refrigerant in an air conditioning system. During the evacuation process, the manifold gauge set is connected to the A/C system to monitor the pressure levels and ensure that the system is being properly evacuated. This is important because a proper evacuation removes any air or moisture from the system, which can cause damage or reduce the efficiency of the A/C system. Therefore, using a manifold gauge set during the evacuation process is necessary to ensure the A/C system is properly evacuated.
2.
A manifold gauge set can be used during A/C system diagnosis.
Correct Answer
A. True
Explanation
A manifold gauge set is a tool used to measure and monitor pressure in an air conditioning system. It consists of multiple gauges that provide readings for both high and low pressure sides of the system. By connecting the gauge set to the A/C system, technicians can diagnose issues such as low refrigerant levels, blockages, or compressor problems. The readings obtained from the gauge set help in determining the overall health and performance of the system, making it an essential tool for A/C system diagnosis.
3.
Refrigerant condenses quickly when exposed to the atmosphere.
Correct Answer
B. False
Explanation
Refrigerant does not condense quickly when exposed to the atmosphere. In fact, refrigerant is designed to remain in a gaseous state at normal atmospheric conditions. It only condenses when it is inside a closed system and subjected to low temperatures and high pressure.
4.
A manifold gauge set is used to determine both high-side and low-side pressures in the refrigeration system.
Correct Answer
A. True
Explanation
A manifold gauge set is a tool that is commonly used by HVAC technicians to measure both the high-side and low-side pressures in a refrigeration system. This allows them to assess the performance and efficiency of the system, as well as diagnose any potential issues. By connecting the gauge set to the system, the technician can obtain accurate readings of the pressure levels on both sides, providing valuable information for troubleshooting and maintenance purposes. Therefore, the statement that a manifold gauge set is used to determine both high-side and low-side pressures in the refrigeration system is true.
5.
Warm underhood temperatures produce lower than normal A/C system pressures.
Correct Answer
B. False
Explanation
Warm underhood temperatures do not produce lower than normal A/C system pressures. In fact, warm temperatures typically lead to higher A/C system pressures. This is because the refrigerant in the A/C system expands and becomes more pressurized when exposed to heat. Therefore, the correct answer is False.
6.
A single drop of water in an A/C refrigeration sytsem may cause damage to the system.
Correct Answer
A. True
Explanation
Water in an A/C refrigeration system can cause damage because water can freeze and block the flow of refrigerant, leading to system malfunction. Additionally, water can cause corrosion and rusting of metal components, which can further impair the system's functionality. Therefore, even a single drop of water in the system can potentially cause significant damage.
7.
Refrigerant is lighter than oxygen.
Correct Answer
B. False
Explanation
Refrigerant is not necessarily lighter than oxygen. The density of a refrigerant can vary depending on its specific composition and properties. While some refrigerants may be lighter than oxygen, others may be heavier or have similar densities. Therefore, it cannot be generalized that all refrigerants are lighter than oxygen, making the statement false.
8.
R-12 is stored in light blue containers.
Correct Answer
B. False
Explanation
The given statement is false because R-12 is not stored in light blue containers.
9.
R-134a is stored in yellow containers.
Correct Answer
B. False
Explanation
The given statement is false because R-134a, a type of refrigerant, is typically stored in containers that are color-coded as light blue, not yellow. The color coding helps to easily identify the type of refrigerant contained in the containers and ensures proper handling and usage.
10.
Which of the following statements best defines the term 'evacuation'?
Correct Answer
C. Evacuation is a process that removes all traces of air, moisture, and refrigerant from the system.
Explanation
Evacuation is a process that removes all traces of air, moisture, and refrigerant from the system. This definition accurately describes the purpose and outcome of an evacuation process. It emphasizes the removal of not only air and moisture but also refrigerant, which is crucial for maintaining the efficiency and performance of the system. By eliminating these elements, the system can operate effectively and prevent any potential damage or malfunctions.
11.
Which of the following statements is not true about orifice tube systems?
Correct Answer
B. The liquid line from the condenser outlet to the orifice tube should be cool.
Explanation
The correct answer is that the liquid line from the condenser outlet to the orifice tube should be cool. In an orifice tube system, the liquid line carries refrigerant in its liquid state from the condenser to the orifice tube. The purpose of the orifice tube is to regulate the flow of refrigerant into the evaporator. The liquid line should actually be warm, as it carries high-pressure, high-temperature refrigerant from the condenser to the orifice tube. Once the refrigerant passes through the orifice tube, it undergoes a pressure drop and becomes a cool, low-pressure liquid, which then enters the evaporator.
12.
Which of the following cannot cause excessive heat?
Correct Answer
C. A water flow control valve not opening fully
Explanation
A water flow control valve not opening fully cannot cause excessive heat because if the valve is not opening fully, it means that the flow of water is restricted or limited. This would result in less water reaching the heater or radiator, causing a decrease in heat rather than excessive heat.
13.
To charge an air conditioning system while it is running, the refrigerant should be added to the:
Correct Answer
B. Low side
Explanation
To charge an air conditioning system while it is running, the refrigerant should be added to the low side. The low side of the system is where the refrigerant enters the compressor, which then compresses and sends it to the high side. Adding refrigerant to the low side ensures that it is properly circulated through the system and can effectively cool the air. Adding refrigerant to the high side could cause damage to the system and is not recommended. Therefore, the correct answer is the low side.
14.
R-12 refrigerant exposed to an open flame will produce:
Correct Answer
D. pHosgene gas
Explanation
When R-12 refrigerant is exposed to an open flame, it will produce phosgene gas. Phosgene gas is a highly toxic substance that was used as a chemical weapon during World War I. It is formed when chlorofluorocarbons (CFCs) are exposed to high temperatures, such as those produced by an open flame. Inhaling phosgene gas can cause severe respiratory distress and even death. Therefore, it is important to handle refrigerants like R-12 with caution and avoid exposing them to flames or high temperatures.
15.
R-12 and R-134a:
Correct Answer
A. Should never be mixed
Explanation
R-12 and R-134a should never be mixed because they are different types of refrigerants with different chemical properties. Mixing them can lead to system damage, reduced cooling efficiency, and potential safety hazards. It is important to use the correct refrigerant for a specific system and not mix different types.
16.
EPA certification is required to:
Correct Answer
C. Both A and B
Explanation
EPA certification is required to both service R-12 A/C systems and purchase R-12. This means that individuals must have the necessary certification in order to perform maintenance or repairs on R-12 A/C systems and also to buy R-12 refrigerant. The certification ensures that individuals have the knowledge and skills necessary to handle these tasks safely and in compliance with environmental regulations.
17.
Technician A says evacuating (pumping down) an air conditioning system removes air and moisture from the system. Tcehnician B says evacuating (pumping down) an air conditioning sytem removes dirt particles from the system. Who is correct?
Correct Answer
A. A only
Explanation
Evacuating an air conditioning system involves removing air and moisture from the system. This process is typically done using a vacuum pump, which creates a vacuum and pulls out any air and moisture present in the system. However, evacuating the system does not remove dirt particles. Therefore, Technician A is correct in stating that evacuating an air conditioning system removes air and moisture, while Technician B is incorrect in claiming that it also removes dirt particles.