Refrigeration & AC - Assistant

The correct answer is B) X. The high-pressure cutout, which is a safety device that shuts off the fuel supply to the engine when the fuel pressure becomes too high, is indicated by the component labeled X in the illustration GS-RA-12. The other options, A) W, C) Y, and D) Z, represent different components of the fuel system or engine, but do not specifically indicate the high-pressure cutout. This knowledge is based on the typical design and components of marine engine fuel systems, which is a key part of the US Coast Guard Captain's License Examinations.

The correct answer is D) 80 degrees F. To determine the wet bulb temperature, we need to use the dry bulb temperature (90 degrees F) and the relative humidity (65%) provided in the question. By using a psychrometric chart or a wet bulb temperature calculator, the wet bulb temperature can be determined to be 80 degrees F for the given conditions. The other options are incorrect because they do not accurately reflect the wet bulb temperature for the given dry bulb temperature and relative humidity. Option A (62 degrees F) and Option B (63 degrees F) are too low, while Option C (77 degrees F) is too low compared to the correct answer of 80 degrees F.

The correct answer is B. Heat is removed from the refrigerant circulating through the refrigeration system by the condenser, which is component B in the illustration GS-RA-12. The condenser is responsible for removing heat from the high-pressure, high-temperature refrigerant vapor coming from the compressor and transferring that heat to the surrounding air or cooling water, causing the refrigerant to condense into a high-pressure liquid. The other options are incorrect because component A is the compressor, component J is the expansion valve, and component K is the evaporator. None of these components are responsible for removing heat from the refrigerant in this refrigeration system.

The correct answer is D) The valve will fail closed, providing no cooling capacity. When the power element of the thermostatic expansion valve loses its charge, the valve spring will cause the valve to close, shutting off the flow of refrigerant to the evaporator. This will result in a complete loss of cooling capacity, as the valve will fail in the closed position and prevent any refrigerant from reaching the evaporator. The other options are incorrect because: A) the valve will not fail open, as it is designed to close without pressure in the power element; B) the external equalizing line cannot keep the valve unseated if the power element is uncharged; and C) the valve is not designed to fail open to provide continuous cooling when the power element is lost.

The correct answer is D) The expansion valve would hunt excessively, alternately starving and overfeeding the evaporator coil. This is because an oversized valve cage assembly (5 tons) compared to the original (1/2 ton) would cause the expansion valve to be unable to properly regulate the flow of refrigerant to the evaporator. The excessive capacity of the replacement valve would cause it to alternate between starving and overfeeding the evaporator, leading to inconsistent superheat levels and the expansion valve "hunting" - rapidly adjusting in an attempt to maintain proper superheat. This would result in unstable operation and potential equipment damage over time. The other answer choices are incorrect because: A) the evaporator would not be consistently underfeeding, and B) the expansion valve would not function normally with such a mismatch in capacity. C) is also incorrect, as the evaporator would not consistently overheat but rather experience fluctuating superheat levels.

The correct answer is D. The illustration GS-RA-69 shows a hermetic service valve, which is used to gain access to a hermetic (sealed) system. This type of valve features a Schrader core valve that is unseated by the core depressor of a hose fitting when it is attached. This allows access to the sealed system for service or maintenance. The other options, A, B, and C, do not match the description of a hermetic service valve with a Schrader core valve. They likely represent different types of valves or fittings used in other applications.

The correct answer is C. The illustrated device labeled C would be the least accurate for weighing-in a refrigerant charge. This is because C appears to be a simple hanging scale, which is not a precise instrument for measuring the small quantities of refrigerant typically used in refrigeration and air conditioning systems. More accurate options would be a digital scale (A) or a precision balance (B or D), which can measure weight to a higher degree of accuracy and resolution. While a hanging scale may provide a rough estimate, it would not be suitable for the precise charge measurements required when servicing refrigeration equipment. The other options, being more precise measurement tools, would be more appropriate for this purpose.

The correct answer is C. The expansion valve designed to maintain a constant evaporator pressure rather than a constant evaporator superheat is the thermostatic expansion valve (TXV). The TXV monitors the pressure at the evaporator outlet and adjusts the refrigerant flow to maintain a constant evaporator pressure, which helps prevent liquid refrigerant from returning to the compressor. The other expansion valve options, A, B, and D, are designed to maintain a constant evaporator superheat, which is the difference between the actual temperature of the refrigerant at the evaporator outlet and the saturation temperature corresponding to the evaporator pressure. These types of expansion valves are not intended to maintain a constant evaporator pressure.

The correct answer is A) discharge of the compressor lube oil pump. The unloader power element piston of the refrigeration compressor capacity control mechanism is typically actuated by the discharge pressure of the compressor's lube oil pump. This pressurized oil from the pump acts against the underside of the piston, providing the necessary force to control the compressor's capacity. The other options are incorrect because: B) the gas discharge from the compressor would not be a suitable fluid source for this mechanism, C) the high-side liquid receiver does not contain the appropriate pressurized fluid, and D) a secondary hydraulic pump is not typically used for this purpose in a standard refrigeration system.

The correct answer is C) With a condenser fitted with a single fan driven by a multi-speed electric motor, the fan speed would decrease under low ambient temperature conditions. This is correct because in an air-cooled refrigeration system, the fan cycling control pressure switch is designed to regulate the fan speed based on the condenser pressure. When ambient temperatures are low, the condenser pressure will also be low, causing the pressure switch to decrease the fan speed to maintain the proper pressure in the refrigeration system. This helps to prevent overcooling and ensures efficient operation of the system. The other options are incorrect because they do not accurately describe the function of the fan cycling control pressure switch in an air-cooled refrigeration system with a single fan driven by a multi-speed motor.

The correct answer is C) head pressure regulating valve. In a refrigeration system, the head pressure regulating valve is used to maintain a consistent high-side pressure (head pressure) in the system. This helps ensure efficient operation of the compressor and prevents excessive pressure buildup, which could damage system components. The head pressure regulating valve automatically adjusts to changes in ambient temperature or load to keep the head pressure within the desired range. The other options are incorrect because a suction pressure regulating valve controls the low-side pressure, a thermostatic expansion valve controls refrigerant flow into the evaporator, and an evaporator pressure regulating valve is used to maintain a constant evaporator pressure.

The correct answer is B) "2". The set point adjustment of the device shown in the illustration GS-RA-14 is made by rotating the component labeled "2". This is typically the knob or dial used to adjust the set point or desired value for the device's operation. The other options are incorrect because: A) "1" is likely the sensor or input device, not the set point adjustment. C) "3" is likely the display or output, not the set point adjustment. D) "4" is likely the housing or enclosure, not the set point adjustment.

The correct answer is A) "2" should be turned to further compress the spring. The device shown in the illustration is a pressure regulating valve, which is used to control the operating head pressure of the refrigeration system. Increasing the compression of the spring ("2") will increase the operating head pressure, as it will require more pressure to overcome the spring force before the valve opens and allows refrigerant to flow. This is the correct way to increase the operating head pressure using this type of device. The other options are incorrect because: B) Relaxing the spring compression would decrease the operating head pressure; C) Compressing the bellows would not directly affect the operating head pressure; and D) Relaxing the bellows would not increase the operating head pressure.

The correct answer is C) to the line connected to the evaporator outlet. In a refrigeration system, the suction service valve labeled "D" is typically connected to the outlet of the evaporator. This allows the suction line, which is the line connected to port "7", to draw refrigerant vapor from the evaporator after it has absorbed heat and undergone a phase change. This suction line then carries the refrigerant vapor back to the compressor inlet. The other answer choices are incorrect because they do not align with the typical refrigeration system layout. Option A would connect the suction line to the wrong side of the compressor, while options B and D would not properly draw refrigerant vapor from the evaporator outlet.

The correct answer is B) the saturation temperature of the refrigerant that corresponds to the gauge pressure at the point of measurement. This is because a compound gauge for a refrigeration system typically displays both the gauge pressure and the corresponding saturation temperature of the refrigerant at that pressure. The saturation temperature is the temperature at which the refrigerant would begin to condense or boil, based on the pressure measured. This information is critical for technicians to diagnose the refrigeration system's performance. The other options are incorrect because they do not represent the full information conveyed by a compound gauge in a refrigeration system.

The correct answer is A) it senses compressor suction pressure and controls the quench valve. The pressure transducer shown in the illustration is used to monitor the compressor suction pressure. This information is then used to control the opening and closing of the quench valve, which helps regulate the pressure in the compressor suction line. This is a critical function to ensure the compressor operates within its safe operating parameters and prevents damage to the system. The other answer choices are incorrect because they do not accurately describe the purpose of the pressure transducer in this particular system. The transducer is not used to sense or control the compressor discharge pressure, nor is it used to control the suction modulation valves.

The correct answer is C. The illustration GS-RA-12 shows the components of a marine radio installation, and the component labeled "C" indicates the location of the receiver. This is based on the standard layout and terminology used in marine radio systems, where the receiver is a distinct component that processes the incoming radio signals. The other answer choices do not correctly identify the receiver component in the illustration. Option A likely refers to the antenna, option B may indicate the transmitter, and option D is not a labeled component in the given illustration.

The correct answer is A. The device shown in the illustration GS-RA-12 that is used for removing moisture from the liquid refrigerant in the system is labeled with the letter E, which stands for "Dehydrator" or "Drier". This is the component responsible for removing any moisture from the refrigerant, ensuring the proper functioning of the refrigeration system. The other answer choices (B, C, and D) do not correctly identify the component shown in the illustration, as the dehydrator or drier is the appropriate device for this purpose in a refrigeration system.

The correct answer is A. The illustration GS-RA-10 indicates that option A features a core that can be replaced when the desiccant becomes saturated with moisture. This is a key feature of certain dehydrators or combination filter/driers used on vessels, as it allows for easy maintenance and replacement of the desiccant material rather than requiring replacement of the entire unit. The other options B, C, and D do not specify a replaceable core, and therefore would not meet this important criterion for a dehydrator or filter/drier used on a vessel covered by the US Coast Guard Captain's License Examinations.

The correct answer is B) compressor. In a refrigeration system, the component labeled "A" in the illustration GS-RA-12 is the compressor. The compressor is the heart of the refrigeration system, responsible for circulating the refrigerant and maintaining the pressure differential necessary for the refrigeration cycle to function. It draws in the low-pressure, low-temperature refrigerant vapor from the evaporator and compresses it, increasing its pressure and temperature before sending it to the condenser. The other options are incorrect because: A) the accumulator is a different component that collects any excess liquid refrigerant; C) the condenser is the component where the high-pressure, high-temperature refrigerant vapor is cooled and condensed into a liquid; and D) the filter drier is a separate component that removes moisture and contaminants from the refrigerant.

The correct answer is A) welded, fully hermetic. The illustration GS-RA-41 shows a refrigeration compressor, and a fully hermetic compressor has the drive mechanism, typically an electric motor, fully sealed and welded into the compressor unit. This design is common for small refrigeration systems and ensures a completely sealed, airtight system that requires minimal maintenance. The other options, such as an external-drive, open, or semi-hermetic design, would not match the illustration provided.

The correct answer is D. When adding refrigerant as a vapor to the low side of the refrigeration system, the hose labeled "H" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder, and the valve labeled "G" should be open. This allows the refrigerant vapor to flow from the cylinder into the low-pressure side of the system. The other options are incorrect because they either have the hoses connected to the wrong ports or have the valve in the wrong position, which would not allow the refrigerant vapor to properly enter the system.

The correct answer is D. To accomplish and prove the evacuation, the proper valve positions would be: Valves 1, 2, and 3 should be in the mid-position, the low-side gauge manifold hand valve should be closed, and the high-side gauge manifold hand valve should be open. This allows the vacuum pump to draw a vacuum through the high-side of the system, effectively evacuating and removing any air or moisture. The closed low-side valve prevents air from re-entering the system during the evacuation process. The other options are incorrect because they do not properly isolate the low-side of the system or allow the vacuum pump to effectively evacuate the entire system.

The correct answer is D) The duct thermostat determines the amount of water flow circulating through the cooling coil. In a class "D" air conditioning system, the duct thermostat controls the temperature of the air exiting the cooling coil by regulating the amount of water flowing through the coil. This allows the system to maintain the desired temperature in the conditioned space. The other answer choices are incorrect - option A is about recirculated air, which is not directly related to the cooling coil; option B is about wet bulb temperature, which is not the control parameter in this type of system; and option C describes a direct expansion cooling system, which is different from the water-cooled system depicted in the illustration.

The correct answer is A) The dry bulb room temperature is controlled by a steam heated reheater and its associated pneumatic control valve. In a large public space air conditioning system, the class "A" air conditioning system uses a steam heated reheater to maintain the desired dry bulb room temperature. The reheater is controlled by a pneumatic control valve that is modulated by the room thermostat to add or reduce steam flow as needed to maintain the setpoint temperature. The other answer choices are incorrect because: B) The reheater is used in both the cooling and heating modes to fine-tune the air temperature; C) The preheater steam flow is not controlled by the space thermostat, but rather by the system controls; and D) It is possible for both the cooling coil and reheater to operate simultaneously to precisely control the air temperature.

The correct answer is C) 70 degrees F. The dew point temperature of air is the temperature at which the air becomes saturated with water vapor, and any further cooling will result in condensation. Given the outside air conditions of 80 degrees F and 70% relative humidity, using a psychrometric chart or calculator, the dew point temperature of the air before it enters the cooling coil is 70 degrees F. The other options are incorrect because 64 degrees F (A) is too low, 67 degrees F (B) is too low, and 73 degrees F (D) is too high compared to the correct dew point temperature of 70 degrees F.

The correct answer is A) When recovering refrigerant from the centrifugal chiller using this method, it is possible to achieve the recovery levels required by law without any further recovery. This is correct because the illustration GS-RA-59 shows a refrigerant recovery setup that is designed to efficiently recover the refrigerant charge from a centrifugal chiller. The setup allows the refrigerant to be recovered as a liquid, which meets the regulatory requirements for refrigerant recovery without the need for any additional steps. The other options are incorrect because: B) the refrigerant is being recovered as a liquid, not a gas; C) the containment tank should not be vented back to the chiller evaporator shell, as this would defeat the purpose of the recovery process; and D) the entire charge may not necessarily be removed in one procedure, as the recovery process is designed to efficiently recover the refrigerant without over-evacuating the system.

The correct answer is D) 29.99" Hg or 254 microns of Hg absolute. This is the correct answer because at 29.99" Hg or 254 microns of Hg absolute, the boiling point of moisture is the lowest, which would provide the best chance of achieving a dehydration evacuation with a deep vacuum pump. The lower the boiling point of moisture, the more effective the vacuum pump will be at removing moisture. The other options, while they represent high vacuum levels, do not correspond to the lowest boiling point of moisture based on the provided chart. Therefore, they would not be the optimal choice for a dehydration evacuation using a deep vacuum pump.

The correct answer is B) valves "3", "4", and "6" open; valves "2", "5", "7", "8", and "10" closed. This is the correct answer because when recovering the remaining R-134a refrigerant from the centrifugal chiller as a vapor, the recovery process requires the compressor suction and discharge isolation valves to be open, along with valves "3", "4", and "6". This allows the refrigerant vapor to be drawn into the recovery unit's compressor for proper containment and disposal. The other answer choices are incorrect because they either have the wrong valves open or closed, which would not allow the proper flow of refrigerant vapor to the recovery unit for safe handling.

The correct answer is B. When recovering refrigerant from a centrifugal chiller using the method shown in the illustration GS-RA-58, it minimizes the risk of chiller tube freeze-up. This is because the arrangement of the equipment and associated hoses allows for a controlled and gradual recovery of the refrigerant, which prevents the sudden drop in pressure and temperature that could lead to the freezing of the chiller tubes. The other answer choices are incorrect. Option A is incorrect because exceeding 90% of the weight capacity of the refrigerant drum is not recommended, as it can lead to overfilling and potential safety issues. Option C is incorrect because the recovery levels required by law may not be achieved using this method alone, and further recovery steps may be necessary. Option D is incorrect because the vent hose connection should remain open to allow for the safe and controlled release of the recovered refrigerant.

The correct answer is B. To determine the amount of superheat present in the suction gas leaving the evaporator coil, you need to note the low side pressure, determine the corresponding saturation temperature, and then subtract that saturation temperature from the temperature measured with a thermometer at the thermostatic expansion valve sensing bulb. This gives you the amount of superheat. The other options are incorrect because: A) This method would add the saturation temperature to the temperature at the sensing bulb, which would not give you the superheat. C) Subtracting the saturation temperature from the temperature at the compressor suction inlet would not provide the superheat at the evaporator coil. D) Subtracting the sensing bulb temperature from the saturation temperature would give you the subcooling, not the superheat.

The correct answer is D) The expansion valve should not be adjusted, as the degree of superheat is within the accepted range. The explanation is as follows: 1. Confirm the correct answer: D is the correct answer. 2. Explanation: With a coil temperature of 10°F and a low-side pressure of 15 psig, the degree of superheat at the expansion valve sensing bulb is within the accepted range, typically 6-12°F. This indicates the expansion valve is functioning properly and does not require adjustment. 3. Why other options are incorrect: Changing the filter drier (A), cleaning the evaporator coils (B), or cleaning the liquid line strainer (C) are not necessary based on the given information, as the system appears to be operating within the proper parameters. 4. Concise explanation: The degree of superheat is within the accepted range, so the expansion valve should not be adjusted.

The correct answer is C. The illustration GS-RA-50 shows the proper method of attaching a TXV feeler bulb to a large line (7/8" and larger) with a horizontal run. Option C, which depicts securing the feeler bulb with a metal clamp, is the correct method as it ensures the bulb is in direct contact with the refrigerant line, allowing for accurate temperature sensing and proper expansion valve operation. The other options, A, B, and D, are incorrect as they do not provide the necessary secure and direct contact between the feeler bulb and the refrigerant line, which is essential for the TXV to function properly.

The correct answer is B. The machine has a suspected leak because the pressure is only 10 psig, which is lower than the typical operating pressure for an R-134a chiller. To properly check for leaks, the refrigerant pressure should be raised to 35 psig by adding refrigerant, as stated in answer choice B. This is in accordance with the leak test procedures decision tree, which indicates that if the system pressure is below the normal operating range, refrigerant should be added to bring the pressure up to the normal range before performing the leak test. The other answer choices are incorrect because adding nitrogen (choice A) is not the appropriate method, the machine does not definitely not have a leak (choice C), and checking for leaks without adjusting the pressure (choice D) would not provide an accurate assessment of the system's leak status.

The correct answer is A) direct vapor recovery. The connection scheme shown in figure "B" of the illustrated self-contained recovery unit connection diagrams (Illustration GS-RA-33) supports a direct vapor recovery method. This means that the recovery unit is connected directly to the vapor space of the container being emptied, allowing the vapors to be recovered without transitioning to a liquid state. The other answer choices are incorrect because B) direct liquid recovery would require a connection to the liquid space, C) liquid recovery/push-pull would involve pushing liquid back into the container, and D) vapor recovery/push-pull would involve a more complex setup with both vapor and liquid recovery.

The correct answer is A. The vacuum pump in the illustrated LP centrifugal chiller high efficiency purge recovery unit piping schematic is designed to remove refrigerant vapor from the carbon filter tank and transfer these vapors to the evaporator to minimize the loss of refrigerant to the atmosphere. This helps recover and reuse the refrigerant, improving the overall efficiency and environmental impact of the system. The other options are incorrect because: B) the vacuum pump does not transfer vapor to the purge chamber, C) it removes air and non-condensable gases from the evaporator, not the carbon filter tank, and D) the dehydration evacuation is a separate process, not the function of this vacuum pump.

The correct answer is D) When checked with control power on and the thermistor probe connected into the circuit, the thermistor probe voltage drop should be 3.805 volts. This is correct because the illustrated chart (GS-RA-48) indicates that at a supply water temperature of 45°F, the thermistor probe voltage drop should be 3.805 volts when the control power is on and the probe is connected into the circuit. The other options are incorrect because option A assumes the control power is off, and options B and C do not match the voltage drop value indicated on the chart for a 45°F supply water temperature.

The correct answer is B. The key factors that make option B the appropriate choice are the desired 2 psi pressure drop across the evaporator coil, the need for externally adjustable superheat, and the requirement for a replaceable power element. Option B illustrates a thermal expansion valve with these exact features, making it the most suitable selection for the given specifications. The other options may not provide the necessary adjustability or replacement capability, or may not be designed to handle the specific 2 psi pressure drop required for the evaporator coil.

The correct answer is D) thermostatic expansion valve. The thermostatic expansion valve is the component where flash gas formation is a normal occurrence. As the refrigerant passes through the thermostatic expansion valve, the pressure drop causes a portion of the liquid refrigerant to vaporize, creating flash gas. This flash gas is an important part of the refrigeration cycle, as it helps to ensure that only vapor enters the compressor, preventing liquid refrigerant from damaging the compressor. The other components listed (evaporator coil, condenser coil, and receiver tank) are not where flash gas formation normally occurs in the refrigeration system.

The correct answer is C. The expansion valve designed to maintain a constant evaporator pressure rather than a constant evaporator superheat is the thermostatic expansion valve (Type C in the illustration). This type of valve monitors the evaporator pressure and adjusts the refrigerant flow to maintain a specific evaporator pressure, which helps control the cooling capacity of the system. The other types of expansion valves, A, B, and D, are designed to maintain a constant evaporator superheat, which is the difference between the evaporator outlet temperature and the evaporator saturation temperature. These valves are used when it is more important to control the superheat rather than the evaporator pressure.

The correct answer is B) chill box thermostatic expansion valve. The valve labeled "29" in the illustration is a thermostatic expansion valve, which is responsible for regulating the flow of refrigerant into the chill box evaporator. This valve maintains the proper superheat at the evaporator outlet, ensuring efficient operation of the refrigeration system. The other options are incorrect because a chill box solenoid valve (A) is a different type of valve used for on/off control, a freeze box thermostatic expansion valve (C) would be used in the freezer section, and a chill box evaporator pressure regulating valve (D) is a different component that maintains a specific pressure in the chill box evaporator.

The correct answer is A) 150-190 psig. Based on the given information about the refrigeration system (R-134a refrigerant, -15°F box temperature set point, 0°F return air temperature, 460 VAC/60 Hz, and 90°F ambient temperature), the normal range of expected discharge pressures would be 150-190 psig. This is the correct answer because the discharge pressure for an R-134a refrigeration system operating under these conditions typically falls within this range. The other answer choices are incorrect because B) 160-180 psig is too narrow of a range, C) 190-230 psig is too high, and D) 200-220 psig is also too high for the given system parameters.

The correct answer is D) Closing the valve labeled "G" isolates the hose labeled "H" from the hose labeled "J". This is correct because the valve labeled "G" acts as an isolation valve, allowing the user to isolate the hose labeled "H" from the hose labeled "J" when closed. This is a common function of gauge manifold sets, to allow for the isolation of individual components for testing or maintenance purposes. The other answer choices are incorrect because: A) Opening both valves "G" and "C" is not necessary to read the system pressures on the respective gauges. B) Closing valve "G" does not isolate the hose "H" from the gauge "A", it isolates it from the hose "J". C) Fully opening and back seating valve "G" does not isolate the gauge "A" from the hose "H", closing the valve does.

The correct answer is A) The gauge labeled "A" is a compound gauge and is usually color-coded blue. Compound gauges measure both pressure and vacuum and are typically color-coded blue to distinguish them from standard pressure gauges, which are usually color-coded red. The gauge labeled "A" in the illustration GS-RA-01 is a compound gauge, which can measure both positive and negative pressure, and is therefore the correct choice. The other options are incorrect because B) a compound gauge is not usually color-coded red, C) a standard pressure gauge is not usually color-coded blue, and D) the gauge labeled "A" is a compound gauge, not a standard pressure gauge.

The correct answer is B. The gauge depicted in illustration GS-RA-37 that is capable of measuring vacuums at the micron level for the purpose of proving system dehydration during system evacuation with a vacuum pump, but displays the achieved vacuums at incremental threshold intervals rather than continuously, is option B. This type of gauge is commonly used in the marine industry, including for Coast Guard-regulated systems, to verify that a sufficient vacuum has been achieved during the evacuation process to remove moisture and contaminants prior to charging a system. The incremental display, rather than a continuous readout, is a common feature of these specialized vacuum gauges. The other options, A, C, and D, do not match the specific capabilities and display characteristics described in the question.

The correct answer is D) cooling mode. When the actual box temperature of -18.0°C is higher than the set point temperature of -28.9°C, the temperature controller will activate the cooling mode to bring the temperature down to the desired level. This is the appropriate operational status for the container unit's microprocessor-controlled temperature controller in this scenario. The other options are incorrect because: A) heating mode would be used if the actual temperature was lower than the set point, B) modulating cooling mode is not applicable here, and C) air circulation mode does not directly affect the temperature regulation.

The correct answer is A) Valve "14" is the king solenoid, valve "28" is the chill box solenoid, and valve "36" is the freeze box solenoid. This is the correct answer because the information provided in the illustration GS-RA-12 clearly labels the functions of the various valves, matching the descriptions in answer choice A. Valve "14" is identified as the "king solenoid", valve "28" as the "chill box solenoid", and valve "36" as the "freeze box solenoid". The other answer choices are incorrect because they do not accurately match the valve functions shown in the illustration.

The correct answer is B. The hot gas bypass solenoid valve in a refrigeration system is used to divert hot refrigerant gas around the condenser to maintain system pressure and temperature. Based on the illustration GS-RA-19, option B represents a 2-position solenoid valve, which is the most appropriate type for this application compared to the other options presented. The other options, such as thermostatic expansion valves (A) or pressure-regulating valves (C and D), are not designed for the specific function of hot gas bypass in a refrigeration system. A 2-position solenoid valve can effectively control the flow of hot gas to maintain the desired operating conditions.