Question 222Refrigeration & AC - Assistant Engineer

The correct answer is D) liquid line box solenoid. In a refrigeration system with low-side pump down, the temperature of the refrigerated space is controlled by a thermostat wired to the liquid line box solenoid. This solenoid valve is responsible for opening and closing the liquid line, which regulates the flow of refrigerant to the evaporator. When the thermostat senses the temperature dropping below the set point, it signals the liquid line box solenoid to open, allowing refrigerant to flow into the evaporator and cool the space. Conversely, when the temperature reaches the set point, the thermostat signals the solenoid to close, shutting off the refrigerant flow. The other options are incorrect because they do not directly control the temperature of the refrigerated space. The suction line solenoid (A) and low-pressure cutout switch (C) are not involved in the temperature control process, while the thermostatic expansion valve (B) controls the flow of refrigerant to the evaporator but is not wired to the thermostat.