The ______ controls the temperature of refrigerant by regulating the pressure and flow of cold refrigerant to the evaporator.

• A. Condenser
• B. Evaporator fan
• C. Thermal Expansion Valve
• D. Compressor

Answer: (C)

The device that meters and throttles refrigerant into the evaporator to set its cooling level is the thermal expansion valve. It sits between the high-pressure liquid line and the evaporator and regulates how much liquid refrigerant can enter the evaporator. By reducing the pressure of the liquid, it creates a cold, low-pressure flow that can absorb heat as it evaporates inside the evaporator. The valve adjusts its opening in response to the evaporator temperature or superheat: when more cooling is needed, it opens more to allow more refrigerant through; when less cooling is needed, it tightens to restrict flow. This precise metering keeps the evaporator at the proper temperature and prevents conditions like flooding or freezing of the coil. The condenser, evaporator fan, and compressor each perform different roles—condensing high-pressure vapor to liquid, moving air across the evaporator, and boosting refrigerant pressure, respectively—but they do not directly regulate the refrigerant’s temperature by metering flow into the evaporator.