What is the primary function of an expansion valve in an HVAC system?

The primary function of an expansion valve in an HVAC system is to regulate the flow and pressure of refrigerant into the evaporator. As the refrigerant passes through the expansion valve, it experiences a drop in pressure, which allows it to expand and cool before entering the evaporator coil. This process is crucial because it enables the refrigerant to absorb heat from the indoor air, facilitating the cooling process. Maintaining the appropriate flow and pressure of refrigerant is essential for the efficient operation of the system, ensuring optimal heat exchange in the evaporator and preventing issues such as flooding or starvation of the evaporator coil. This vital role makes the expansion valve a key component in maintaining the balanced operation of the entire HVAC system.