Complete HVAC EPA Certification Practice Exam

The component responsible for regulating the flow of refrigerant in an HVAC system is the expansion valve. This device is critical for controlling the amount of refrigerant that enters the evaporator coil, which is essential for maintaining the desired temperature and pressure within the system. By expanding the refrigerant, the expansion valve lowers its pressure and temperature, allowing it to absorb heat from the indoor environment effectively.

In contrast to the expansion valve, the filter drier primarily serves to remove moisture and contaminants from the refrigerant, which is important for the overall health and longevity of the system but does not regulate refrigerant flow. The air handler's main function is to circulate air throughout the space and does not play a direct role in controlling refrigerant flow. The compressor compresses the refrigerant gas and moves it through the system but does not specifically regulate its flow; that task is delegated to the expansion valve. Understanding the distinct roles of these components is crucial for effective HVAC system operation and maintenance.