HVAC Metering Devices Practice Test 2025 – 400 Free Practice Questions to Pass the Exam

The purpose of an automatic expansion valve is to regulate refrigerant flow based on pressure. This type of valve adjusts its opening to maintain a constant pressure in the evaporator, which is crucial for efficient system operation. By responding dynamically to the pressure changes within the system, the valve ensures that the right amount of refrigerant enters the evaporator coil, optimizing the cooling process and enhancing energy efficiency.

Maintaining proper pressure is essential for the evaporator to support the heat exchange process adequately. When the pressure rises, the valve restricts the flow of refrigerant, and when the pressure drops, it allows more refrigerant to pass through. This automatic adjustment facilitates smooth operation under varying load conditions, helping to prevent issues such as flooding or starving of the evaporator.

The other options, while related to refrigerant management, do not capture the primary function of the automatic expansion valve as accurately as the regulation of refrigerant based on pressure. For example, maintaining a constant flow rate is more commonly associated with other types of valves or devices that focus on flow control rather than pressure regulation. Balancing refrigerant flow involves different strategies and components, and preventing system freezing is a broader concern that can involve multiple aspects of system design and management, not just the action of an