Nate Core Practice Test 2025 - Free Practice Questions and Study Guide.

The correct choice is pressure switches because their primary function in an HVAC system is to monitor and regulate the pressure within the system. These devices activate or deactivate components based on predetermined pressure levels, ensuring that the system operates within safe and efficient parameters. By doing so, pressure switches play a critical role in preventing issues such as overpressure or underpressure, which can lead to equipment failure or inefficient operation.

The other components do not directly manage system pressure. A thermostat primarily regulates temperature by controlling the heating or cooling output of the system. Blowers are responsible for moving air throughout the system but do not impact pressure levels. Filter dryers serve to remove moisture and contaminants from refrigerants but are not designed to regulate pressure. Understanding the specific functions of each component helps clarify why pressure switches are essential in maintaining proper system pressure in HVAC applications.