What is the role of a damper actuator in a VAV system?

• A. To measure zone temperature.
• B. To power the HVAC system directly.
• C. To modulate the supply air damper position to control zone airflow.
• D. To report maintenance needs to a central system.

Answer: (C)

In a VAV system, the damper actuator provides the movement of the supply air damper in response to a control signal. It converts an electrical (or pneumatic) command into a precise damper position, modulating how much supply air reaches the zone. When more airflow is needed to reach the zone’s temperature setpoint, the actuator opens the damper; when less is needed, it closes it. This direct control of the damper position is how zone airflow is varied to maintain the desired temperature. The other options involve sensing temperature, powering the system directly, or reporting maintenance—functions that don’t involve moving the damper.