What is the function of a dampers actuator in an HVAC system controlled by DDC?

• A. Adjusts air flow by moving dampers to regulate mix and supply air.
• B. Controls temperature setpoint for spaces.
• C. Provides alarm notifications for sensor faults.
• D. Stores historical data for energy usage.

Answer: (A)

Dampers and their actuators are the mechanism that translates digital control signals into physical movement to regulate air flow in an HVAC system. In a DDC-controlled setup, the damper actuator receives a commanded position from the controller and moves the damper blades to adjust how much outdoor air is mixed with return air and how much air is sent to the spaces. This changes the supply air volume and its mix, helping meet ventilation and temperature goals while also supporting energy efficiency.

It's not about setting a space temperature setpoint directly—that's handled by the control loop using sensor feedback. It doesn't provide alarm notifications for sensor faults, and it doesn't store historical data; those functions come from monitoring/historians and alarms systems. So the essential role is to adjust air flow by moving dampers to regulate mix and supply air.