An actuator is an electromechanical or pneumatic device that converts control signals into physical movement to regulate dampers, valves, or other mechanical components in HVAC systems. Actuators respond to commands from building automation systems, adjusting airflow, water flow, or equipment operation based on temperature, humidity, occupancy, or scheduling requirements. They enable automated control that maintains setpoints without manual intervention.
Types and Operation
Electric actuators provide precise positioning with 24-volt or 120-volt signals, offering modulating control from 0 to 100 percent opening. Pneumatic actuators use compressed air at 15 to 25 psi, delivering fast response in critical applications. Proportional control actuators maintain multiple setpoints between fully open and closed positions, enabling gradual adjustment of VAV box dampers, reheat coils, and economizer dampers to optimize energy use and comfort.
System Integration
Actuators receive feedback signals through potentiometers that report current position to the control system, enabling closed-loop control verification. Typical positioning time ranges from 10 to 30 seconds, preventing rapid cycling that causes equipment wear. Redundant feedback and failure detection features ensure safety compliance, automatically reverting to fail-safe positions during power loss or signal interruption, protecting equipment and occupant comfort.