A HVAC actuator is a device that is used to control the flow of air in a heating, ventilation, and air conditioning (HVAC) system. It is a mechanical device that is connected to a motor, which is used to open and close dampers, valves, and other components in the system. The actuator is usually connected to a thermostat, which is used to detect changes in temperature and then send a signal to the actuator to adjust the flow of air accordingly. This helps to ensure that the temperature in the space is maintained at a comfortable level. HVAC actuators are an essential component of any HVAC system, as they are responsible for controlling the air flow and temperature in the space. They are typically installed in commercial and residential buildings, as well as in industrial settings.