Siemens SQN90.240B2793 Servo Motor Damper Actuator

Siemens SQN90.240B2793 servo motor damper actuator is a burner-mounted actuator from the SQN9 series that precisely modulates combustion air dampers and fuel valves in gas and oil burner systems. It is commonly used in HVAC heating systems, industrial boilers, furnaces, and process heating equipment where accurate air-to-fuel control improves efficiency and emissions management. The device operates from 220–240 V AC at 50–60 Hz, draws about 6–8 VA, and provides 2.4 Nm of torque through a 90° rotation with an approximate 12-second full travel time; rotation direction is counterclockwise. It supports 1-wire, 2-wire, or 3-position control and includes internal configurations with two relays and multiple switches, enabling flexible control for replacement or retrofit projects. Weight is about 0.55–0.8 kg and mounting type is burner-mounted. Common replacements include Siemens SQN90.570A2793, SQN90.240B2799, and Honeywell M7284 series damper actuators. Typical applications involve regulating air dampers and fuel valves in small to mid-range burners to maintain precise air-to-fuel ratio for safety, efficiency, and emissions control in industrial boilers, furnaces, and process heating systems.