Siemens Servo actuator SQM40.265A20

Siemens SQM40.265A20 is an electromechanical actuator for positioning air dampers in burner systems. It operates during pre-purge, ignition, and modulation phases, converting an electrical control signal into rotational movement to adjust the damper. This actuator is part of the SQM40 series and is intended for use with Siemens burner controls.

When selecting a replacement actuator, verify the required torque, running time for full stroke, control signal type (three-point floating, 0-10 V analogue, or on/off), shaft or coupling pattern, angle of rotation, and the presence of integral auxiliary switches for end-position feedback or interlock. Before fitting, confirm that electrical connections and mechanical coupling match the existing installation and that the control signal from the burner controller is compatible with the actuator’s input specification.

Typical failure modes for this kind of actuator include stripped gear trains, worn end switches, and seized shafts after prolonged standstill. During inspection, focus on these components.