Belimo LF24-S Actuator

Belimo LF24-S is a fail-safe rotary damper actuator that delivers 4 Nm (35 in-lb) of torque from a 24 V AC/DC power source and is designed for HVAC dampers. As a spring-return device, it automatically moves to its fail-safe position when power is removed, helping maintain damper position during power loss. The unit features a 75-second end-to-end travel time for open/close operation and includes a single SPDT auxiliary switch for feedback, with an IP54 enclosure for protection against dust and water splashes. Regional variations exist: EU/UK configurations use an Open/Close control, while US variants are marketed as On/Off control; both share the same 4 Nm rating and spring-return behavior. A direct-coupled LF24-S US variant is documented, and Belimo notes dampers up to about 0.8 m² as a practical sizing guideline. This actuator is part of Belimo’s fail-safe lineup and is suitable for retrofit or new installations where a reliable, self-contained 24 V damper drive with built-in feedback is required.