Belimo LF24-SR-S Actuator Motor

The Belimo LF24-SR-S is a high-torque spring return actuator designed for fail-safe operation in light-commercial HVAC dampers and centrifugal valves. Delivering 35 in-lb (4 Nm) of torque, this motor operates on a 2-10VDC proportional control signal, making it ideal for air handling units (AHUs) and VAV terminal deployments requiring precise modulation. Engineered for integration with 24VAC or 24VDC power supplies, the unit features a built-in SPDT auxiliary switch (1x 3mA to 3A) for end-position signaling or safety interlock confirmation. Its mechanical spring return ensures the application reaches a defined home position during power loss, providing reliable system protection. This actuator supports a wide range of mounting options and is compatible with standard damper shafts, ensuring efficient field replacement for contractors focusing on system uptime and energy-efficient building automation controls.

Key Benefits for Technicians:

• Precise Modulation: Utilize 2-10VDC feedback for accurate positioning and integration into BAS networks.
• Fail-Safe Reliability: Mechanical spring return function provides guaranteed closure or opening upon loss of power.
• Integrated Feedback: One built-in auxiliary switch reduces the need for external hardware and labor time during installation.
• Universal Power Compatibility: Flexible 24VAC/DC operation simplifies inventory management and field selection.
• Compact Footprint: Narrow design allows for installation in tight mechanical plenum spaces and small damper assemblies.

Common Technical Questions:

How do I wire the Belimo LF24-SR-S for proportional control?
Connect the 24V power to terminals 1 and 2, then apply the 2-10VDC control signal to terminal 3. Terminal 5 provides the 2-10VDC position feedback signal to your controller.

Can the auxiliary switch be adjusted in the field?
The auxiliary switch on the LF24-SR-S is fixed at 10° to signal the end position, providing a definitive status update to the building management system.

What is the maximum damper area this 35 in-lb actuator can handle?
While it depends on the damper blade type and seal friction, the Belimo LF24-SR-S is typically rated for dampers up to approximately 8 square feet.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.