Belimo LF24-SR Actuator

The Belimo LF24-SR is a dedicated spring-return actuator designed for modulating control in HVAC systems, providing 35 in-lb torque for dampers and valves. Running on a 24VAC/DC power supply, it utilizes a 2-10VDC control signal to deliver precise proportional positioning. This direct-coupled actuator features a mechanical spring return system, ensuring a fail-safe position during power loss—a critical requirement for smoke control or outdoor air intake dampers. Built for longevity in rigorous environments, the LF24-SR supports universal mounting with a reversible rotation direction, simplifying field installation. Its brushless DC motor technology eliminates the need for limit switches, protecting the unit from stall conditions by automatically adjusting the stroke length. For contractors managing proportional damper control, this unit offers a reliable analog output signal for position feedback, ensuring high-performance air handling and environmental control.

• Fail-Safe Operation: Reliable mechanical spring return ensures the damper reaches its safety position during power interruptions.
• Universal Compatibility: The 35 in-lb torque rating and adjustable 2-10VDC signal make it compatible with most standard building automation systems.
• Simplified Installation: No special tools are required for the universal shaft clamp, and the direction of rotation is easily toggled via a switch.
• Energy Efficiency: Low power consumption during holding cycles reduces the overall electrical load on the class 2 transformer.
• Maintenance Free: The brushless DC motor is designed for high-cycle life without the need for periodic calibration.

How do I reverse the fail-safe direction on the LF24-SR?
The direction of the spring return is determined by the orientation of the actuator on the shaft; simply flip the unit to change between normally open (NO) and normally closed (NC) fail-safe positions.

Can this actuator be used with a 4-20mA control signal?
Yes, by installing a 500-ohm resistor across the input terminals, the 2-10VDC signal can be converted to accept a standard 4-20mA input.

What is the typical runtime for the LF24-SR?
The motor drive time is approximately 150 seconds for 95 degrees markers, while the spring return fail-safe closes in less than 25 seconds at room temperature.

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.