Belimo AFB24-SR Actuator

The Belimo AFB24-SR Actuator is a heavy-duty, 24V spring return solution engineered for precise modulating control in demanding HVAC environments. Built to drive control dampers in AHUs and VAV systems, this 180 in-lb actuator (20 Nm) utilizes a 2-10VDC control signal to provide accurate positioning and reliable fail-safe operation. The brushless DC motor technology ensures a consistent 95-second motor run time, while the mechanical spring return provides a fast fail-safe response in under 20 seconds during power loss. With a NEMA 2 rated housing and a universal bolt-on clamp that fits shafts from 1/2 inch to 1.05 inches, the Belimo AFB24-SR is designed for straightforward integration into existing building automation systems. Performance is further enhanced by a manual override crank and a selectable direction of motion switch to accommodate various mounting configurations.

Key Benefits for Contractors

• High-Torque Performance: Delivers 180 in-lb to handle large damper surfaces and high-pressure drops.
• Precise Modulation: Responds to 2–10VDC or 4–20mA signals for granular airflow control.
• Dual-Voltage Compatibility: Operates on both 24 VAC and 24 VDC for versatile field power options.
• Fail-Safe Reliability: Mechanical spring return ensures the damper returns to the safe position during power interruptions.
• Simplified Installation: Features a universal shaft clamp and an adjustable anti-rotation strap for secure mounting.

Common Questions

What is the difference between the AFB24-SR and the AF24-SR?
The AFB series is the updated performance line from Belimo, offering higher torque (180 in-lb vs 133 in-lb) and increased efficiency over the older AF series models.

Can this actuator be used with 4-20mA control signals?
Yes, by using a 500 Ω resistor across the input leads, the 2-10VDC signal input can be converted to accept a 4-20mA signal.

How do I change the fail-safe direction?
The fail-safe direction (Clockwise or Counter-Clockwise) is determined by how the actuator is mounted to the shaft; simply flip the actuator to change the spring return direction.

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.