Belimo NFB24-SR Spring Return Damper Actuator in-lb - 90 24V 2-10VDC

The Belimo NFB24-SR is a direct-coupled spring return damper actuator designed for proportional modulation of dampers in HVAC systems. This fail-safe actuator delivers 90 in-lb (10 Nm) of torque and operates on AC/DC 24V power with 2-10V modulating control. The actuator mounts directly to damper shafts up to 1.05" in diameter using its universal clamp, accommodating 1/2", 3/4", and 1.05" shaft sizes.

Key Features:

• True spring return operation provides reliable fail-safe application and positive close-off on air-tight dampers, delivering constant torque with or without power
• Brushless DC motor controlled by ASIC and microprocessor provides constant rotation rate, exact fail-safe positioning, and digital rotation sensing to prevent stall damage
• 95-second motor running time for 90° rotation with 95° angle of rotation
• Operates on 2-10 VDC control signal (or 4-20 mA with optional 500Ω resistor) and provides 2-10 VDC feedback signal for position indication
• Graduated position indicator shows 0° to 95°
• Reversible CW/CCW mounting with external switch, electronic overload protection throughout rotation
• 3-foot 18 AWG appliance cable with 1/2" NPT conduit connector
• Includes 5mm hex crank (3/16" Allen key) for manual override
• Operating temperature range: -22°F to 122°F (-30°C to 50°C)

The NFB24-SR features a galvanized steel and plastic housing rated NEMA 2/IP54. This actuator is CE and CSA certified, ISO 9001 listed, and UL/cULus listed with a 5-year warranty. This model replaces the legacy NF24-SR actuator. Crank arms and mounting brackets are available separately for applications where direct coupling is not possible.