Belimo NFB24-MFT-S Spring Return Damper Actuator, 90 in-lb, 24V

Description

The Belimo NFB24-MFT-S is a heavy-duty, spring return damper actuator engineered for reliable, fail-safe operation in commercial HVAC and building automation applications. Delivering 90 in-lb of torque and powered by 24 Vac/Vdc, this multi-function actuator supports a wide range of control signal types — making it one of the most versatile actuators in the Belimo N-Series lineup.

Built with Belimo’s proven spring return mechanism, the NFB24-MFT-S automatically returns the damper to its fail-safe position upon loss of power, ensuring system safety and code compliance in critical air handling and ventilation systems.

Key Features

• Spring return, fail-safe operation for reliable damper positioning
• 90 in-lb torque output — suitable for medium to large damper applications
• Multi-function technology (MFT) supports multiple control signal types in a single unit
• 500 Ohm input impedance for 4–20 mA proportional control
• 1500 Ohm input impedance for PWM (pulse-width modulation) control
• Floating point (tri-state) control compatible
• On/Off control compatible
• Dual voltage: 24 Vac and 24 Vdc operation
• Integrated auxiliary switch for end-position feedback or interlocking

Control Signal Compatibility

• 4–20 mA proportional (500 Ohm input impedance)
• PWM proportional (1500 Ohm input impedance)
• Floating point (3-point)
• On/Off (2-point)

Electrical Specifications

• Supply voltage: 24 Vac / 24 Vdc
• Control signal: 4–20 mA, PWM, floating point, On/Off
• Input impedance: 500 Ohm (4–20 mA) / 1500 Ohm (PWM)
• Includes auxiliary switch for position feedback

Applications

• Variable air volume (VAV) systems
• Air handling units (AHUs)
• Outdoor air and exhaust damper control
• Building automation and BAS integration
• Economizer and ventilation control

The NFB24-MFT-S is the ideal choice for contractors and engineers who need a single actuator that adapts to virtually any control system — eliminating the need for multiple SKUs on the job site. Backed by Belimo’s industry-leading quality and reliability, this actuator is a trusted solution for commercial and light industrial HVAC installations.