Spring-return actuator AC / DC 24 V, Open/Close, 15 Nm, 133 in/lb, 2 x SPDT Running time motor approx. 75 s Running time, spring-return < 20 s Control Open/Close with single-wire contact Auxiliary switch 2 integral Safety function with spring Connection cable with conduit connector and 2 single wires
The Belimo FSAF24A-S US Fire & Smoke Actuator is a high-torque, UL-listed spring-return actuator designed for critical fire and smoke damper applications in commercial HVAC systems. Delivering 180 in-lb (20 Nm) torque, 24V AC/DC operation, and integrated auxiliary switches, this actuator ensures reliable fail-safe performance and real-time position feedback for life safety systems.
Apex Controls supplies genuine Belimo fire and smoke actuators with fast U.S. shipping for contractors, OEMs, and facility professionals.
Overview
The FSAF24A-S US is engineered for large fire and smoke dampers, where higher torque and dependable fail-safe operation are required. It operates on 24V AC/DC power and uses on/off control, making it ideal for integration into building automation and life safety systems.
This actuator includes two auxiliary switches for position indication, allowing confirmation of damper status during normal operation and emergency conditions.
Key Features
- 180 in-lb (20 Nm) torque for larger dampers
- Spring return (fail-safe) operation
- 24V AC/DC power supply
- On/Off control
- 2 × SPST auxiliary switches for position feedback
- Fast response time (~25 seconds motor, <15 seconds spring return)
- Direct-coupled mounting (no linkage required)
- Designed for UL555 and UL555S fire/smoke damper compliance
The spring-return mechanism ensures the damper automatically moves to its safe position during power loss or emergency events.
Applications
The Belimo FSAF24A-S US is commonly used in:
- Large fire and smoke dampers
- Combination fire/smoke HVAC systems
- High-rise commercial buildings
- Hospitals and healthcare facilities
- Schools and institutional buildings
It is specifically designed for life safety applications, where actuator reliability and compliance are critical.
Technical Specifications
| Specification | Details |
|---|---|
| Torque | 180 in-lb (20 Nm) |
| Voltage | 24V AC/DC |
| Control Type | On/Off |
| Fail-Safe | Yes (spring return) |
| Auxiliary Switches | 2 × SPST |
| Running Time | ~25 seconds |
| Fail-Safe Time | <15 seconds |
| Rotation | 95° |
| Mounting | Direct coupled |
(OLD p/n FSAF24-S)



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