The Belimo AFX24 is a spring-return (fail-safe) damper actuator delivering 180 in-lb [20 Nm] of torque with on/off on 24 VAC/DC power. It direct-couples to damper shafts up to 1.05 in. diameter and drives to a mechanical fail-safe position on power loss, making it part of the newer, field-configurable AFX platform for commercial HVAC damper control.
Specifications sourced from the official Belimo AFX24 technical data sheet (rev 2024-12-12).
Overview
Belimo AF-Series actuators are spring-return (fail-safe) drives for commercial HVAC dampers. The AFX24 produces 180 in-lb [20 Nm] of torque, mounts directly to the damper shaft, and On loss of power the spring drives the damper to its defined fail-safe position within the rated fail-safe time. Two-position on/off control opens or closes the damper from any auxiliary contact or manual switch.
Best for
- Commercial HVAC damper control (180 in-lb damper torque)
- Fail-safe (spring return) applications requiring positive close-off
- Direct shaft mount up to 1.05 in. diameter
Key Features
True Spring Return Fail-Safe
Constant-torque spring drives the damper to a defined safe position on power loss — no mechanical end switches required, and positive close-off on air-tight dampers.
180 in-lb Torque
Sizes a wide range of commercial dampers; up to two AF actuators can be piggybacked for loads to 266 in-lb on a 3/4" minimum shaft.
Simple On/Off Control
Driven open/closed from any auxiliary contact or manual switch — the workhorse choice for two-position damper control.
Plenum-Rated & Quiet
UL 2043 plenum rated for use in air-handling spaces, double-insulated (Class 2), cULus listed and built to ISO 9001.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Belimo |
| Part Number | AFX24 |
| Actuator Type | Spring-Return (Fail-Safe) Damper Actuator |
| Nominal Voltage | AC/DC 24 V |
| Nominal Voltage Range | AC 19.2-28.8 V / DC 21.6-28.8 V |
| Nominal Frequency | 50/60 Hz |
| Power Consumption (Running) | 5 W |
| Power Consumption (Holding) | 2.5 W |
| Transformer Sizing | 7.5 VA |
| Torque | 180 in-lb [20 Nm] |
| Control Signal | On/Off (open/close from auxiliary contact or switch) |
| Angle of Rotation | 95° (adjustable end stop 35-95°) |
| Running Time (Motor) | 75 s / 90° |
| Running Time (Fail-Safe) | <20 s @ -4 to 122°F [-20 to 50°C]; <60 s @ -22°F [-30°C] |
| Manual Override | 5 mm hex crank (3/16" Allen), supplied |
| Direction of Motion | Selectable CW/CCW |
| Position Indication | Mechanical |
| Electrical Connection | 18 AWG appliance cable, 3 ft [1 m], 1/2" NPT conduit connector |
| Overload Protection | Electronic, full 0-95° rotation |
| Electrical Protection | Double insulated (Class 2) |
| Enclosure Rating | NEMA 2 / IP54 / UL Type 2 |
| Housing Material | UL94-5VA |
| Ambient Temperature | -22 to 122°F [-30 to 50°C] |
| Storage Temperature | -40 to 176°F [-40 to 80°C] |
| Agency Listing | cULus (UL60730-1A / -2-14, CAN/CSA) |
| Quality Standard | ISO 9001 |
| Plenum Rated | UL 2043 (suitable for air plenums) |
| Weight | 4.7 lb [2.1 kg] |
| Warranty | 5 Years |
Documentation
Related Products
Accessories & Mounting
Common Belimo accessories for mounting, linkage, signaling and powering the AFX24, drawn from the actuator datasheet. All are stocked by ZOT Supply as an authorized Belimo distributor.
Mounting & Linkage
Electrical Add-Ons
Frequently Asked Questions
What is the Belimo AFX24?
The Belimo AFX24 is a spring-return (fail-safe) damper actuator for commercial HVAC. It produces 180 in-lb [20 Nm] of torque, uses on/off (open/close) control on 24 VAC/DC power, and drives the damper to a mechanical fail-safe position on loss of power. Its housing is rated NEMA 2 / IP54 / UL Type 2.
How does the AFX24 fail safe on power loss?
The AFX24 stores energy in a return spring during normal operation. When power is lost, the spring drives the damper to its defined safe position — no capacitors or batteries, and no mechanical end switches required. It is shipped pre-tensioned about 5° for tight shut-off on gasketed dampers.
What torque does the AFX24 provide and what shaft sizes does it fit?
It delivers 180 in-lb [20 Nm] and direct-couples to round or square damper shafts up to 1.05 in. diameter using its universal clamp. Up to two AF actuators can be piggybacked for loads to 266 in-lb on a 3/4 in. minimum shaft.
What control signal does the AFX24 use?
It uses on/off (open/close) control. On/Off is driven from any auxiliary contact, relay or manual switch.
What is the running time of the AFX24?
Motor running time is about 75 seconds for 90° of travel, and the spring-return fail-safe time is under 15 seconds at normal temperatures (under 60 seconds at -22°F [-30°C]).
What is the difference between the Belimo AFX24 and the AFB24?
Both share the same 180 in-lb spring-return mechanics, mounting and fail-safe operation. The AFX24 is built on Belimo's newer, field-configurable AFX platform; the AFB24 is the established AFB version. For most damper applications they are interchangeable.
Is the AFX24 UL listed for damper control?
Yes. The AFX24 is cULus listed to UL60730 and CAN/CSA, is double-insulated (Class 2), and is UL 2043 plenum-rated for installation in air-handling spaces.
Is the Belimo AFX24 available from an authorized Belimo distributor?
Yes. ZOT Supply is an authorized Belimo distributor and carries the AFX24. Every unit ships factory-new with Belimo's full 5-year warranty and application support from our team.
- Actuator Type:
- Fail-Safe
- Torque:
- 180 in-lb
- Control Signal:
- On/Off
- Voltage:
- 24 VAC/DC
- Auxiliary Switch:
- No
- Enclosure:
- NEMA 2
- Series:
- AF
