The Belimo TFB120 is a compact spring-return (fail-safe) damper actuator delivering 22 in-lb [2.5 Nm] of torque with on/off (two-position) control on AC 100-240 V power. As Belimo's smallest spring-return class, it direct-couples to round damper shafts from 1/4 in. to 1/2 in. and, on loss of power, its internal spring returns the damper to a fail-safe position in under 25 seconds, making it a member of the TFB platform for small commercial HVAC dampers that must fail safe.
Specifications sourced from the official Belimo TFB120 technical data sheet (rev 2024-08-20).
Overview
Belimo TF-Series actuators are Belimo's smallest spring-return drives, sized for small commercial HVAC control dampers that require fail-safe operation. The TFB120 produces 22 in-lb [2.5 Nm] and mounts directly to round damper shafts from 1/4 in. to 1/2 in. with its universal clamp. On power loss the spring returns the damper to its fail-safe position in under 25 seconds; the fail-safe direction is reversible by CW/CCW mounting. Two-position on/off control drives the damper, and the spring returns it on signal or power loss.
Best for
- Small commercial HVAC dampers needing fail-safe (spring-return) operation
- Compact zone, VAV and terminal-unit damper control (22 in-lb)
- Outdoor-air and exhaust dampers that must fail safe
- Line-voltage systems (AC 100-240 V)
Key Features
Spring-Return Fail-Safe
A mechanical spring drives the damper to a safe position on power or signal loss (under 25 seconds) — no external power needed to fail safe.
Smallest 22 in-lb Class
Belimo's most compact spring-return actuator; direct-couples to round damper shafts from 1/4 in. to 1/2 in. for small dampers.
On/Off Control
Accepts two-position on/off control from a controller, relay or switch.
Reversible Fail-Safe Direction
The spring-return (fail-safe) direction is selectable clockwise or counterclockwise by mounting orientation.
Line-Voltage Power
Runs directly on AC 100-240 V line power — no separate 24 V transformer required.
cULus Listed & Quiet
Double-insulated (Class 2), cULus listed, ISO 9001 built and UL 2043 plenum-rated for long, maintenance-free service.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Belimo |
| Part Number | TFB120 |
| Actuator Type | Spring-Return (Fail-Safe) Damper Actuator |
| Nominal Voltage | AC 100-240 V |
| Nominal Frequency | 50/60 Hz |
| Power Consumption (Running) | 2.5 W |
| Torque (Motor & Spring) | 22 in-lb [2.5 Nm] (minimum) |
| Control Signal | On/Off (two-position) |
| Shaft Range | 1/4 in. to 1/2 in. [6.4-12.7 mm] via universal clamp (1/2 in. self-centering) |
| Angle of Rotation | 95° (adjustable mechanical stops) |
| Running Time (Motor) | 75 s |
| Spring Return Time | < 25 s (< 60 s below -22°F) for fail-safe |
| Behavior on Power Loss | Spring returns damper to fail-safe position |
| Fail-Safe Direction | Reversible (CW/CCW) by mounting orientation |
| Electrical Connection | 18 GA 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 / UL Type 2 |
| Ambient Temperature | -22 to 122°F [-30 to 50°C] |
| Agency Listing | cULus (UL60730-1A/-2-14, CAN/CSA) |
| Quality Standard | ISO 9001 |
| Plenum Rated | UL 2043 (suitable for air plenums) |
| Weight | 1.8 lb [0.83 kg] |
| Warranty | 5 Years |
Documentation
Related Products
Accessories & Mounting
Common Belimo accessories for mounting, linkage, signaling and powering the TFB120, drawn from the TF 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 TFB120?
The Belimo TFB120 is Belimo's smallest spring-return (fail-safe) damper actuator, for small commercial HVAC dampers. It produces 22 in-lb [2.5 Nm] of torque, uses on/off (two-position) control on AC 100-240 V power, and on power loss its spring drives the damper to a fail-safe position in under 25 seconds.
Is the TFB120 a spring-return (fail-safe) actuator?
Yes. A mechanical spring drives the damper to its fail-safe position when power or the control signal is lost — no external power is needed to fail safe.
How much torque does the TFB120 provide?
It delivers 22 in-lb [2.5 Nm] of torque. TF is Belimo's smallest spring-return class, sized for compact zone, VAV and terminal-unit dampers.
What shaft sizes does the TFB120 fit?
It direct-couples to round damper shafts from 1/4 in. to 1/2 in. using its universal clamp, self-centering at 1/2 in. A crank arm (KH-TF US) and brackets are available for off-shaft mounting.
What control signal does the TFB120 use?
It uses on/off (two-position) control. Two-position on/off control is driven from a controller, relay or switch.
What voltage does the TFB120 run on?
The TFB120 is a line-voltage actuator running on AC 100-240 V, so no separate 24 V control transformer is required.
Does the TFB120 have a manual override?
No. Like other compact spring-return actuators, the TFB120 has no manual override — the spring sets the fail-safe position and the motor drives the powered direction.
Is the Belimo TFB120 available from an authorized Belimo distributor?
Yes. ZOT Supply is an authorized Belimo distributor and carries the TFB120. Every unit ships factory new with Belimo's full 5-year warranty and application support.
- Actuator Type:
- Spring-Return (Fail-Safe)
- Torque:
- 22 in-lb
- Control Signal:
- On/Off
- Voltage:
- Line Voltage (100-240 VAC)
- Auxiliary Switch:
- No
- Series:
- TFB
