The Belimo EFX120-SR N4 is a high-torque spring-return (fail-safe) damper actuator delivering 270 in-lb [30 Nm] of torque with modulating 2-10 VDC control on AC 100-240 V power. It direct-couples to round or square damper shafts up to 1.05 in. with a universal clamp and is part of Belimo's configurable EFX platform for large commercial HVAC dampers that must fail to a safe position. On power loss the internal spring drives the damper to its fail-safe position in under 20 seconds. The watertight NEMA 4 housing suits washdown and outdoor service.
Specifications sourced from the official Belimo EFX120-SR N4 technical data sheet (rev 2026-03-09).
Overview
Belimo EF-Series actuators are high-torque spring-return drives for large commercial HVAC control dampers requiring fail-safe operation. The EFX120-SR N4 produces 270 in-lb [30 Nm] and mounts directly to round or square damper shafts up to 1.05 in. with its universal clamp (a crank arm and brackets are available for jackshaft and linkage applications). The fail-safe direction is reversible by CW/CCW mounting, and a 5 mm hex crank allows manual positioning. The spring returns the damper to its fail-safe position in under 20 seconds when power is removed. A 2-10 VDC signal (or 4-20 mA with the ZG-R01 resistor) modulates the damper, with 2-10 VDC position feedback; the spring provides fail-safe return.
Best for
- Modulating large-damper control with fail-safe return
- High-torque damper and louver control (270 in-lb)
- Outdoor-air, mixing-box and economizer dampers that must fail safe
- Washdown / wet / outdoor locations (NEMA 4)
- 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 20 seconds), with no external power required to fail safe.
270 in-lb High Torque
Sized for large commercial dampers; direct-couples to round or square damper shafts up to 1.05 in. with a universal clamp.
Modulating 2-10 VDC
Accepts a 2-10 VDC (or 4-20 mA with ZG-R01) signal with 2-10 VDC position feedback.
Reversible Fail-Safe Direction
The spring-return (fail-safe) direction is selectable clockwise or counterclockwise simply by mounting orientation.
Manual Override Crank
A supplied 5 mm hex crank (3/16" Allen) lets you position the damper by hand for setup or service.
NEMA 4 Watertight
A watertight NEMA 4 / UL Type 4 housing suits washdown, wet and outdoor installations.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Belimo |
| Part Number | EFX120-SR N4 |
| Actuator Type | Spring-Return (Fail-Safe) Damper Actuator |
| Nominal Voltage | AC 100-240 V |
| Nominal Frequency | 50/60 Hz |
| Power Consumption (Running) | 9.5 W |
| Transformer Sizing | 21 VA |
| Torque (Motor & Spring) | 270 in-lb [30 Nm] (minimum, full rotation) |
| Control Signal | Modulating |
| Operating Range (Y) | 2-10 VDC (4-20 mA with ZG-R01 resistor) |
| Position Feedback (U) | 2-10 VDC (max. 1 mA) |
| Shaft Range | Up to 1.05 in. [26.7 mm] via universal clamp; crank arm available |
| Angle of Rotation | 95° (adjustable mechanical stops) |
| Running Time (Motor) | 95 s / 90° |
| Spring Return Time | < 20 s (< 60 s below -4°F) for fail-safe |
| Behavior on Power Loss | Spring returns damper to fail-safe position |
| Fail-Safe Direction | Reversible (CW/CCW) by mounting orientation |
| Manual Override | 5 mm hex crank (3/16" Allen), supplied |
| Electrical Connection | 18 AWG plenum 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 4 / UL Type 4 (watertight) |
| Ambient Temperature | -22 to 122°F [-30 to 50°C] |
| Agency Listing | cULus (UL60730-1A/-2-14, CAN/CSA) |
| Quality Standard | ISO 9001 |
| Weight | 10 lb [4.7 kg] |
| Warranty | 5 Years |
Documentation
Related Products
Accessories & Mounting
Common Belimo accessories for mounting, linkage, signaling and powering the EFX120-SR N4, 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 EFX120-SR N4?
The Belimo EFX120-SR N4 is a high-torque spring-return (fail-safe) damper actuator for large commercial HVAC dampers. It produces 270 in-lb [30 Nm] of torque, uses modulating 2-10 VDC control on AC 100-240 V power, and on power loss its spring drives the damper to a fail-safe position. Its housing is rated NEMA 4.
Is the EFX120-SR N4 a spring-return (fail-safe) actuator?
Yes. The EFX120-SR N4 is spring-return: 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.
What happens to the EFX120-SR N4 on power loss?
Its internal spring returns the damper to the fail-safe position in < 20 s (< 60 s below -4°F). The fail-safe direction (CW or CCW) is set by the mounting orientation.
How much torque does the EFX120-SR N4 provide?
It delivers 270 in-lb [30 Nm] of minimum running and spring-return torque, sizing it for large commercial dampers.
What shaft sizes does the EFX120-SR N4 fit?
It direct-couples to round or square damper shafts up to 1.05 in. using its universal clamp. For jackshafts or off-shaft mounting, a crank arm (KH-EFB) and brackets (ZG-120, ZG-JSA-3) are available.
What control signal does the EFX120-SR N4 use?
It uses modulating 2-10 VDC control. The 2-10 VDC input also accepts 4-20 mA with the ZG-R01 resistor and provides 2-10 VDC feedback.
Is the EFX120-SR N4 suitable for outdoor or wet locations?
Yes. The EFX120-SR N4 has a watertight NEMA 4 / UL Type 4 housing suitable for washdown, wet and outdoor installations.
What voltage does the EFX120-SR N4 run on?
The EFX120-SR N4 is a line-voltage actuator running on AC 100-240 V, so no separate 24 V control transformer is required.
How do you manually position the EFX120-SR N4?
Use the supplied 5 mm hex crank (3/16" Allen) to wind the actuator by hand for setup or service.
Is the Belimo EFX120-SR N4 available from an authorized Belimo distributor?
Yes. ZOT Supply is an authorized Belimo distributor and carries the EFX120-SR N4. Every unit ships factory new with Belimo's full 5-year warranty and application support.
- Actuator Type:
- Fail-Safe
- Torque:
- 270 in-lb
- Control Signal:
- Modulating
- Voltage:
- Line Voltage (100-240 VAC)
- Auxiliary Switch:
- No
- Enclosure:
- NEMA 4
- Series:
- EF
- Feedback Signal:
- 2-10 VDC
