The Belimo NFXUP N4 is a robust spring-return (fail-safe) damper actuator delivering 90 in-lb [10 Nm] of torque with two-position on/off control on AC 24-240 V / DC 24-125 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 NFX platform for 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 NFXUP N4 technical data sheet (rev 2025-04-28).
Overview
Belimo EF-Series actuators are spring-return drives for commercial HVAC control dampers requiring fail-safe operation. The NFXUP N4 produces 90 in-lb [10 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. Two-position on/off control drives the damper open and the spring returns it on signal or power loss.
Best for
- Commercial HVAC dampers needing fail-safe (spring-return) operation
- Medium-torque damper and louver control (90 in-lb)
- Outdoor-air, mixing-box and economizer dampers that must fail safe
- Washdown / wet / outdoor locations (NEMA 4)
- Multi-voltage systems (AC 24-240 V / DC 24-125 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.
90 in-lb Torque
Sized for mid-size commercial dampers; direct-couples to round or square damper shafts up to 1.05 in. with a universal clamp.
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 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 | NFXUP N4 |
| Actuator Type | Spring-Return (Fail-Safe) Damper Actuator |
| Nominal Voltage | AC 24-240 V / DC 24-125 V |
| Nominal Frequency | 50/60 Hz |
| Power Consumption (Running) | 6 W |
| Torque (Motor & Spring) | 90 in-lb [10 Nm] (minimum, full rotation) |
| Control Signal | On/Off (two-position, 1 or 3-wire) |
| 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) | 75 s / 90° |
| Spring Return Time | < 20 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 |
| 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 4X / UL Type 4X (watertight, corrosion-resistant) |
| Ambient Temperature | -22 to 122°F [-30 to 50°C] |
| Agency Listing | cULus (UL60730-1A/-2-14, CAN/CSA) |
| Quality Standard | ISO 9001 |
| Weight | 9.3 lb [4.2 kg] |
| Warranty | 5 Years |
Documentation
Related Products
Accessories & Mounting
Common Belimo accessories for mounting, linkage, signaling and powering the NFXUP 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 NFXUP N4?
The Belimo NFXUP N4 is a robust spring-return (fail-safe) damper actuator for commercial HVAC dampers. It produces 90 in-lb [10 Nm] of torque, uses two-position on/off control on AC 24-240 V / DC 24-125 V power, and on power loss its spring drives the damper to a fail-safe position. Its housing is rated NEMA 4X.
Is the NFXUP N4 a spring-return (fail-safe) actuator?
Yes. The NFXUP 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 NFXUP N4 on power loss?
Its internal spring returns the damper to the fail-safe position in < 20 s (< 60 s below -22°F). The fail-safe direction (CW or CCW) is set by the mounting orientation.
How much torque does the NFXUP N4 provide?
It delivers 90 in-lb [10 Nm] of minimum running and spring-return torque, sizing it for mid-size commercial dampers.
What shaft sizes does the NFXUP 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-AFB) and brackets (ZG-100, ZG-118) are available.
What control signal does the NFXUP N4 use?
It uses two-position on/off control. On/Off control is driven from a controller, relay or switch.
Is the NFXUP N4 suitable for outdoor or wet locations?
Yes. The NFXUP N4 has a watertight NEMA 4 / UL Type 4 housing suitable for washdown, wet and outdoor installations.
What does UP mean on the NFXUP N4?
UP stands for Universal Power: the NFXUP N4 runs on any supply from AC 24-240 V or DC 24-125 V, so a single part number works on both low-voltage and line-voltage systems without a separate transformer.
How do you manually position the NFXUP N4?
Use the supplied 5 mm hex crank (3/16" Allen) to wind the actuator by hand for setup or service.
Is the Belimo NFXUP N4 available from an authorized Belimo distributor?
Yes. ZOT Supply is an authorized Belimo distributor and carries the NFXUP N4. Every unit ships factory new with Belimo's full 5-year warranty and application support.
- Actuator Type:
- Spring-Return (Fail-Safe)
- Torque:
- 90 in-lb
- Control Signal:
- On/Off
- Voltage:
- Universal (24-240 VAC / 24-125 VDC)
- Auxiliary Switch:
- No
- Enclosure:
- NEMA 4X
- Series:
- NFX
