The Belimo LMX24-MFT is a compact non-spring-return damper actuator delivering 45 in-lb [5 Nm] of torque with field-programmable MFT control that ships set for 2-10 VDC by default on AC/DC 24 V power. It direct-couples to round or square damper shafts from 1/4 in. to 5/8 in. (up to 3/4 in. with an accessory clamp) and is non-fail-safe, with no spring return, making it part of Belimo's configurable LMX platform for small to mid-size commercial HVAC dampers.
Specifications sourced from the official Belimo LMX24-MFT technical data sheet (rev 2026-06-08).
Overview
Belimo LM-Series actuators are compact non-spring-return drives for small and mid-size commercial HVAC dampers — they position the damper under power and have no spring-return fail-safe function. The LMX24-MFT produces 45 in-lb [5 Nm] and mounts directly to round or square damper shafts from 1/4 in. to 5/8 in. (up to 3/4 in. with an accessory clamp). It ships set for 2-10 VDC modulating control — the same behavior as the SR model — while Multi-Function Technology lets you field-select other signals, ranges and feedback under one part number.
Best for
- Modulating control with field-selectable signal (2-10 VDC default)
- Small to mid-size damper and louver positioning (45 in-lb)
- Direct shaft mount, 1/4-5/8 in. (to 3/4 in. with accessory clamp)
Key Features
Non-Spring-Return Design
No fail-safe spring return. Belimo does not publish a defined position on loss of power for this model; specify a spring-return actuator where a fail-safe position is required.
45 in-lb Torque
Sized for small and mid-size dampers; direct-couples to round or square damper shafts from 1/4 in. to 5/8 in. (up to 3/4 in. with an accessory clamp).
MFT — 2-10 VDC by Default
Ships set for 2-10 VDC modulating control. Field-select other signals and ranges under one part number.
cULus Listed & Quiet
cULus listed, ISO 9001 built, UL 2043 plenum-rated for long, maintenance-free service.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Belimo |
| Part Number | LMX24-MFT |
| Actuator Type | Non-Spring-Return (Non Fail-Safe) Damper Actuator |
| Nominal Voltage | AC/DC 24 V |
| Nominal Frequency | 50/60 Hz |
| Power Consumption (Running) | 2.5 W |
| Transformer Sizing | 5 VA |
| Torque | 45 in-lb [5 Nm] |
| Control Signal | Modulating, field-programmable (MFT) — ships set for 2-10 VDC by default |
| Selectable Modes | 2-10 VDC (default), variable VDC, On/Off, Floating Point, PWM |
| Position Feedback (U) | 2-10 VDC default (max. 0.5 mA) |
| Shaft Range | 1/4 in. to 5/8 in. (to 3/4 in. with accessory clamp) |
| Angle of Rotation | Max. 95° (adjustable mechanical stop) |
| Running Time (Motor) | 150 s / 90° |
| Variable Running Time | 30-150 s |
| Behavior on Power Loss | Non fail-safe — no fail-safe spring return function |
| Manual Override | External push button |
| Direction of Motion | Selectable with 0/1 switch |
| Electrical Connection | 18 AWG plenum cable, 3 ft [1 m], 1/2 in. NPT conduit connector |
| Overload Protection | Electronic, full 0-95° rotation |
| Power Source | UL Class 2 Supply |
| Enclosure Rating | NEMA 2 / UL Type 2 |
| Ingress Protection | IP54 — stated on the datasheet for the cable and conduit connector |
| 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 | 0.97 lb [0.44 kg] |
| Warranty | 5 Years |
Documentation
Related Products
Accessories & Mounting
Common Belimo accessories for mounting, linkage, signaling and powering the LMX24-MFT, drawn from the actuator datasheet. All are stocked by ZOT Supply as an authorized Belimo distributor.
Mounting & Linkage
Electrical Add-Ons
Enclosures & Weather Shields
Frequently Asked Questions
What is the Belimo LMX24-MFT?
The Belimo LMX24-MFT is a compact non-spring-return (non-fail-safe) damper actuator for commercial HVAC. It produces 45 in-lb [5 Nm] of torque, uses field-programmable MFT control (set for 2-10 VDC by default) on AC/DC 24 V power. It is non-fail-safe: Belimo does not publish a defined position on loss of power for this model. Its housing is rated NEMA 2.
Is the LMX24-MFT a spring-return (fail-safe) actuator?
No. The LMX24-MFT is non-spring-return: it has no fail-safe spring, so it will not drive to a predetermined position when power is lost. Where a defined position on power loss is required, select a spring-return actuator sized to the damper manufacturer's specifications.
What happens to the LMX24-MFT when power is lost?
There is no spring return, so the actuator does not drive itself to a fail-safe position. Belimo's datasheet for this model does not publish a defined power-loss position; if your sequence depends on a specific position during a power failure, specify a spring-return actuator.
What shaft sizes does the LMX24-MFT fit?
It direct-couples to round or square damper shafts from 1/4 in. to 5/8 in. (up to 3/4 in. with an accessory clamp) using its universal clamp.
What control signal does the LMX24-MFT use?
It uses field-programmable MFT control (set for 2-10 VDC by default). Because it is MFT, you can field-select other modes (variable VDC, on/off, floating point, PWM) without changing the part number.
What is the running time of the LMX24-MFT?
Motor running time is 150 s / 90°. It is field-programmable from 30 to 150 seconds via MFT.
Is the LMX24-MFT the same as the SR (2-10 VDC) version?
Not identical. Belimo assigns the default MFT parameters for 2-10 V applications during manufacturing, so the unit ships set for 2-10 VDC modulating control, and MFT lets you field-select other signals and ranges under one part number. The published specifications still differ: LMX24-MFT and LMX24-SR differ on running time 150 s / 90° vs 95 s / 90°; variable running time 30-150 s vs 35, 45, 60, 150 s; running power 2.5 W vs 1.5 W; transformer sizing 5 VA vs 3 VA. Verify the exact specifications before substituting.
What is the difference between the Belimo LMX24-MFT and the LMB24-MFT?
Both are non-spring-return actuators of the same torque class. Their published specifications are not identical: LMX24-MFT and LMB24-MFT differ on running time 150 s / 90° vs 95 s / 90°; variable running time 30-150 s vs 35-150 s; weight 0.97 lb vs 1.2 lb. Both datasheets state NEMA 2 / IP54 protection and the same electrical connection. Verify the exact control, running time, electrical, enclosure and mounting requirements before substituting one for the other.
Is the Belimo LMX24-MFT available from an authorized Belimo distributor?
Yes. ZOT Supply is an authorized Belimo distributor and carries the LMX24-MFT. Every unit ships factory new with Belimo's full 5-year warranty and application support.
- Actuator Type:
- Non-Fail-Safe
- Torque:
- 45 in-lb
- Control Signal:
- Programmable (MFT)
- Voltage:
- 24 VAC/DC
- Auxiliary Switch:
- No
- Series:
- LM
- Feedback Signal:
- 2-10 VDC
