The Belimo LMQB24-MFT is a compact non-spring-return damper actuator delivering 35 in-lb [4 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 holds its last position on loss of power (it is non-fail-safe, with no spring return), making it a proven member of the LMB platform for small to mid-size commercial HVAC dampers. A "Q" quick-running motor drives 90° in just 2.5 seconds.
Specifications sourced from the official Belimo LMQB24-MFT technical data sheet (rev 2025-10-06).
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 hold the last commanded position when power is removed (there is no spring-return fail-safe). The LMQB24-MFT produces 35 in-lb [4 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). Its quick-running motor completes 90° in about 2.5 seconds. 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 (35 in-lb)
- Direct shaft mount, 1/4-5/8 in. (to 3/4 in. with accessory clamp)
- Fast / high-cycle response (2.5-second run time)
Key Features
Non-Spring-Return Design
Holds the last commanded position when power is removed (non-fail-safe). Lower cost and power draw than a spring-return actuator where fail-safe operation is not required.
35 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.
Quick 2.5-Second Run Time
A "Q" quick-running motor drives 90° in about 2.5 seconds for fast, high-cycle response.
cULus Listed & Quiet
Double-insulated (Class 2), cULus listed, ISO 9001 built, UL 2043 plenum-rated for long, maintenance-free service.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Belimo |
| Part Number | LMQB24-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) | 13 W |
| Transformer Sizing | 23 VA Inrush current 20.0 A @ 5 ms Overload Protection electronic throughout 0...95° rotation |
| Torque | 35 in-lb [4 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) | 2.5 s / 90° Running time motor variable 2.5...10 s Noise level, motor 52 dB |
| Behavior on Power Loss | Holds last position (non-spring-return) |
| Manual Override | External push button (self-locking gear) |
| Direction of Motion | Selectable with 0/1 switch |
| 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 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 | 2.4 lb [1.1 kg] |
| Warranty | 5 Years |
Documentation
Related Products
Accessories & Mounting
Common Belimo accessories for mounting, linkage, signaling and powering the LMQB24-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 LMQB24-MFT?
The Belimo LMQB24-MFT is a compact non-spring-return (non-fail-safe) damper actuator for commercial HVAC. It produces 35 in-lb [4 Nm] of torque, uses field-programmable MFT control (set for 2-10 VDC by default) on AC/DC 24 V power, and holds its last position on loss of power. Its housing is rated NEMA 2.
Is the LMQB24-MFT a spring-return (fail-safe) actuator?
No. The LMQB24-MFT is non-spring-return: when power is lost it holds its last commanded position rather than driving to a fail-safe position. If you need fail-safe operation, choose a spring-return Belimo LF-Series actuator instead.
What happens to the LMQB24-MFT when power is lost?
It stays put. A non-spring-return actuator maintains its last position when power is removed and resumes from there when power returns.
What shaft sizes does the LMQB24-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 LMQB24-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 LMQB24-MFT?
Motor running time is about 2.5 s / 90° Running time motor variable 2.5...10 s Noise level, motor 52 dB for 90 degrees of travel. The 'Q' quick-running design suits fast or high-cycle damper applications.
Is the LMQB24-MFT the same as the SR (2-10 VDC) version?
Functionally yes — it ships set for 2-10 VDC modulating control, identical to the SR model. MFT simply lets you field-select other signals and ranges, so one part number covers many specifications.
Is the Belimo LMQB24-MFT available from an authorized Belimo distributor?
Yes. ZOT Supply is an authorized Belimo distributor and carries the LMQB24-MFT. Every unit ships factory new with Belimo's full 5-year warranty and application support.
- Actuator Type:
- Non-Spring-Return
- Torque:
- 35 in-lb
- Control Signal:
- Programmable (MFT)
- Voltage:
- 24 VAC/DC
- Auxiliary Switch:
- No
- Series:
- LMB
- Feedback Signal:
- 2-10 VDC
