
Belimo LM24A-SR – the 24V Modulating Damper Actuator for Precise HVAC Control
, 5 min reading time
, 5 min reading time
The Belimo LM24A-SR is a 24 V modulating damper actuator that delivers 5 Nm of torque with quiet, 1 W energy-saving operation. Built for VAV boxes, zone dampers and compact AHUs, it offers 2–10 V control, manual override and IP54 protection. Contractors value its five-minute installation and maintenance-free design, while facilities teams enjoy precise airflow control that reduces fan energy and enhances comfort.
The Belimo LM24A-SR is a compact, 5 Nm modulating damper actuator that brings seamless 0–10 V positioning and feedback to air-side HVAC control. With a 24 V AC/DC supply, IP54 housing and ultra-low 1 W running load, it delivers the accuracy consultants demand while keeping running costs to an absolute minimum. Whether you are upgrading a variable air-volume (VAV) box or fitting out a packaged air-handling unit, the LM24A-SR provides the dependable movement every modern building needs.
Open spaces demand tight airflow control to stay comfortable across changing occupancies. When paired with pressure-independent VAV boxes, the LM24A-SR maintains exact damper positions, ensuring the required litres-per-second while minimising fan energy. The 2–10 V feedback allows the building-management system (BMS) to verify every stroke in real time, supporting smart analytics and early fault detection.
In apartment blocks using centralised ventilation, each flat often has a fire-rated volume control damper. The LM24A-SR’s slim 0.47 kg body and 150 s stroke keep acoustic breakthrough to a whisper, solving complaints about ‘motor noise’ radiating through ductwork. Maintenance teams appreciate the actuator’s sealed gearbox and overload protection, meaning no routine servicing.
OEMs frequently pre-install the Belimo LM24A-SR on fresh-air and exhaust dampers inside small rooftop or wall-mounted AHUs. Because the actuator draws only 1 W once in motion and 0.4 W at rest, it reduces the panel VA budget and keeps cabinet temperatures low – crucial when electronics share the enclosure.
The LM24A-SR’s high 100 kΩ input impedance places a negligible load on the controller output, while the 1 W power draw translates to roughly 8.8 kWh per year – less than one LED lamp. Over thousands of actuators in a campus, the utility savings add up quickly.
With ±5 % position accuracy and smooth proportional control, temperature swings are reduced, and occupants remain comfortable without unnecessary reheats or chill cycles.
At just 35 dB(A) the actuator moves silently, meeting WELL Building and BCO acoustic guidelines for open-plan workspaces.
The universal shaft clamp fits 6–20 mm spindles, secured with a single screw. An anti-rotation bracket is supplied in the box, so engineers are not forced to fabricate straps on site. Push the manual override, set the blade angle, lock and power up – job done in under five minutes.
Belimo engineers designed the drive train for lifelong lubrication and stall protection. Once fitted, no periodic greasing or recalibration is required, freeing facilities teams for higher-value tasks.
Need auxiliary proof of position for safety circuits? Simply clip on an S2A SPDT switch pack. For analogue master–slave control, add the Z-UIC signal converter to translate 0–10 V to 4–20 mA or vice-versa. Optional form-fit inserts adapt the clamp to 8 mm, 10 mm or 12 mm square shafts for legacy dampers.
Yes, provided it is shielded from direct rain, salt spray and solar radiation, and ambient conditions stay within −30 °C to +50 °C with humidity below 95 % RH.
Absolutely – parallel wiring is supported. Just ensure the combined in-rush and running currents stay within the power supply limits.
No. The actuator is overload protected and stops automatically on reaching each end stop.
About the same as a quiet library. In most ducted installations, the sound cannot be heard beyond the grille.
We hold Belimo LM24A-SR actuators in stock for next-day delivery across the UK. Every unit ships with a two-year manufacturer’s warranty and our technical team is on hand for pre-sale sizing or commissioning advice. Click Add to Basket now or call 01772 284 626 for volume pricing.
Share information and details about these products
Our shop uses cookies. By clicking on Accept you are agreeing to our terms of service and privacy policy.