Belimo LF24-S Spring Return Damper Actuator (4Nm, 24V, Open/Close, Aux)

Immediately available

Belimo LF24-S Spring Return Damper Actuator (4Nm, 24V, Open/Close, Aux)

Immediately available

Brand: Belimo

Product type: Damper Actuator

Operating Voltage: 24 VAC/DC

Force / Torque: 4 Nm

Control Signal: 2 Position

Belimo LF24-S fail-safe spring return rotary actuator for HVAC dampers up to approx. 0.8 m², AC/DC 24 V, open/close control, 4 Nm, IP54, 75 s/90°, adjustable rotation limit, supplied/configured with auxiliary switch (S) for end-position feedback.

Product information "Belimo LF24-S Spring Return Damper Actuator (4Nm, 24V, Open/Close, Aux)"

The Belimo LF24-S is a compact fail-safe spring return actuator used to operate HVAC air dampers. During normal operation, the actuator drives the damper to the operating position while tensioning the internal spring. If the 24 V supply is interrupted, the spring automatically returns the damper to the safety position.

It is designed for quick direct mounting using a universal shaft clamp (8–16 mm) and includes an integrated mechanical rotation limiter to set the effective travel. The “-S” version is used when end-position feedback / interlock is required (fire/smoke logic, fan proving, damper status to BMS, etc.).

Applications

AHU and duct air dampers (open/close control)
Outside air / exhaust dampers where fail-safe return is required
Damper end-position status to BMS (open/closed indication)
Interlock logic (fan enable, safety sequencing, shutoff control)

Technical Specifications

Specification	Value
Model	LF24-S
Damper size	Up to approx. 0.8 m²
Supply voltage	AC/DC 24 V
Voltage range	AC 19.2…28.8 V / DC 21.6…28.8 V
Frequency	50/60 Hz
Control	Open/Close (On/Off)
Torque (motor)	4 Nm
Torque (fail-safe)	4 Nm
Running time (motor)	75 s / 90°
Fail-safe time	<20 s @ -20…50°C; <60 s @ -30°C
Angle of rotation	Max. 95° (adjustable 37…100% by mechanical limitation)
Power consumption	5 W (operation); 2.5 W (rest); 7 VA (wire sizing)
Inrush current	5.8 A @ 5 ms
Connection	Cable 1 m, 2 × 0.75 mm²
Parallel operation	Yes
Protection rating	IP54
Protection class	Class III (SELV)
Sound level	50 dB(A)
Shaft clamp	Universal clamp 8…16 mm
Position indication	Mechanical
Service life	Min. 60,000 fail-safe positions
Ambient temperature	-30…50°C
Storage temperature	-40…80°C
Humidity	Max. 95% RH, non-condensing
Maintenance	Maintenance-free
Weight	1.4 kg
Wiring note	Supply from isolating transformer; wire colours: 1=black, 2=red