Belimo SFA-S2 Spring Return Damper Actuator (20Nm, 24–240V, Open/Close, 2x Aux)

Immediately available

Belimo SFA-S2 Spring Return Damper Actuator (20Nm, 24–240V, Open/Close, 2x Aux)

Immediately available

Brand: Belimo

Product type: Damper Actuator

Operating Voltage: AC 24...240 V / DC 24...125 V

Force / Torque: 20 Nm

Control Signal: 2 Position

Belimo SFA-S2 fail-safe spring return rotary actuator for HVAC dampers up to approx. 4 m²; AC 24–240 V / DC 24–125 V, open/close, 20 Nm, IP54 / NEMA 2, 75 s/90°, with 2x SPDT auxiliary switches (1 fixed 10%, 1 adjustable 11–100%)

Product information "Belimo SFA-S2 Spring Return Damper Actuator (20Nm, 24–240V, Open/Close, 2x Aux)"

The Belimo SFA-S2 is a heavy-duty fail-safe spring return actuator for controlling HVAC air dampers in technical building installations. It uses a universal power supply module that accepts AC 24…240 V and DC 24…125 V, reducing the need to stock multiple voltage variants.

In normal operation, the actuator drives the damper to the operating position while tensioning the return spring. When power is interrupted, the spring returns the damper to the fail-safe position. It supports simple direct mounting on the damper shaft with a universal clamp and includes a hand-crank manual override with a locking switch for commissioning and maintenance.

Applications

AHU fresh / return / exhaust air dampers requiring fail-safe return
Smoke extract / safety dampers where a defined fail-safe position is required (application-dependent)
Large dampers up to approx. 4 m² requiring 20 Nm torque
BMS interlocks and damper proof using integrated auxiliary switches

Technical data

Specification	Value
Model	SFA-S2
Damper size	Up to approx. 4 m²
Supply	AC 24–240 V / DC 24–125 V
Frequency	50/60 Hz
Voltage range	AC 19.2–264 V / DC 21.6–137.5 V
Control	Open/Close
Torque (motor)	20 Nm
Torque (fail-safe)	20 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 end stop)
Power (operation / rest)	7 W / 3.5 W
Wire sizing	18 VA
Connection supply/control	Cable 1 m, 2 x 0.75 mm²
Aux switches	2x SPDT (1x 10% fixed / 1x 11–100% adjustable)
Aux switch rating	1 mA–3 A (0.5 A inductive), DC 5 V–AC 250 V
Aux switch cable	Cable 1 m, 6 x 0.75 mm²
Protection	IP54; NEMA 2; UL Type 2
Insulation	Class II (reinforced)
Manual override	Hand crank + locking switch
Shaft clamp	Universal 10…25.4 mm
Sound level	45 dB(A)
Service life	Min. 60,000 fail-safe positions
Ambient	-30…50°C; max 95% RH non-condensing
Storage	-40…80°C
Weight	2.3 kg
Hygiene	VDI 6022 Part 1 / SWKI VA 104-01