331-2974 | Damper Actuator, Pneu No 4, 2-3/8" Stroke, Unit Ventilator Hesitation Model | Siemens

This 331 Number 4 Pneumatic Damper Actuator has a 2 3/8" stroke for unit ventilators and is a rugged, metal-fabricated device that provides gradual or positive actuation of HVAC and fire/smoke dampers. This hesitation model actuator has a nominal spring range of 2 to 3 and 8 to 13 psi, is fixed bracket mounted and provides minimum ventilation without separate damper/actuator. This actuator has an air connection of 1/8" NPT female with a dual barb elbow fitting for 1/4" OD tubing.