The Siemens 331-2974 NO.4 PNEU ACT HESITA SIDE MTG
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.
Technical Specifications
| Pneumatic Model | No. 4 |
| Spring Range | 2-3 / 8-13 psi |
| Ball Joint Connector | NO |
| Clevis | NO |
| Mounting Style | Fixed |
| Pivot | NO |
| Pneumatic Bracket | YES |
| Positioning Relay | NO |
| Stroke | 2-3/8 in |
Normally ships in 7-10 days or sooner… Call 800-323-2739 for details!


