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SiemensLinear Actuators

Siemens Pneumatic Actuator: Rotary, 8 psi to 13 psi Spring Range, Extended Shaft Mounting

The Siemens Pneumatic Actuator: Rotary (SKU 331-4821, MPN 331-4821) is a linear actuator with a pivot connection, designed for fire and smoke applications. It features an 8 psi to 13 psi spring range, extended shaft…

SKU 3G-OTH-67679

Also listed as: 3314821 · 331 4821

Brand
Siemens
Item
Pneumatic Actuator: Rotary, 8 psi to 13 psi Spring Range, Extended Shaft Mounting
Category
Linear Actuators
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Technical Specifications

Siemens
Manufacturer Part Number
331-4821
Type
Extended Shaft Mounting
Stroke
2 3/4 in
Spring Range
8 psi to 13 psi
Actuator Connection
Pivot
Positioner Included
No
For Fire/Smoke Applications
Yes

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Siemens Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

The Siemens Pneumatic Actuator: Rotary (SKU 331-4821, MPN 331-4821) is a linear actuator with a pivot connection, designed for fire and smoke applications. It features an 8 psi to 13 psi spring range, extended shaft mounting, and a 2 3/4 in stroke. No positioner is included.

Frequently Asked Questions

What is the Siemens 331-4821 pneumatic actuator used for?

The Siemens 331-4821 pneumatic actuator is designed for fire and smoke applications, such as controlling dampers in HVAC systems. Its pivot connection and extended shaft mounting suit rotary damper installations. With an 8 psi to 13 psi spring range and 2 3/4 in stroke, it provides reliable fail-safe positioning in life-safety systems.

What are the specifications of the Siemens 331-4821 pneumatic actuator?

The Siemens 331-4821 is a linear actuator with a pivot connection, extended shaft mounting, and a 2 3/4 in stroke. It operates with an 8 psi to 13 psi spring range and is intended for fire/smoke applications. No positioner is included. The actuator is manufactured by Siemens under MPN 331-4821.

Where to buy the Siemens 331-4821 pneumatic actuator worldwide?

You can source the Siemens 331-4821 pneumatic actuator through 3G Electric, a global industrial equipment distributor. We handle full logistics, customs clearance, and delivery to worldwide destinations. Contact us for availability and lead time; we supply genuine Siemens components for fire and smoke damper applications.

How to install the Siemens 331-4821 pneumatic actuator?

Install the Siemens 331-4821 by mounting it with the extended shaft bracket to the damper pivot. Connect pneumatic supply within the 8 psi to 13 psi spring range. Ensure the 2 3/4 in stroke aligns with damper travel. No positioner is included, so external control is required. Follow Siemens guidelines for fire/smoke actuator installation.

Used in

Common applications for Siemens
District cooling plants — LME73 + RWF55 for condenser-water modulation
Inflight catering and food-processing steam boilers — LMG22 with SQN90 air-fuel cross-damper
Hospital steam-plant redundancy — LME41 with QRA2 UV flame detection for dual-fuel boilers
Semiconductor fab process heat — LME23 and SKP55 gas valves on hot-oil heater skids
Container-terminal reefer-deck heating — LMG22 retrofit onto legacy burner racks

Siemens Products

3G Electric supplies Siemens linear actuators. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

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SIEMENS Electric Actuator: Manual Return, 2.3 sec Cycle Time, 179 in-lb Torque, 90° Stroke Degree (MPN 546-00437B)
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