Siemens Building Technology 274-05921 3-Inch 2-Way Normally Open Flanged Valve Actuator Assembly with Stainless Steel Trim

The Siemens Building Technology 274-05921 is a complete 3-inch, 2-way normally open (NO) globe valve and actuator assembly from the Flowrite™ 599 Series, designed for precise proportional flow control in commercial and industrial HVAC hydronic systems. This factory-assembled unit pairs the 599-05921 valve body with the SKD62U electrohydraulic spring-return actuator, providing reliable, fail-safe operation in a single ready-to-install package.

Key Features:

• Pipe Size: 3-inch flanged connection
• Valve Type: 2-way, normally open (NO) fail-safe position
• Trim Material: Stainless steel (S.S.) for corrosion resistance and durability
• Flow Characteristic: Equal percentage for precise modulating control
• Cv Rating: 100 — high flow capacity for large systems
• Close-Off Pressure: 25 PSI
• Power Supply: 24 VAC electric
• Control Signal: 0–10 VDC or 4–20 mA proportional input
• Feedback Signal: 0–10 VDC or 4–20 mA position feedback
• Actuator: SKD62U spring-return electrohydraulic actuator — returns valve to normally open position on power loss
• NEMA Rating: NEMA 1 (indoor use)
• Actuator Listing: UL Listed

The SKD62U actuator provides spring-return fail-safe action, meaning the valve automatically returns to its normally open position in the event of a power failure, protecting connected systems from over-temperature or flow-starved conditions. The assembly accepts standard 0–10 VDC or 4–20 mA control signals and provides matching position feedback, making it fully compatible with most building automation and direct digital control (DDC) systems.

Typical applications include chilled water and hot water modulating control for air handling units, fan coil units, and central plant equipment. The stainless steel trim makes this assembly well-suited for systems with treated water, glycol solutions, or mildly corrosive media. Valve body part number: 599-05921. Alternate part number: 27405921.