Xylem FS4-3S General Purpose Liquid Flow Switch Stainless Steel 1" NPT

The Xylem McDonnell & Miller FS4-3S (Part #114641) is a general-purpose liquid flow switch designed for commercial and industrial HVAC, boiler, and plumbing applications. This flow switch features a premium stainless steel body with Monel bellows construction for superior corrosion resistance and durability in demanding environments.

Key Features:

• 1" NPT threaded connection for easy installation in standard piping systems
• Single-pole, double-throw (SPDT) switch mechanism for versatile control options
• Includes four stainless steel paddles: 1", 2", 3", and 6" lengths for different pipe sizes and flow conditions
• Stainless steel body with Monel bellows for exceptional corrosion resistance
• Maximum pressure rating of 160 PSI
• Maximum temperature rating of 300°F (149°C)
• Adjustable sensitivity screw for precise flow rate adjustment
• Universal design compatible with flow rates from 6 to 10.2 GPM in 1" pipe
• Two electrical knockouts allow convenient wiring from either end

Applications:

This flow switch is ideal for starting or stopping electrically operated equipment including signal lights, alarms, motors, automatic burners, metering devices, pumps, and other fluid control systems. The FS4-3S serves as a reliable replacement for flow switches from Johnson/Penn, Potter/Taco, Watts, Hydro-level, and other manufacturers. Its robust stainless steel construction makes it particularly well-suited for applications involving corrosive liquids or harsh operating conditions where standard brass flow switches may not provide adequate service life.