Xylem FS1-J High Sensitivity Liquid Flow Switch 1/2" BSPT

The Xylem (McDonnell & Miller) FS1-J is a high sensitivity liquid flow switch designed for precise flow monitoring in HVAC, hydronic, and industrial applications. This independently mounted flow sensing device makes or breaks an electrical circuit when liquid flow stops or starts, providing reliable protection and control.

Key Features:

• 1/2" BSPT (British Standard Pipe Tapered) threaded connection for easy integration
• Single Pole Double Throw (SPDT) snap-acting switch for versatile circuit control
• In-line configuration eliminates the need for pipe tees, simplifying installation
• High sensitivity design ideal for moderate to low flow rate applications
• Sealed switch compartment protects electrical components from liquid exposure
• Adjustable sensitivity screw allows easy flow adjustment for precise control
• Compact, rugged construction withstands demanding industrial environments

Specifications:

• Connection Size: 1/2" BSPT threads
• Switch Type: Single Pole Double Throw (SPDT)
• Maximum Operating Pressure: 100 PSI (7 kg/cm²)
• Temperature Range: 32°F to 225°F (0°C to 107°C)
• Manufacturer Part Number: 172829 / 113550

Applications:

• Air conditioning and heating systems
• Hydronic heating systems
• Water flow monitoring
• Fuel oil systems
• Process control with viscous liquids and oils
• Steam and hot water boilers with cold water feed

The FS1-J provides continuous protection against low water conditions and satisfies pump control needs for commercial and industrial steam boilers, making it an essential component for reliable flow control in critical applications.