System Sensor WFD40N

The System Sensor WFD40N is a 4-inch waterflow detector designed for large-diameter fire suppression systems to monitor water movement in sprinkler pipelines. This vane-type detector automatically signals the fire alarm control panel when water flows through 4-inch diameter steel pipe, triggering an immediate alarm condition with dual synchronized relays for reliable notification and system coordination.

Key Features

• 4-inch pipe compatibility for large commercial and industrial sprinkler systems with 450 PSI maximum pressure rating
• Two sets of SPDT (Form C) synchronized switches providing dual-channel alarm signaling
• NEMA 4-rated enclosure constructed for durability in demanding industrial environments
• Low 4 to 10 GPM alarm threshold prevents false alarms during normal system operation

Technical Specifications

• Operating Voltage: 15–32 VDC for addressable alarm panel integration
• Operating Temperature Range: 32°F to 150°F (0°C to 66°C)
• Contact Ratings: 10 A @ 125/250 VAC and 2.5 A @ 24 VDC
• Standby Current: Less than 250 µA; Alarm Current: 5–7 mA
• Pipe Compatibility: 4-inch steel water pipe, Schedule 7 through 40; vertical or horizontal mounting
• Dimensions: 2.6 inches H × 3.5 inches W × 6.7 inches D
• Humidity Range: 10%–93% non-condensing

Certifications

• UL Listed for fire protection service
• FM Approved for automatic detection and signaling
• NFPA 72 compliant fire alarm system component