System Sensor WFD25N 2.5″ Waterflow Detector

The System Sensor WFD25N Waterflow Detector is a vane-type waterflow switch designed to monitor 2-1/2-inch steel wet sprinkler piping in commercial and industrial fire protection systems. Engineered for dependable performance, the System Sensor WFD25N detects sustained water flow caused by sprinkler activation and initiates alarm notification through connected fire alarm control panels. Therefore, it provides reliable waterflow monitoring while helping ensure rapid emergency response during fire events.

System Sensor WFD25N Function

The System Sensor WFD25N is designed to detect water movement within a wet-pipe sprinkler system using a mechanical vane inserted into the pipeline. As a result, when sprinkler operation produces water flow within the specified activation range, the detector activates its internal switches to transmit an alarm signal to the fire alarm system. In addition, the device incorporates a field-adjustable pneumatic retard mechanism that helps eliminate nuisance alarms caused by pressure surges or trapped air.

Designed for 2-1/2-Inch Wet Sprinkler Systems

The WFD25N is specifically engineered for installation on 2-1/2-inch Schedule 7 through Schedule 40 steel pipe. Consequently, it provides accurate waterflow detection for a wide range of commercial fire sprinkler applications. Moreover, the detector can be mounted on either horizontal or vertical piping, providing installation flexibility for new construction and retrofit projects.

Adjustable Pneumatic Time Delay

The System Sensor WFD25N features a field-adjustable pneumatic retard mechanism with an adjustment range of approximately 0 to 90 seconds. Therefore, installers can configure the detector to minimize false alarms caused by water hammer or temporary pressure fluctuations while maintaining rapid response to actual sprinkler activation. Furthermore, the sealed delay mechanism is protected from dust and environmental contaminants for long-term reliability.

Dual SPDT Alarm Contacts

The WFD25N includes two synchronized SPDT (Form C) switches, allowing simultaneous activation of multiple circuits. As a result, one contact can report alarm conditions to the fire alarm control panel while the second contact operates local bells, horns, supervisory equipment, or building automation systems. Additionally, the synchronized switch design simplifies system integration and wiring.

Rugged NEMA 4 Construction

The System Sensor WFD25N features a durable NEMA 4-rated enclosure designed for both indoor and outdoor installations. Consequently, the detector provides dependable operation in demanding environmental conditions while resisting moisture, corrosion, and physical damage. The enclosure also incorporates tamper-resistant cover screws and an optional cover tamper switch for enhanced security.

Technical Specifications

• Model: WFD25N
• Type: Vane-Type Waterflow Detector
• Manufacturer: System Sensor
• Pipe Size: 2-1/2 Inches
• Compatible Pipe: Schedule 7–40 Steel Pipe
• Detection Method: Mechanical Vane
• Triggering Threshold: 4–10 GPM
• Static Pressure Rating: 450 PSI
• Maximum Surge Velocity: 18 ft/sec
• Time Delay: Adjustable Pneumatic Delay (Approx. 0–90 Seconds)
• Contact Configuration: Two SPDT (Form C) Switches
• Contact Rating:
  • 10A, 1/2 HP @ 125/250 VAC
  • 2.5A @ 6/12/24 VDC
• Enclosure Rating: NEMA 4
• Mounting: Horizontal or Vertical Pipe
• Conduit Openings: Two 1/2-Inch
• Operating Temperature: 32°F to 150°F (0°C to 66°C)
• Standards: UL Listed, FM Approved
• Application: Wet-Pipe Fire Sprinkler Systems

Applications

The System Sensor WFD25N Waterflow Detector is ideal for:

• Wet-pipe fire sprinkler systems
• Commercial office buildings
• Educational facilities
• Healthcare facilities
• Industrial plants
• Warehouses
• Retail centers
• Hotels and hospitality properties
• Government buildings
• Institutional fire protection systems

Reliable Waterflow Detection Solution

The System Sensor WFD25N Waterflow Detector combines accurate vane-type waterflow sensing, adjustable pneumatic delay, dual SPDT contacts, and a rugged NEMA 4 enclosure in a dependable fire protection device. Overall, it enhances sprinkler system monitoring by providing fast, reliable waterflow detection while minimizing false alarms and simplifying integration with commercial fire alarm systems.

WFD25N