Shield SD-WFD20 Water Flow Switch 2″ (50 mm)
The Shield SD-WFD20 Water Flow Switch (2″ / 50 mm) is a heavy-duty, vane-type mechanical monitoring device designed to detect a continuous water flow within wet pipe fire sprinkler systems and trigger fire alarm signals.
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Description
The Shield SD-WFD20 Water Flow Switch is a precision-engineered safety signaling device built for permanent saddle-mounting on 2-inch (50 mm) steel sprinkler piping (Schedules 10 through 40). Utilizing a flexible polyethylene paddle inserted directly into the pipeline, the switch responds mechanically when water movement matches or exceeds 10 GPM (38 LPM). It features a built-in, field-adjustable pneumatic retard mechanism that delays switch actuation to prevent false alarms caused by localized pressure surges or trapped air. Housed in a rugged, fusion-bonded epoxy-coated aluminum alloy enclosure with tamper-resistant screws, this device includes dual synchronized SPDT switches to activate local notification bells and fire alarm control panels simultaneously.
Features
- Built-In Surge Delay (Retard): Outfitted with an adjustable 0-to-90-second pneumatic delay dial that absorbs transient water pressure spikes to prevent disruptive false alarms.
- Dual SPDT Switching Matrix: Features two independent sets of Single-Pole Double-Throw contacts, enabling simultaneous signaling to the master fire control board and a local audio-visual alarm.
- Heavy-Duty Structural Protection: Enclosed in a NEMA 4 / IP56 die-cast aluminum housing that safeguards internal wiring against dust, humidity, and driving rain in indoor or outdoor installations.
- Streamlined U-Bolt Installation: Designed with a saddle-type mounting profile and durable steel U-bolts for fast, secure clamping directly onto standard scheduled steel piping.
- Flexible Vane Design: Uses a flexible, resilient plastic paddle that accommodates minor pipe imperfections and smoothly restores its neutral position once waterflow halts.
Specifications
- Brand: Shield
- Model: SD-WFD20
- Device Type: Vane-Type Water Flow Switch / Detector
- Nominal Pipe Size: 2 inches (50 mm)
- Mounting Style: U-bolt saddle mount configuration
- Maximum Working Pressure: 450 PSI (31 bar)
- Trigger Flow Rate: 4 to 10 GPM (15 to 38 LPM)
- Surge Protection: Built-in adjustable pneumatic retard delay mechanism (0 to 90 seconds)
- Contact Ratings: Dual SPDT (Form C) micro-switches; 10A at 125/250 VAC, 2.5A at 24 VDC
- Enclosure Rating: NEMA 4 / IP56 rated weather-resistant enclosure
- Enclosure Material: Die-cast aluminum with a corrosion-resistant finish
- Operating Temperature Range: 0ºC to 49ºC (32ºF to 120ºF)
- Tamper Protection: Cover secured by specialized tamper-resistant screws
- Standards Compliance: Designed to meet NFPA 13, 13R, 13D, and NFPA 72 signaling standards
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