System Sensor, a part of Honeywell, is a leading manufacturer of fire alarm detection devices, including highly reliable waterflow detectors like the WFD series. These devices are crucial components in wet pipe sprinkler systems, designed to detect the flow of water caused by an activated sprinkler head and then trigger an alarm. Key Features of System Sensor WFD Waterflow Detectors: Vane-Type Design: The WFD series utilizes a paddle or vane that is inserted into the pipe. When water flows above a certain rate, it deflects the vane, which in turn activates the alarm switch. Mechanical Time Delay (Retard): A key feature of the WFD (and WFDT/WFDTNA models) is the built-in mechanical time delay. This adjustable delay (typically 0-90 seconds, often factory set around 25-30 seconds) helps prevent false alarms caused by pressure surges, sudden changes in water pressure, or trapped air in the sprinkler system. The delay mechanism is sealed to prevent contamination. Dual SPDT (Form C) Synchronized Switches: The WFD series features two sets of Single Pole Double Throw (SPDT) contacts. These switches operate synchronously, allowing for connection to both a fire alarm control panel and a local bell or horn/strobe, ensuring comprehensive alarm activation. Rugged, NEMA 4-Rated Enclosure: The detectors are housed in a durable, robust enclosure (often metal with red epoxy paint or a damage-resistant non-metallic cover in some variants) that is NEMA 4 rated, making them suitable for both indoor and outdoor use. Wide Temperature Range: They are designed to operate across a reasonable temperature range, typically from 32°F to 120°F (0°C to 49°C), with some models extending to 150°F (66°C). Compatibility: WFD detectors are compatible with Schedule 10 through 40 steel pipes, typically ranging in sizes from 2 inches to 8 inches. Specific models might also support 1' NPT and CPVC connections for residential or branch line signaling. They can be mounted in vertical (upflow) or horizontal positions. Field-Replaceable Components: The retard mechanism and SPDT switches are designed to be field-replaceable, simplifying maintenance and reducing downtime. Tamper-Resistant: Equipped with tamper-resistant cover screws to prevent unauthorized access. An optional cover tamper switch kit is also available. Visual Switch Activation: Some models offer visual indication of switch activation, aiding in installation and troubleshooting. Certifications: UL Listed, ULC, FM Approved, CSFM, MEA Approved, ensuring they meet rigorous safety and performance standards for fire protection applications. Typical Specifications: Static Pressure Rating: Up to 250 PSI (some models may be rated higher, e.g., 450 PSI). Triggering Threshold Bandwidth (Flow Rate): Typically 4 to 10 GPM (Gallons Per Minute). This means they activate when flow is 10 GPM or more, and will not activate below 4 GPM. Maximum Surge: 18 Feet Per Second (FPS). Contact Ratings: Usually 10.0 A @ 125/250 VAC, 2.5 A @ 6/12/24 VDC. Conduit Entrances: Two openings (often one open, one knockout) for standard 1/2' conduit. Applications: System Sensor WFD waterflow detectors are specifically designed for and primarily used in: Wet Pipe Sprinkler Systems: This is their primary application, detecting water flow when a sprinkler head activates due to fire. Fire Alarm Systems: They provide an alarm signal to the fire alarm control panel, initiating evacuation procedures and notifying authorities. Residential and Commercial Buildings: Essential for fire safety in a wide variety of structures. Important Installation Notes (from manuals): Wet-Pipe Systems ONLY: WFD detectors are only for wet-pipe systems. Do NOT use them in dry pipe, deluge, or preaction systems, as the sudden inrush of water can damage the vane. Mounting Location: Install on a clear pipe span, at least 6 inches from any fittings that change water direction/flow, and no closer than 24 inches from a valve or drain. Orientation: On horizontal runs, mount on the top or side of the pipe; never upside down to prevent condensation issues. For vertical flow, mount on pipes where water flows upward. Direction of Flow: Crucially, ensure the direction-of-flow arrow on the detector matches the actual flow direction in the pipe. You can avail this at namokar Enterprises Hauz Qazi