The Watts Series 957NRPDA 8 inch Reduced Pressure Detector Assembly with OSY Shutoff Valves is designed to protect potable water systems from contamination due to back-siphonage and backpressure in health hazard applications. This backflow preventer also monitors unauthorized water use from fire protection systems.

WARNING: It is illegal to use this product in any plumbing system providing water for human consumption, such as drinking or dishwashing, in the United States. Before installing standard material product, consult your local water authority, building and plumbing codes.

Construction & Features

• Features an extremely compact design that is 70% lighter than traditional models, allowing for use in smaller enclosures.
• The assembly consists of a 304 (Schedule 40) stainless steel housing and sleeve with groove end connections for integral pipeline adjustment.
• Two independent torsion spring check modules with patented torsion spring checks provide the lowest pressure loss and drip-tight closure against reverse flow.
• Reversible silicone or EPDM check disc rubber ensures unmatched ease of serviceability.
• Includes a bottom-mounted cast stainless steel relief valve, designed for corrosion resistance.
• The bypass line is furnished with a cubic feet per minute meter to detect underground leaks and unauthorized water use from the fire sprinkler system.
• Equipped with UL Classified and FM Approved outside stem and yoke (OSY) resilient seated gate valves for reliable shutoff.

Advanced Flood Detection

• A flood sensor with SentryPlus Alert® technology is integrated on the relief valve to detect excessive water discharges.
• The sensor relays signals to facility personnel for corrective action, limiting flooding and costly damage.
• For active flood alerts, an add-on sensor connection kit is required to activate the sensor's communication capabilities.
• Connection kit options include compatibility with BMS, cellular communication, or the Sensor Control Monitor for integration with BAS via RS-485 Modbus or the Nexa® platform via Wi-Fi.
• Note: Use of the flood sensor does not replace the need to comply with all required instructions, codes, and regulations related to installation, operation, and maintenance of this product, including the need to provide proper drainage in the event of a discharge.