Watts 9D-M3-1/2 Dual Check Backflow Preventer, 1/2"

Intermediate Atmospheric Vent prevent the reverse flow of hot or cold polluted water from entering into the potable water supply. It consists of a brass body with stainless steel internal parts, integral strainer, and two durable, tight-sealing, rubber check valves. Designed for continuous pressure, non-health hazard applications in smaller supply lines, such as laboratory equipment, processing tanks, sterilizers, dairy equipment, and specifically for boiler feed lines. Minimum Working Pressure: 25 PSI (172kPa), Maximum Working Pressure: 175 PSI (12.1 bar).

• 1/2" female pipe thread union inlet x 1/2" female pipe thread union outlet
• With intermediate atmospheric vent
• Typically installed on boiler feed lines to prevent backflow caused by back siphonage or back pressure
• For systems without antifreeze
• Rust inhibitors or other chemicals which will contaminate the potable water system
• True line-sized construction allows the check modules to open further allowing dirt and debris to pass more freely reducing check fouling
• Stainless steel internal parts
• Maximum flow at low pressure drop
• Furnished with union connections to facilitate removal and replacement for maintenance
• Compact for economy combined with performance
• Design simplicity for easy maintenance
• Can be installed vertically or horizontally
• ASSE & CSA Certified.

Additional Info:

• Specially made for smaller supply lines and ideally suited for laboratory equipment, processing tanks, sterilizers, dairy equipment and similar applications. It is particularly recommended for boiler feed lines to prevent backflow when supply pressure falls below system pressure. Suitable for use on hot or cold water and can be used under continuous pressure. It features a primary check valve utilizing a rubber disc seating against a mating rubber part to ensure tight closing. A secondary check valve utilizes a rubber disc-to-metal seating. In the event of fouling of the downstream check valve, leakage would be vented to atmosphere through the vent port thereby safeguarding the potable water system. Construction is brass body with stainless steel working parts, integral strainer and durable rubber discs. Female union inlet and outlet connections.