Watts 9D-3M Atmospheric Vent - Use to prevent backflow

Series 9D Dual Check Valves with Intermediate Atmospheric Vent prevent the reverse flow of hot or cold polluted water from entering into the potable water supply.  Watts 9D consists of a brass body with stainless steel internal parts, integral strainer, and two durable, tight-sealing, rubber check valves. Series 9D is 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.

Watts Series 9D is 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. Series 9D is 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.

Watts 9D Sizes:

1/2" 9D-M3 Backflow Preventer
3/4" 9D-M2 Backflow Preventer

Watts 9D - Features

• 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

The Watts 9D is made of the following materials:

• Forged brass body construction
• Stainless steel internal parts
• Durable, tight seating rubber check valve assemblies
• Pressure — Temperature
  • Temperature Range 33°F – 250°F ( 5°C – 121°C).
  • Maximum Working Pressure:175psi (12 bars)
  • Minimum Required Pressure: 25psi (172 kPa).

IMPORTANT: This valve (Watts 9D) should only be used and properly installed so that spillage of water could not cause damage. To avoid water damage due to valve operation, a drain pipe must be installed. It should terminate approximate 12" (305mm) above a floor drain or through an air gap piped to a floor drain, or other suitable place of disposal. Under no circumstances, should the vent opening or drain line be plugged.

Watts 9D Dual Check Valve with Intermediate Atmospheric Vent  -  Installation Instructions & Field Testing Procedure 

Watts 9D Dual Check Valves with Intermediate Atmospheric Vent  - Specification Sheet (2 - pages)