This Watts Series LF9D dual check valve backflow preventer with an intermediate atmospheric vent is designed for non-health hazard applications in smaller supply lines. It effectively prevents the reverse flow of hot or cold polluted water from entering the potable water supply, particularly suited for boiler feed lines, laboratory equipment, and sterilizers.

Construction & Operation

• Features a lead free forged brass body with stainless steel internal parts and an integral strainer.
• Incorporates two durable, tight-seating rubber check valve backflow preventers.
• The primary check valve uses a rubber disc seating against a rubber part for tight closure.
• The secondary check valve features rubber disc-to-metal seating.
• In the event of downstream check valve fouling, leakage is vented to atmosphere through the vent port, safeguarding the potable water system.
• Can be installed vertically or horizontally.

Key Features

• Lead Free construction ensures the wetted surface contains less than 0.25% lead by weight.
• True line-sized construction allows check modules to open further, reducing fouling from dirt and debris.
• Provides maximum flow at low pressure drop.
• Compact design combines economy with performance and features design simplicity for easy maintenance.
• Union solder connections facilitate easy removal and replacement for maintenance.

Safety Warning: This valve should only be used and properly installed so that spillage of water will not cause damage. A drain pipe must be installed, terminating approximately 12 inches (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.