The brass atmospheric vacuum breaker (AVB) is a simple way to protect your drinking water system from accidental contamination. Install an atmospheric vacuum breaker at least 6 in. above all downstream piping and components. It prevents backflow by opening when the irrigation system is on and closing when it is off. The inlet and outlet are 3/4-in. female pipe thread (FPT). The brass construction ensures durability. The serviceable internal components, including O-rings, spring, and “poppet,” are available in a repair kit.
Note that manual and automatic anti-siphon valves combine a valve and an atmospheric vacuum breaker in one unit, which may be a good alternative in many cases. Backflow prevention and cross-connection rules vary from city to city, so please verify your specific local code. For outdoor irrigation use with cold water only.
WARNING: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to: www.P65Warnings.ca.gov.