Pressure Vacuum Breaker Backflow Prevention Device Assembly – Backflow Backsiphonage
If a backflow backsiphonage were to occur in the inlet or supply piping and the downstream and upstream shut-off valves were open, the check valve would close tight if operating properly preventing non-potable from siphoning into the potable water system. With the check valve closed, positive pressure remains in the area downstream of the check valve keeping the air inlet closed. The PVB is providing protection during a backsiphonage condition since the check valve closed drip tight. Because the check valve may fail, a certified tester should test the PVB at least annually.
