Could you please explain what a "pressure vacuum breaker" is?
Kind of sounds like an oxy moron to me.
A vacuum breaker on yard hydrants and/or yard sprinkler systems are
used to prevent back syphonage under certain conditions and they are
atmospheric vacuum breakers.
welcome to the world of cross-contamination control. A PVB is a type of
back-flow preventer. A step up from an atmospheric vacuum breaker but a step
below a dual-check or reduced-pressure backflow device.