Use of vacuum breaker 1

Are you sure it's not an air vent?

I would put one in a closed loop system to allow draining of the system without too much operator involvement. I would spec an air/vacuum valve wich would serve to let air out as well during filling and normal operation.

Hope this was of some help....

bob

Vacuum breakers may be used to mitigate waterhammer transient pressures, particularly on pump stop. A negative pressure wave can be tansmitted along the pipe that will cause check valve slam and other effects. the vaccum breaker allows air into the system and reduces the magnitude of the pressure wave. There should however be an air vent to allow thw air to be removed when the system is pressurized.