The Model 720 and 720A are pressure vacuum breaker assemblies. Production began approximately 1975 under the SMR name. Around 1978 it was sold to the Neptune Meter Co. In 1984 Wilkins regulator bought the rights to produce this assembly. The assembly is of bronze body construction. The check spring is contained when the bonnet is removed. The check seat is cast in the body and is not replaceable. The A designation in the model number refers to a design change in the air inlet parts. Both models will accept the new “A” design. The air inlet utilizes a rubber fold to exert the pressure for the air inlet loading. There is no spring on the air inlet. Before 1994 the test cocks used were a specially designed needle valve that required turning of the test cock to operate. In 1994 a standard ball valve type test cock was utilized. In 2010 the test cocks were moved from the body to the ball valve.
- Maximum working water pressure (150 PSI)
- Maximum working water temperature (110°F)
- Hydrostatic test pressure (300 PSI)
- End connections threaded (ANSI 81.20.1)
1/2″, 3/4″, 1″, 1 1/4″, 1 1/2″, 2″