4"

The 4" Hersey model 2 is a Double Check Valve that was produced from 1975 to 2004. It has a cast iron body. From 1977-1993 the cast iron bodies were galvanized coated. From 1992-1993 the HP painted epoxy was available as an option to the galvanizing. In 1993 a fused epoxy coating became the standard. In 1988 the device lay length changed. The earlier model being 1" shorter. Despite the change, repair kits remain the same. Check seats are removable but a seat removal tool is needed. in 1993, the check cover design was changed. Early models used a cover gasket and after the change, a cover O-Ring was used. Hard parts are no longer available and only rubber repair parts are available.