Hersey Model FDC Large DIameter Backflow Assembly was discontinued in 2004, the Hersey Model No. 2 from 1975 and discontinued in 2004 and the Hersey DDC II Model was produced from 1975 and was discontinued in 2004. The model FDC 3/4" is used on the bypass. In 1988 the end to end dimension of the main body on the 3" and 4" sizes were changed. The earlier model of the 3" was 5/8" shorter. The earlier model of the 4" was 1" shorter.

This model is currently obsolete!