Backflow Reference Manual - Beeco/Hersey

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Hersey 6CM


2 1/2", 3", 4", 6", 8", 10"


This is a reduced pressure assembly. Production began approximately in 1977 and was discontinued in 2004. The bodies are constructed of both bronze and cast iron in the 2 1/2"-6" size. Be sure to specify which you have as the repair kits are different. The bronze body assemblies were discontinued in 2001. The 8"-10" body only come in cast iron. From 1977-1993 the cast iron bodies were galvanized coated. From 1991-1992 the HP painted epoxy was available as an option to the galvanized. In 1993 a fused epoxy coating became the standard. For temperatures from 140° -180° F there is a hot water repair kit available for the 2 1/2"-6". In 1988 the end to end body dimension on the cast iron bodies in sizes 2 1/2" and 4" were changed. The earlier model in the 2 1/2" cast iron body valve was 1 1/2" shorter than shown in the dimension chart. The 4" cast iron valve was 1" shorter. The repair parts are the same. The internal hardware parts are mostly bronze. The check and relief seats are replaceable on all sizes. A seat removal tool is needed to replace the check seats. The check and relief springs are contained on all sizes when the covers are removed. The RV spring tension has to be released to perform a proper repair. The relief valve sensing line is internal. From 1990-1992 the galvanized cast iron version adopted a plastic sleeve inside the RV sensing line, this was to eliminate rusting that occurred in the cast iron version which could plug up the sensing line. In 1993 the design of the check cover was changed. Before 1993 a gasket was used to seal the check covers to the body. After 1993 an O-ring seal was used on the check covers.


Common repair parts are a very small subset of the 10,000 plus items BAVCO stocks. Please feel free to contact us direct at 800-458-3492 for pricing on items not listed or backflow prevention devices.