Backflow Reference Manual - Watts

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800 M4 / LF800 M4 / 800 M4-FR


1/2", 3/4", 1", 1 1/4", 1 1/2", 2"


This is a pressure vacuum breaker. Production began in 1994. This is a bronze bodied unit. In 2010 a LF800M4 model was introduced which was constructed of lead free bronze. The check spring is contained when the bonnet is removed. The check seat is replaceable. A seat removal tool is needed to change the seat. The test cocks for this model are located on the ball valves and not on the assembly body. The 800M4 is a redesign of the 800M2 and 800M3 series with the only difference being the incorporation of a replaceable check seat. In 1995 the 800 M4 FR model was introduced. This model contains a small relief valve built into the air inlet float to prevent damage if the assembly froze.


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.