Backflow Reference Manual - Wilkins

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550 / 550A


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


This is a double check assembly. Production began approximately 1975 under the Richwell Model DC name. Around 1978 it was sold to the Neptune Meter Co. who produced it until 1984 as the 550. It was sold to the Wilkins Regulator Co. in 1984 and produced until 1995. The 3/4"-2" size are of bronze body construction. The check seats are cast into the body and are not replaceable. The original design of this unit had the check disc holders made of bronze. Approximately 1985 the disc holders were changed to glass filled noryl. In the 3/4"-1" size, there were several versions of the check covers produced. They could be either plastic or bronze. They could also be bolted on or screwed on. The 2 1/2"-6" body is cast iron with a fused epoxy coating to inhibit rust. Check seats are replaceable. In all sizes the checks are a piston type. Check springs are not contained when the cover is removed on the 3/4"-3" size. The 4"-6" size do have contained check springs when the cover is removed.


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.