Backflow Reference Manual - Wilkins

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350 / 350A / 350XL / 450


3/4", 1", 1 /4", 1 1/2", 2", 2 1/2", 3", 4", 6", 8", 10", 12"


This is a double check assembly. Production of the 3/4"-2" began in 2004. The 3/4"-2" use a bronze carriage which holds a glass field noryl body containing the check mechanisms which nestles into the carriage. In 2010 a 350XL model was introduced that used lead free bronze. The checks are an in-line modular design. Spring tension is contained when the checks are removed from the body. The spring tension must be released to perform a repair of the checks. Production of the 2 1/2"-10" began in 1998. The 12" began in 2007. The 2 1/2"-12" body is made of epoxy coated ductile iron. In 2011 internal bronze trim items (e.g.bulkhead fittings, plates) were changed to lead free bronze. The check springs will be contained when the cover is removed. The checks are a glass filled noryl modular construction. The 2 1/2"-6" checks are held in the body by retainer clips while the 8"-12" checks are bolted into the body. The spring tension is contained when the checks are removed from the body. Spring tension does not have to be released to change the check discs. The model 350 is a straight horizontal piping orientation. The model 450 is able to be changed to provide an up and down or vertical piping orientation. Repair parts will be the same in both models. In 2004 the 350 became available in an "A" model (e.g.350A). The A model uses a grooved end valve body configuration as opposed to the flanged end valve body.


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.