Milwaukee Valve 509Y 3" Swing Y Check Valve 7.875 in

3-inch Y Swing Check Valve

This bronze check valve uses a Y-pattern swing mechanism to prevent reverse flow in plumbing and industrial piping. It accepts 3-inch FNPT threaded connections on both ends and handles water pressure up to 200 psi at 150 degrees Fahrenheit. The unit is rated for steam service up to 125 psi WSP and operates across a temperature range of -20 to 425 degrees Fahrenheit.

Cracking pressure and orientation limits

The valve opens with a low cracking pressure of 0.5 psi, which suits gravity-fed or low-head systems but may allow unwanted seepage in high-backpressure installations. It is approved for both horizontal and vertical mounting orientations, though vertical use requires upward flow to ensure the disc seats properly by gravity. Maximum flow capacity reaches 297 gallons per minute with full port opening.

Bronze body and threaded connections

The body, seat, and seal are all bronze, providing consistent corrosion resistance without dissimilar-metal galvanic concerns at the sealing faces. FNPT threads demand accurate pipe threading and appropriate sealant to achieve the rated 200 psi water seal. The 7.875-inch overall length determines the face-to-face spacing required in the pipeline layout.