OPW 821 Anti Siphon Solenoid Valve 1 1/2 in. - 0 To 25 PSI

Mid-Flow Anti-Siphon Valve for Fuel Lines Serving High-Demand Generator Systems

The 1-1/2 in. OPW 821 is a normally closed, two-way diaphragm solenoid valve that prevents accidental siphoning from aboveground storage tanks when a downstream fuel line is compromised. The larger bore handles higher volumetric flow rates than the 1 in. version, making it the right fit for facilities with larger generator sets or longer fuel supply runs where line sizing needs to keep pace with engine demand. In data center environments, this translates directly to fuel delivery capacity: a generator starved of fuel during a grid event puts liquid cooling loops, CDUs, and active cold plate systems at risk when UPS reserves are exhausted. Properly sized fuel isolation at the tank is part of maintaining cooling continuity under load.

This valve opens on energization and returns to closed on signal loss or power failure, providing inherent fail-safe isolation without any additional controls. It's built for low-pressure petroleum service across a 0 to 25 PSI operating range, with no minimum pressure requirement. This makes it compatible with gravity-fed and low-head fuel systems.

Key specifications:

• Connection: 1-1/2 in. female NPT
• Operating pressure: 0 to 25 PSI
• Valve action: Normally closed, two-way diaphragm
• Body material: Aluminum
• Diaphragm, seals, and disc: Viton®
• Springs and core: Stainless steel
• Rider rings: Teflon®
• Disc holder: Nylon
• Core guide: Acetal/Delrin