Watts 0346040 Relief Valve

The Watts 0346040 (Series 174A) is a high-capacity ASME Section IV boiler pressure relief valve designed for commercial and industrial hot water heating applications. Featuring a 3/4 inch NPT inlet and outlet, this valve is factory-set to a 10 PSI relief pressure, providing critical overpressure protection for hot water boilers and storage tanks. The bronze body construction and non-metallic seat-to-disc design ensure long-term durability and prevent the valve from sticking during inactive periods. With a discharge capacity of 400,000 BTU/hr, the Series 174A is engineered for high-demand environments where maintaining system integrity is non-negotiable. Contractors rely on this 3/4 inch safety relief valve for its consistent performance and compliance with National Board requirements. Use this Watts 10# relief valve as a direct replacement component to ensure your hydronic system remains within safe operating limits while preventing catastrophic equipment failure.

• ASME Rated Capacity: Certified discharge rates ensure compliance with safety codes for large-scale heating systems.
• Corrosion Resistance: The rugged bronze body simplifies maintenance in harsh mechanical room environments.
• Reliable Reseating: The high-temperature silicone disc ensures a bubble-tight seal once pressure returns to normal.
• Large Orifice Design: Provides high-volume throughput to rapidly bleed off excess pressure.

Common Questions

What causes a relief valve to leak at 10 PSI? A weeping valve typically indicates a failing expansion tank or sediment buildup on the valve seat. For the Watts 0346040, ensure the system pressure is at least 25% below the 10 PSI set point to prevent simmer.

Can the Watts 174A be installed horizontally? No, pressure relief valves must be installed with the spindle in the vertical position to ensure proper mechanical operation and drainage.

Is the 10 PSI setting adjustable? This valve features a factory-preset and sealed adjustment to prevent unauthorized tampering; if your system requirements change, the entire unit must be replaced.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.