Watts 0382008 Valve

The Watts 0382008 (Series 740-3/4-30) is a high-capacity boiler pressure relief valve engineered specifically for hot water space heating applications. Featuring a rugged iron body and a 3/4-inch FNPT inlet with an expanded 1-inch FNPT outlet, this ASME Section IV certified valve is designed to manage thermal expansion and prevent over-pressurization in commercial and residential systems. With a factory set point of 30 PSI and a discharge capacity of 925,000 BTU/hr, it provides critical safety redundancy. The Watts 740 series utilizes a non-mechanical seat-to-disc alignment that prevents sticking or freezing even in corrosive water conditions. The raised seat design ensures that sediment cannot foul the seal, while the high-temperature resistant water seal isolates the stainless steel spring from the flow path. This part is a direct replacement for 382008 and 740-030-FS, ensuring seamless HVAC system compatibility during boiler maintenance or emergency repairs.

• Inlet Connection: 3/4" NPT Female
• Outlet Connection: 1" NPT Female (Expanded)
• Pressure Setting: 30 PSI
• Steam Capacity: 925,000 BTU/hr
• Max Temperature: 250°F (121°C)
• Body Material: Cast Iron with Stainless Steel Spring

• Anti-Foul Seat Design: The raised seat prevents mineral buildup and sediment trapping, ensuring the Watts 0382008 pressure valve maintains a tight seal over long-term operation.
• High-Flow Expanded Outlet: An oversized 1-inch discharge port allows for rapid pressure reduction during emergency blow-off events, meeting ASME safety standards.
• Fail-Safe Alignment: The non-mechanical disc alignment eliminates the risk of the internal components sticking due to thermal cycling or oxidation.
• High-Temperature Durability: Rated for systems up to 250°F, providing reliable performance in high-demand hydronic heating systems.

Is the Watts 0382008 compatible with low-pressure steam boilers?
No, the Watts 0382008 is specifically rated for hot water space heating boilers. For steam applications, you must use a valve rated for ASME Section I or Section VIII steam service.

Why is my relief valve dripping through the discharge line?
Dripping is usually caused by thermal expansion in a closed system or sediment preventing the disc from reseating correctly. Ensure your expansion tank is pressurized and the system pressure is below 30 PSI.

Can I install this valve with the discharge pointing upward?
No. The discharge line must be piped the same size as the valve outlet and must pitch downward to a safe, visible floor drain to prevent water trapping and corrosion.

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.