Watts 0382818 Valve

The Watts 0382818 (Model 740-1-45) is a heavy-duty, iron-body boiler pressure relief valve engineered specifically for high-capacity hot water space heating systems. Designed to protect vital equipment from over-pressurization, this valve features a 1-inch NPT inlet and an expanded 1-1/4 inch NPT outlet to facilitate superior discharge volume. Built for the rigors of the mechanical room, it utilizes a non-metallic disc-to-metal seat and a stainless steel spring to prevent sticking and freezing, even in systems with high sediment or aggressive water conditions. This ASME rated safety valve is factory-set at 45 PSI and delivers a massive 1,750,000 BTU/hr discharge capacity, ensuring rapid pressure stabilization during thermal expansion or control failure. The seat is positioned above the drain to prevent sediment buildup from fouling the seal, while a high-temperature water seal isolates internal working parts. This is a dedicated emergency safety relief component and must not be used as an operating control.

• High BTU Discharge Capacity: Rated for 1,750,000 BTU/hr, making it suitable for large-scale commercial and residential hydronic boilers.
• Corrosion-Resistant Iron Construction: Durable iron body with a stainless steel spring provides long-term reliability in demanding HVACR environments.
• Anti-Foul Seat Design: The seat is engineered above the drain line to ensure water and sediment cannot be trapped, preventing premature valve failure or leakage.
• Resists Sticking: Non-mechanical seat-to-disc alignment ensures the valve opens reliably at the 45 PSI set point without freezing.
• Expanded Outlet: The 1-1/4" expanded outlet allows for free-flowing discharge, reducing backpressure during critical relief events.

What is the maximum operating temperature for the Watts 0382818?
This valve is rated for a maximum temperature of 250°F (121°C), making it compatible with standard and high-temp hot water heating applications.

Is the 740-1-45 valve suitable for potable water systems?
No, this iron-body relief valve is specifically designed for non-potable hot water space heating boilers. It is not lead-free and should not be used in plumbing or domestic hot water systems.

Can I install this valve in any orientation?
To ensure proper drainage and prevent sediment accumulation, the valve should be installed with the spindle in the vertical position, following all local plumbing and mechanical codes.

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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.