McDonnell & Miller 250-1-50 Valve

The McDonnell & Miller 250-1-50 is a high-capacity 1" NPT pressure relief valve engineered specifically for technical requirements in hydronic heating systems and large storage tanks. Designed to meet ASME Section IV safety standards, this valve features a robust bronze body and seat, providing the durability required for commercial and industrial boiler applications. With a fixed factory setting of 50 PSI and a significant 1,710,000 BTU capacity, it ensures critical over-pressure protection by utilizing an EPDM rubber diaphragm and seat disc. The "oversized" effective diaphragm area generates higher operating force, which effectively overcomes potential fouling issues common in older systems. This McDonnell & Miller 182225 valve maintains a low differential pressure—approximately 3 PSI between opening and closing—to minimize the risk of flash steam hammering. For contractors performing boiler pressure relief valve replacement, this unit offers a reliable, fail-safe disc design that maintains safety functions even in the rare event of diaphragm rupture.

Key Benefits

• ASME Section IV Certified: Specifically labeled and tested to meet rigorous safety codes for hot water pressure vessels.
• High BTU Rating: Manages up to 1,710,000 BTU/hr, making it suitable for large-scale commercial hydronic boilers.
• Fouling Resistance: High-area diaphragm design ensures consistent operation even when faced with system sediment or buildup.
• System Stability: Engineered to reduce hammering effects with flash steam through precise pressure differential management.
• Heavy-Duty Construction: Features a corrosion-resistant bronze body with an EPDM rubber seat disc for long-term sealing integrity in 250°F environments.

Common Questions

What is the maximum operating temperature for the McDonnell & Miller 250-1-50?
This valve is rated for a maximum operating temperature of 250°F (121°C), ensuring performance in high-demand heating loops.

Can this valve be used for steam applications?
The Series 250 is primarily designed for hot water heating systems and storage tanks. Always verify your specific boiler’s nameplate requirements against the 1,710,000 BTU capacity before installation.

Is the 50 PSI relief setting adjustable in the field?
No, these valves are factory-set and sealed at 50 PSI to comply with ASME safety standards and ensure consistent system protection.

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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.