Watts 0358551 Relief Valve

For veteran contractors servicing high-capacity hot water space heating boilers, the Watts 0358551 (Model 374A-3/4-50) is a critical safety component designed for rigorous overpressure protection. This ASME-rated boiler pressure relief valve features a rugged iron body construction with a forged bronze inlet, ensuring durability in demanding commercial environments. Unlike standard residential valves, this unit delivers a high-discharge capacity of 950,000 BTU/hr at a factory-preset 50 PSI relief setting. The 3/4-inch NPT female connections facilitate direct integration into existing piping manifolds. Its non-mechanical seat-to-disc alignment is engineered to prevent sticking or freezing, while the above-the-drain seat design minimizes sediment accumulation that often fouls lesser valves. This direct-acting emergency safety relief valve is essential for maintaining system integrity and meeting strict mechanical codes in large-scale hydronic heating applications.

• High-Capacity Rating: Rated for systems up to 950,000 BTU/hr, providing necessary protection for large-scale commercial boiler equipment.
• Superior Metallurgy: Utilizes an iron body with a forged bronze inlet to resist corrosive water conditions and ensure structural longevity.
• Reliable Seating: Features non-metallic disc-to-metal seating and a stainless steel spring to prevent seat-sticking and ensure a clean pop-off during overpressure events.
• Standardized Fit: 3/4-inch NPT female inlet and outlet ports allow for a straight drop-in replacement for the original Watts 374A-3/4-50.
• Safety Compliance: Engineered as an ASME Section IV safety device for hot water heating boilers.

Is the 0358551 the same as the 374A-3/4-50?
Yes, the Watts 0358551 is the specific ordering code for the 374A-3/4-50 model; they are technically identical in construction and performance specifications.

What is the maximum BTU rating for this 50 PSI valve?
This specific relief valve is rated for 950,000 BTU/hr at the 50 PSI set point, making it suitable for high-output commercial boiler systems.

Can this be used as an operating control?
No, this is a safety relief valve designed for emergency pressure discharge only. It should never be used as a primary pressure regulator or operating control.

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.