Conbraco 17-402-03 Relief Valve

The Conbraco 17-402-03 is a high-capacity hot water pressure relief valve engineered for protection against over-pressurization in commercial and industrial boiler systems. Featuring a 3/4" Male NPT inlet and a 3/4" Female NPT outlet, this valve is factory-calibrated at a 125 PSI set pressure. With a discharge capacity of 791,000 BTU/hr, it meets the rigorous demands of large-scale hydronic heating systems. The bronze body construction and corrosion-resistant stainless steel spring ensure reliable seat reseating and long-term durability under high-temperature conditions. Designed as a safety relief valve for boilers, the 17-402-03 utilizes an EPDM O-ring for a positive seal and a silicone-sealed pop action to prevent simmering near set limits. This ASME Section IV pressure valve provides essential safety for hot water space heating boilers, ensuring system integrity by discharging excess pressure safely when thermal expansion or runaway heat occurs.

• High BTU Rating: Provides 791,000 BTU capacity, making it suitable for large-scale commercial boiler relief valve applications.
• Rugged Bronze Construction: Built with a heavy-duty bronze body and brass internals to withstand harsh mechanical environments.
• Precise 125 PSI Setting: Factory-tested to ensure accurate discharge and protecting the ASME pressure vessel from structural failure.
• Extended Service Life: Features a non-sticking Teflon-coated fabric-reinforced diaphragm and a stainless steel spring for consistent performance.

What is the maximum operating temperature for the Conbraco 17-402-03?
This valve is designed for hot water service and is typically rated for temperatures up to 250°F to ensure compatibility with high-output hydronic systems.

Can this relief valve be used for steam applications?
No, the 17-402 series is specifically engineered for hot water pressure relief. Steam applications require valves rated under ASME Section I or VIII with different lift characteristics.

Why is the 791,000 BTU rating significant for sizing?
When selecting a replacement relief valve, the valve’s BTU discharge capacity must exceed the gross BTU output of the boiler to prevent a catastrophic pressure buildup.

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.