Conbraco 17-402-01 Relief Valve

The Conbraco 17-402-01 Relief Valve is a high-capacity hot water pressure relief valve engineered specifically for thermal expansion protection in ASME Section IV heating boilers and water storage systems. Built with a heavy-duty bronze body and corrosion-resistant stainless steel springs, this 3/4" MNPT x 3/4" FNPT valve is factory set at 75 PSI to ensure system integrity. With a thermal capacity of 505,000 BTU/hr, it provides an essential safety vent for high-output equipment, effectively preventing overpressure conditions in domestic and commercial hydronic heating systems. The silicone seat offers superior durability and high-temperature resistance up to 250°F, ensuring a tight seal after each lift. For contractors performing boiler maintenance or water heater repair, this Apollo relief valve meets ANSI Z21.22 and CSA requirements, making it a reliable choice for maintaining code compliance in pressurized water applications.

• ASME Section IV Certified: Designed and certified for high-capacity protection of hot water supply systems.
• Rugged Construction: Features a cast bronze body and stainless steel internal components for long-term service in harsh environments.
• High BTU Rating: Rated for 505,000 BTU/hr, suitable for large residential and commercial boilers.
• Superior Sealing: Equipped with a soft silicone seat to prevent weeping and ensure reliable reseating.
• Universal Compatibility: Standard 3/4 inch NPT connections facilitate fast installation on most standard water heaters and boilers.

What is the difference between a T&P valve and this pressure-only valve?
While a T&P valve reacts to both temperature and pressure, the Conbraco 17-402-01 is a pressure-only relief valve often used in systems where temperature is controlled by other safety limits, but thermal expansion protection is required.

Can this valve be installed horizontally?
For proper operation and to meet most local codes, safety relief valves should typically be installed in a vertical position with the discharge piping directed downward to a safe point of disposal.

When should this relief valve be replaced?
Technicians recommend inspecting the valve regularly for signs of mineral buildup or "weeping." If the valve fails to reseat after testing the lever or shows visible corrosion, it should be replaced immediately to ensure system safety.

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.