Conbraco 10-303-05 Relief Valve

The Conbraco 10-303-05 Relief Valve is a high-capacity, ASME Section IV certified safety component engineered specifically for hot water heating boilers and hydronic systems. Featuring a rugged bronze body (ASTM B584) and a corrosion-resistant stainless steel spring, this 3/4" FNPT x 3/4" FNPT valve is factory-set at 30 PSI to prevent over-pressurization in demanding residential and commercial applications. With a discharge capacity of 550,000 BTU/hr and a maximum temperature rating of 250°F, it provides reliable protection against thermal expansion and over-firing conditions. The internal EPDM seat ensures a tight seal and positive shut-off after lift-off, while the top-guided design and diaphragm isolated spring chamber protect critical working parts from scale and water-borne contaminants. This industry-standard Apollo RVW30F series valve is the preferred choice for contractors requiring a high-flow, National Board certified relief solution that meets strict boiler code requirements.

• ASME Section IV Certified: National Board rated for emergency steam discharge in hot water systems.
• High BTU Capacity: Manages up to 550,000 BTU/hr, suitable for significant heating loads.
• Corrosion Resistance: Built with a heavy-duty bronze body and stainless steel internal components.
• Standard Fitting: 3/4" Female NPT inlet and outlet allow for straightforward drop-in replacement.
• Temperature Resilience: Engineered to perform in high-heat environments up to 250°F.

What is the difference between this and a standard T&P valve?
Unlike a Temperature and Pressure (T&P) valve used on water heaters, this hot water relief valve is specifically designed for ASME Section IV boilers. It monitors pressure thresholds rather than temperature probe activation, making it essential for hydronic heating loops.

Can I install this valve horizontally?
No. To ensure proper pop-type action and drainage, this valve must be installed in a vertical position with the discharge piping sloped for gravity drainage as per local mechanical codes.

Is this relief valve compatible with glycol systems?
Yes, the EPDM seat and bronze construction are compatible with typical propylene and ethylene glycol mixtures found in closed-loop hydronic systems.

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.