Conbraco Industries 18C-402X-38 Valve

For high-demand commercial water heating systems, the Conbraco 18C-402X-38 Valve (also known under the Apollo brand) provides critical protection against thermal expansion and over-pressure conditions. This 3/4" MNPT x 3/4" FNPT T&P relief valve is engineered specifically with a 2" extended shank, allowing for proper installation on modern water heaters with thick insulation blankets without compromising the discharge path. With a factory-calibrated 150 PSI relief setting and a 210°F temperature limit, it delivers a certified 105,000 BTU/hr capacity for robust safety performance.

The unit features a 3" probe with a unique non-metallic, thermo-bonded coating that isolates the thermal element from the water, effectively preventing galvanic corrosion and mineral buildup that often lead to premature failure. Constructed with a cast bronze body and a rugged stainless steel spring, it is ASME Section IV certified and meets all ANSI Z21.22 and HUD/FHA requirements for pressure vessels. This is a reliable, veteran-choice component for ensuring system longevity and code compliance in professional HVACR and plumbing applications.

Key Benefits

• Extended Shank Design: The 2-inch body extension ensures the water heater relief valve clears heavy insulation, preventing restricted operation or improper discharge piping.
• Corrosion Resistant Element: The 3-inch probe features an advanced non-metallic coating that resists electromechanical corrosion and scale accumulation.
• High BTU Rating: Certified for 105,000 BTU/hr to handle high-performance commercial and residential tank applications.
• Durable Construction: Built with a cast bronze body and silicone seat to maintain a tight seal under constant thermal cycling and prevent leaking.
• Total Code Compliance: Meets ASME Section IV, CSA, and ANSI Z21.22 standards, making it suitable for any professional inspection or HUD/FHA project.

Common Questions

What is the purpose of the 2-inch extended shank on this valve?
On modern water heaters with extra-thick insulation, a standard relief valve might be buried within the jacket. The extended shank provides the necessary length to pass through the insulation, ensuring the T&P valve can be properly threaded and the discharge pipe remains accessible for maintenance.

Can the 18C-402X-38 be used for potable water systems?
Yes, this series is designed for hot water heaters and storage tanks. However, verify local lead-free requirements, as certain jurisdictions may require the lead-free (LF) version for specific potable water drinking applications.

How do I determine if 105,000 BTU is sufficient for my water heater?
The BTU rating of the temperature and pressure relief valve must always equal or exceed the BTU input rating of the heater itself to ensure the valve can safely vent the full output of the tank in an emergency.

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.