Lochinvar & A.O. Smith 100110739 Valve

The Lochinvar & A.O. Smith 100110739 is an OEM-spec 1-inch T&P relief valve engineered for high-output commercial and residential water heating systems. Designed to trigger at a 150 PSI pressure setting or a thermal limit of 210°F, this valve provides critical over-pressure and over-temperature protection to prevent catastrophic tank failure. It features a 1" MNPT inlet and 1" FNPT outlet, ensuring a high-capacity discharge flow rated at 500,000 BTU/hr (AGA) and 2,155,000 BTU/hr (ASME). This direct replacement for part number 9005924205 is essential for maintaining code compliance in closed plumbing systems where thermal expansion frequently challenges tank integrity.

For veteran contractors, the 100110739 valve is the standard for Lochinvar Knight and A.O. Smith Cyclone series units. Its 3-inch element probe ensures accurate core temperature sensing, while the heavy-duty construction handles the aggressive cycling common in industrial applications. When replacing a dripping T&P valve, verify the system's static pressure; if standard ratings are exceeded, this valve works in tandem with expansion tanks to stabilize the vessel. Prioritize this genuine OEM 100110739 to ensure precise seating and long-term reliability in demanding HVACR environments.

• Dual-Safety Protection: Automatically discharges when internal tank pressure hits 150 PSI or temperature reaches 210 degrees Fahrenheit.
• High Discharge Capacity: Rated for 500,000 BTU (AGA) to accommodate large-scale commercial water heaters and boilers.
• OEM Compatibility: Exact replacement for Lochinvar and A.O. Smith 100110739, ensuring a perfect fit without field modifications.
• Durable Construction: Built to withstand mineral buildup and sediment that typically cause leaking relief valves in hard water areas.
• Code Compliance: Meets ASME and AGA requirements for secondary safety controls on pressurized vessels.

What causes a T&P valve to leak or drip constantly?
Continuous dripping usually indicates the system pressure is approaching the 150 PSI limit due to thermal expansion or a failed pressure-reducing valve. It can also be caused by sediment preventing the internal disc from reseating properly.

Is the 100110739 compatible with other brands?
While primarily used for Lochinvar and A.O. Smith, it serves as a cross-reference for various commercial brands requiring a 1" NPT connection and 150# rating. Always check the BTU rating of your appliance to ensure it does not exceed the valve's discharge capacity.

When should this valve be replaced?
Technicians recommend replacement if there is visible corrosion, if the valve fails to open during a manual lever test, or if it has discharged significantly due to an over-temperature or over-pressure event.

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.