Lochinvar & A.O. Smith 100110089 Gas Valve

The Lochinvar & A.O. Smith 100110089 is a technical-grade 3/4" MV Natural Gas Valve designed for reliability in standing pilot systems. This millivolt gas valve operates on a 750mV signal, making it a critical component for high-output heating applications like the BT-365 series. As a veteran-verified direct replacement for 36C04U-438, it features a step-open (slow opening) characteristic to ensure soft ignition and stable combustion efficiency during startup. The main regulator is factory-calibrated for a 3.5" W.C. outlet pressure but maintains an adjustable range of 2.5" to 5.0" W.C. to accommodate specific field requirements. Built with a straight-through flow pattern and a 1/4" compression pilot gas connection, this OEM gas control simplifies retrofitting obsolete White-Rodgers 36C series units. Its robust design handles a maximum inlet pressure of 0.5 PSI, providing the 100% shut-off safety required for commercial water heaters and boilers.

• Precision Startup: The step-opening gas valve design reduces ignition noise and prevents "booming" during the light-off cycle.
• Millivolt Compatibility: Engineered for 750mV systems, eliminating the need for external power in standing pilot configurations.
• Universal Replacement: Serves as the official Lochinvar 100110089 and A.O. Smith 100110089 substitute for the discontinued 36C04U-438.
• High Capacity: Optimized for large-scale equipment with its 3/4" x 3/4" NPT pipe sizing and high BTU throughput.

• What does "Step-Open" mean for my installation? This feature allows a controlled initial gas flow (typically around 0.7" W.C.) before ramping up to the full manifold pressure, ensuring a smoother and safer ignition.
• Can I use this for Propane (LP) conversions? While this specific model is factory-set for Natural Gas, it is part of the 36C series; always verify the specific orifice and internal spring requirements before attempting any fuel conversion.
• Why am I getting 750mV but the valve won't open? Ensure the thermopile output stays consistent under load; if the voltage drops significantly when the thermostat calls for heat, the issue is likely the generator, not the coil.

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.