Lochinvar & A.O. Smith 100108348 Gas Valve

The Lochinvar & A.O. Smith 100108348 Residential Natural Gas Valve is the direct service replacement for legacy 37C73U-640 and 9000246005 control units. Engineered for tight manifold pressure regulation, this White-Rodgers gas valve features an integrated Energy Cut Off (E.C.O.) high-limit switch to prevent over-temperature conditions in residential water heaters and boilers. As a veteran-grade HVAC replacement part, it utilizes a 1/2-inch NPT inlet and 1/2-inch inverted flare outlet, typically calibrated for a standard 3.5" W.C. natural gas output. The internal diaphragm is designed for precision gas flow modulation, ensuring proper stoichiometric combustion and reducing hazardous discharge during the ignition cycle. Whether you are troubleshooting a pilot failure or a faulty solenoid winding, this genuine OEM gas control valve provides the reliability required for high-demand hydronic and potable water heating systems. Its robust brass construction and built-in pilot gas filter provide superior debris protection, maintaining long-term seat integrity and preventing common gas valve sticking issues frequently encountered in older A.O. Smith and Lochinvar units.

• Universal Compatibility: Serves as the updated OEM replacement for 100108348, effectively superseding multiple White-Rodgers 37C73U series models.
• Enhanced Safety: Includes a non-cycling Energy Cut Off (E.C.O.) and automatic shut-off feature for both main and pilot gas in the event of flame failure.
• Technical Precision: Factory-set for natural gas applications with an adjustable temperature range of 70°F to 160°F for versatile residential installs.
• Installation Efficiency: Features a standard 1/2" NPT connection and a manifold pressure tap for quick manometer calibration and combustion analysis.

• How do I verify if the 100108348 is faulty? Use a multimeter to check for 24V at the solenoid terminals during the call for heat. If voltage is present but the valve fails to click or output gas, the internal windings or seat may be compromised.
• Can this valve be converted to Liquid Propane (LP)? While some White-Rodgers bodies allow for spring kits, this specific model is configured for Natural Gas. Always refer to the manufacturer’s data plate before attempting any gas type conversion.
• What is the primary cause of E.C.O. lockout? Overheating due to scale buildup or a failed thermostat sensor can trigger the non-cycling high limit, requiring a full valve replacement to restore safe operation.

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.