Lochinvar & A.O. Smith 100109721 Upper Probe

The Lochinvar & A.O. Smith 100109721 Upper Probe is a critical OEM replacement part engineered for the inner control assembly of high-efficiency commercial water heaters. As a high-performance hot surface igniter, this 100109721 probe is essential for ensuring reliable ignition cycles and precise flame sensing in BTH Series units. Designed to meet exact factory specifications, it eliminates the common failure points associated with generic aftermarket components, providing the heat resistance and electrical conductivity required for natural gas and propane applications. This upper probe assembly is cross-referenced with part number 9004238215 and is built to withstand the rigorous cycling of commercial environments. For technicians servicing Cyclone water heaters, integrating this genuine component ensures the combustion system maintains its peak efficiency and diagnostic accuracy, preventing nuisance lockouts and ensuring consistent burner performance across the 120 through 250 series models.

• Precise Ignition Timing: Engineered specifically for high-efficiency water heaters to ensure consistent lighting and burner stability.
• OEM Compatibility: Exact replacement for A.O. Smith, Lochinvar, State, and American commercial gas units, specifically the BTH, SUF, and HCG series.
• Industrial-Grade Build: Constructed with materials designed to handle the high-thermal loads of commercial heating cycles without premature ignition failure.
• Direct Fitment: Replaces 100109721 and 9004238215, featuring a plug-and-play design for the inner control assembly.

• Which models is this probe compatible with? This probe is specifically designed for commercial gas water heaters including the BTH 120-250 series and comparable Shield and Cyclone units.
• Can this be used for both Natural Gas and Propane units? Yes, the 100109721 igniter is rated for use with both fuel types in supported commercial assemblies.
• Does this include the lower probe? No, this is the Upper Probe for the inner control assembly only; verify your diagnostic codes to ensure this is the specific sensor required.

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.