Lochinvar & A.O. Smith 100073343 Flame Sensor

The Lochinvar and A.O. Smith 100073343 flame sensor is a critical safety component designed for precise flame rectification in high-efficiency water heaters and boilers. Engineered to withstand high-ambient combustion chamber temperatures, this direct spark ignition flame probe ensures the integrated control board receives a consistent microamp signal, preventing nuisance soft lockouts or ignition failures. This genuine OEM replacement part (formerly 100073343 and 9006240005) includes the necessary high-temperature gasket to ensure a gas-tight seal at the mounting flange. It is compatible with a wide range of commercial water heaters, including the Lochinvar Knight and A.O. Smith Cyclone series. When diagnosing hot surface ignition or spark-to-burn issues, verifying the integrity of this sensor is essential for maintaining system uptime and combustion efficiency. The durable ceramic insulator and high-grade stainless steel rod provide reliable conductivity across thousands of heating cycles.

Key Benefits for the Contractor:

• Optimized Signal Strength: Delivers accurate microamp feedback to the ignition module to prevent intermittent flame failure codes.
• Direct OEM Compatibility: Replaces Lochinvar 100073343 and A.O. Smith 9006240005 across Cyclone, Knight, and Armor product lines.
• Installation Ready: Includes the mounting gasket required to maintain proper combustion chamber pressure and safety standards.
• Robust Materials: Features high-grade alloys to resist carbon buildup and oxidation in condensing boiler environments.

Common Questions:

How do I test the 100073343 flame sensor?
Set your multimeter to the microamp (µA) scale and connect it in series with the sensor wire. You should typically see a stable reading between 2.0 to 5.0 microamps during the burner cycle, depending on the specific control board requirements.

What are the symptoms of a failing flame sensor?
The most common symptoms include the burner lighting for a few seconds and then shutting down, or the system throwing an ignition failure code despite a visible flame being present.

Can I clean the 100073343 sensor rod?
While light cleaning with a non-abrasive pad can temporarily restore flame sensing, pervasive oxidation or cracks in the ceramic insulator require a full replacement to ensure long-term reliability.

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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.