Lochinvar & A.O. Smith 100279407 Flame Sensor

The Lochinvar & A.O. Smith 100279407 Flame Sensor is a critical safety component engineered for precise flame rectification in high-efficiency boilers and water heaters. This original equipment manufacturer (OEM) part is designed for rear-mount installation, ensuring the control module receives an accurate microamp signal once a flame is established. When your system faces intermittent ignition lockouts or fails to sense a burner flame, replacing the probe with a genuine 100279407 prevents unnecessary gas valve cycling and system shutdowns. This kit includes the flame sensor probe, a high-temperature mounting gasket, and the necessary replacement hardware to ensure an airtight seal against the combustion chamber. Built to withstand extreme thermal stress, it maintains continuity and prevents carbon buildup from causing false readings. Compatibility includes several Lochinvar Knight and A.O. Smith Cyclone series models where reliable flame ionization is required for a safe ignition sequence.

Technical Benefits for Contractors

• Direct OEM Replacement: Matches exact factory specifications for the 100279407, eliminating the voltage drop issues often found in universal aftermarket rods.
• Complete Service Kit: Includes the flame sensor gasket and mechanical fasteners, ensuring a proper seal and preventing flue gas leakage during maintenance.
• Enhanced Signal Stability: Optimized for accurate microampere (µA) signal transmission to the integrated control board.
• High-Temperature Durability: The rod alloy is engineered to resist oxidation and warping in high-BTU combustion environments.

Common Questions

How do I know if the Lochinvar 100279407 needs replacement?
If your boiler cycles briefly and then locks out with a "No Flame Detected" error, first check for 1-5 microamps at the control board. If the rod is cleaned but the signal remains low or inconsistent, the 100279407 flame sensor should be replaced.

Does this fit both Lochinvar and A.O. Smith units?
Yes, this is a shared common part number (100279407, formerly 9004443005) used across several commercial and residential product lines, including many Knight (KBN/KBN) and Cyclone (BTH) models.

Is the gasket required for installation?
Yes. Always replace the mounting gasket when pulling the sensor to ensure the combustion chamber maintains its pressure integrity and to prevent CO leaks.

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.