Lochinvar & A.O. Smith 100165921 Flame Sensor

The Lochinvar & A.O. Smith 100165921 Flame Sensor is a critical OEM replacement part engineered for precise flame rectification in high-efficiency gas-fired systems. Designed as a direct crossover for the PLT30001 flame sensor, this component monitors the burner's ionization signal to ensure safe and continuous combustion. If your boiler or water heater is experiencing intermittent flame ignition failure or short-cycling, a fouled or oxidized flame rod is often the culprit. This sensor is manufactured with high-temperature resistant materials to withstand the intense thermal environment of the burner assembly, providing the control board with the reliable microamp signal required to maintain the gas valve circuit. Integration is seamless in compatible Lochinvar Knight and A.O. Smith gas boilers, where maintaining manufacturer standards is essential for both safety and equipment longevity. Clean the probe during annual maintenance to prevent carbon buildup and ensure optimal heating performance throughout the season.

• Direct OEM Compatibility: Serves as the exact functional equivalent to PLT30001, ensuring a perfect fit without field modifications.
• Enhanced System Safety: Provides rapid flame detection to prevent unburned gas accumulation in the combustion chamber.
• Contractor Grade Durability: Built with robust ceramic insulation and a high-grade metal alloy probe for extended service life in demanding HVACR applications.
• Optimized Signal Clarity: Delivers a consistent ionization current to the ignition module, reducing nuisance lockouts and flame failure errors.

How do I know if the 100165921 flame sensor is bad?
If the burner ignites but shuts off within seconds, the sensor may not be sending a sufficient microamp signal. Technicians should test the signal with a multimeter; if the reading is below the manufacturer's specified threshold (typically 1.0 to 5.0 µA), check for carbon buildup or replace the sensor.

Is the 100165921 interchangeable with the PLT30001?
Yes, the 100165921 is the updated manufacturer part number and is a 100% direct replacement for the PLT30001. No additional brackets or wiring adjustments are necessary for installation.

Can I clean this flame sensor instead of replacing it?
While light oxidation can sometimes be removed with a fine abrasive pad like Scotch-Brite, deep pitting or cracked ceramic insulation necessitates a full replacement to ensure reliable operation and prevent future emergency service calls.

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.