Lennox 51M14 Flame Sensor

The Lennox 51M14 Flame Sensor is a critical safety component designed for precise rectification in Lennox G24, G24M, and G25 series furnaces as well as various Armstrong Air and Ducane HVAC units. This sensor, which is functionally identical to part number 51M1401, monitors the pilot or burner flame by converting heat into a microamp signal for the integrated furnace control board. When carbon buildup or oxidation occurs on the probe, the resistance increases, leading to furnace short cycling or ignition lockout. Engineered for high-temperature durability, this direct replacement flame sensor ensures the gas valve closes immediately if a flame is not detected, preventing hazardous gas accumulation. Technicians should verify microamp readings during routine preventative maintenance to ensure the flame rectification circuit is operating within manufacturer specifications. This component features a high-grade alumina ceramic insulator and a stainless steel sensor rod for long-term reliable performance in the combustion chamber.

• Compatible with Lennox part number 51M14 and 51M1401 for streamlined inventory management.
• Ensures accurate flame signal detection to prevent nuisance service calls and system lockouts.
• Constructed with high-heat resistant materials for longevity in gas-fired furnace environments.
• Features a standard mounting bracket for rapid installation and secure positioning within the burner assembly.
• Essential for maintaining the safety integrity of residential HVAC systems by preventing unburned gas flow.

How do I know if the flame sensor is failing? If the furnace ignites but shuts down after several seconds, the flame sensor is likely failing to send a sufficient microamp signal to the control board due to soot or oxidation.

Can I clean the 51M14 instead of replacing it? While cleaning with a non-abrasive material like steel wool can temporarily restore flame rectification, the protective coating is often compromised, making replacement the standard best practice for long-term reliability.

Is this compatible with generic flame sensors? While some universal probes exist, using the OEM Lennox 51M14 ensures the correct probe length and bracket alignment, which are vital for proper placement in the flame path.

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.