Lennox 52M72 Flame Sensor

The Lennox 52M72 Flame Sensor is a critical safety component designed for precise flame rectification in high-efficiency gas furnaces. Engineered for direct spark ignition (DSI) and hot surface ignition (HSI) systems, this OEM replacement probe detects the presence of a burner flame by translating it into a microamp signal for the integrated furnace control. Built with high-grade alumina ceramic insulation and a durable stainless steel electrode, it effectively prevents nuisance lockouts caused by carbon buildup or high-ohm resistance. This technician-grade component is the direct replacement for Lennox 52M7201 and is widely compatible with G24, G32, and elite series air handlers. When troubleshooting short cycling furnace issues or intermittent ignition failures, verifying the microamp reading on this sensor is a standard diagnostic step. Proper installation ensures consistent HVAC furnace maintenance and reliable heating cycles throughout the season.

Key Performance Benefits

• Optimized Conductivity: High-purity stainless steel probe ensures accurate flame rectification signal transmission to the control board.
• Broad Compatibility: Primarily used in Lennox, Armstrong, and Ducane units, replacing obsolete or failing 52M7201 sensors.
• Heat Resistance: The robust ceramic insulator prevents electrical leakage even during prolonged exposure to high-temperature combustion.
• Direct Replacement Fit: Standard mounting bracket allows for rapid field installation without modification to the burner assembly.

Common Technical Questions

How do I know if the Lennox 52M72 is failing?
If the furnace burner ignites for several seconds and then shuts down, the system is likely not receiving a sufficient microamp signal. Technicians should check for a cracked insulator or heavy oxidation on the probe surface.

Can I clean the 52M72 flame sensor instead of replacing it?
While cleaning with a non-conductive abrasive pad can provide a temporary fix for carbon soot, replacement is recommended for long-term reliability if the metal is pitted or the ceramic is compromised.

What is the typical microamp range for this sensor?
Depending on the specific Lennox control board, a healthy Lennox 52M72 Flame Sensor should typically produce a signal between 2.0 to 6.0 microamps during normal operation.

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.