Lennox 27F74 Flame Rod Lead

The Lennox 27F74 Flame Rod Lead is a critical replacement component for maintaining reliable flame rectification in Lennox furnace ignition systems. This high-temperature insulated wire, finished in white, provides the electrical path between the ignitor-flame sensor assembly and the integrated furnace control board. Designed for precision, the 27F74 is technically identical to the Lennox 27F7401, ensuring 100% compatibility across residential and commercial HVAC units that utilize these specific catalog numbers. When dealing with "no flame" calls or intermittent flame sense microamp signals, replacing a brittle or corroded lead wire is often the final step to ensure the SureLight control receives the necessary 0.2 to 2.5 microamps for continuous burner operation. This HVAC replacement part is built to withstand the high-ambient temperatures of the burner vestibule, preventing signal leakage that leads to nuisance lockouts and diagnostic error codes like "E250" or "Low Flame Signal."

• Direct OEM Matching: Drop-in replacement for Lennox 27F7401 and 27F74, eliminating the need for field modifications.
• Enhanced Signal Integrity: Designed to carry low-voltage flame rectification signals without impedance, ensuring stable burner cycles.
• Thermal Resistance: Specifically engineered insulation prevents melting or grounding out when routed past hot furnace components.
• Simplified Maintenance: Features standard spade connectors for rapid attachment to the flame sensing rod and control module.

Is the 27F74 compatible with the 27F7401?
Yes, these parts are functionally and physically identical. The 27F74 part number is frequently used interchangeably with the 27F7401 in Lennox technical manuals and parts catalogs.

Why is my furnace giving a 'Low Flame Signal' code if the rod is clean?
If the flame rod is free of carbon deposits, the issue often lies in the flame rod lead. A degraded wire can cause resistance or intermittent grounding, preventing the control board from seeing the proper microamp signal.

Can I use this on Armstrong or Ducane furnaces?
While many Lennox-brand components cross over to Allied Air brands (Armstrong/Ducane), you should verify the specific part number in your unit's service manual to ensure the lead length and terminal connections match.

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.