Lennox 73W81 (604913-03) is an OEM LP/Propane to Natural Gas Conversion Kit engineered for safe, precise fuel changeover on compatible Lennox furnace models. Designed to maintain proper combustion, heating performance, and manufacturer integrity, this kit provides the calibrated components required for a clean and reliable transition back to natural gas operation.

• Genuine Lennox conversion kit for changing fuel source from LP/propane to natural gas
• Compatible with ML180, EL180, ML193, ML195, EL195, 80AF1, 92AF1, and 95AF1 series furnaces
• Includes natural gas burner orifices, regulator spring, conversion labels, and hardware
• Supports correct manifold pressure and proper combustion setup when adjusted by a licensed technician
• Helps maintain reliable ignition, stable flame characteristics, and rated heating output after conversion
• Professional installation required; follow Lennox service instructions and local code compliance

Additional details:

• Orifice size: 0.063 inch
• Designed for standard elevation installations; high-altitude systems may require a different pressure switch (sold separately)
• Conversion must be documented using included labeling to maintain service and safety compliance
• Intended for furnaces originally equipped for propane operation; confirm model and serial before ordering