The Lennox 18L11 (617168-01) is an OEM natural gas to LP/propane high altitude conversion kit designed for Lennox LF/LS25 series unit heaters. This kit allows safe and proper conversion from natural gas to propane by providing correctly sized orifices and required conversion components for operation at higher elevations. It is engineered to maintain proper combustion, efficiency, and reliability when propane fuel is required in elevated installations.

This conversion kit is specifically calibrated for applications up to 5,000 feet in the United States and up to 7,500 feet in Canada, making it suitable for a wide range of commercial and light industrial heating environments. As a genuine Lennox part, it ensures compatibility and performance when servicing or converting supported unit heaters.

 

Key features:

• OEM Lennox natural gas to LP/propane conversion kit
• Designed for high altitude operation
• Precision 0.0453" (1.15 mm) gas orifice sizing
• Supports safe, efficient propane combustion
• Engineered for direct compatibility with LF/LS25 unit heaters
• Ideal for service replacements or field conversions

 

Compatibility:

• Lennox LF/LS25 unit heaters
• Supported sizes: 30, 45, 60, 75, 90, 105

 

Specifications:

• Brand: Lennox
• Part Number: 18L11
• Lennox Reference Number: 617168-01
• Gas Type Conversion: Natural Gas to LP/Propane
• Orifice Size: 0.0453 inch (1.15 mm)
• Altitude Rating (US): 0–5,000 ft
• Altitude Rating (Canada): 0–7,500 ft
• Application: High altitude propane conversion