Lennox 18L12 Conversion Kit

The Lennox 18L12 (catalog number 617168-02) is a specialized Natural to LP/Propane Gas Conversion Kit engineered specifically for technical professionals working with Lennox LF25 and LS25 series unit heaters. This OEM-certified kit is the direct replacement for discontinued part numbers 165295205 and 20L07, ensuring seamless integration with existing manifolds and burner assemblies. It facilitates the safe transition of 125, 150, 175, and 200 capacity units from natural gas to liquid propane without compromising heat exchanger integrity or combustion efficiency.

Precision is maintained through eight #56 burner orifices (0.0571" / 1.45mm), optimized for specific manifold pressure requirements at standard altitudes. This kit is strictly compatible with units utilizing the White Rodgers 36G series gas valve and includes a dedicated 36G pressure measuring adapter for accurate field calibration. For high-altitude applications, technicians should note the rating of 0–5000 ft in the U.S. and 0–7500 ft in Canada to ensure stable pilot operation and flame characteristics.

Key Benefits

• Direct OEM Replacement: replaces legacy parts 165295205 and 20L07 with factory-correct specifications.
• Valve Compatibility: purpose-built for White Rodgers 36G valve systems, including the necessary pressure measuring adapter.
• Broad Capacity Coverage: supports large-scale heating units ranging from 125,000 to 200,000 BTUH.
• Technical Precision: contains #56 orifices for consistent fuel flow and reliable ignition.
• Regulatory Compliance: includes three critical conversion stickers to document system modifications for future inspections.

Common Questions

Which Lennox heater models can use the 18L12 kit?
This kit is designed for UHCM, LF25, UHSC, and LS25 series unit heaters with capacities of 125, 150, 175, and 200. Always verify your serial plate mentions these series and uses the 36G gas valve before installation.

Does this kit include the regulator spring?
Yes, the White Rodgers 36G Series Gas Valve Conversion Kit included in this package contains the heavier-duty spring required to convert the regulator to propane-level pressures.

What is the correct orifice size for this conversion?
The 18L12 kit utilizes 0.0571" (1.45mm) orifices, which are the industry standard for these specific Lennox heating capacities at standard altitudes.

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.