Lennox 18L39 (105982-11) is a high-altitude pressure switch kit designed to maintain safe and reliable furnace operation where air density is reduced. Engineered to actuate at 0.55" W.C., this White Dot switch ensures proper draft induction and combustion safety for Lennox high-efficiency heating systems. It provides precise airflow monitoring, helping protect the heat exchanger and maintaining compliant performance across elevated elevations. The kit is built to OEM Lennox specifications for accurate replacement, consistent pressure control, and long-term dependability.

Applications include high-altitude installations where standard pressure switches may not operate correctly due to thinner air conditions. This OEM component helps restore furnace operation, prevent pressure-related lockouts, and preserve overall system efficiency.

 

Key features :

 

• Designed for high-altitude furnace operation where air density is reduced
• Actuates at 0.55" W.C. for precise and reliable pressure control
• OEM Lennox White Dot specification for accurate airflow monitoring
• Helps prevent pressure-related furnace lockouts and safety faults
• Ensures proper draft induction and combustion performance
• Direct replacement for compatible Lennox high-efficiency gas furnaces