heat "short-circuits" up the chimney

provided the valve body is free of debris

or FC 302 units

or physical signs of backflow in the air intake

and mechanical assemblies

Lennox 63W26 Ignition Control R-407C heat "short-circuits" up the chimneyAs a direct replacement for your high efficiency gas furnace, the Lennox 63W26 Ignition Control (Honeywell S9220E1018 U) provides critical management for 2 stage ignition systems. This PSC integrated furnace control is engineered for residential natural gas or liquid propane applications, ensuring precise timing for the hot surface ignitor (HSI) and flame sensing sequences. High voltage 120V line power and 24V low voltage circuits are managed via a