Lennox 81W03 Control Board Els PW 17895 this indicates a restricted vent

this indicates a restricted vent pipe

114 DIA rod provides high sensitivity for accurate flame rectification measurements (microamps)

Designed to integrate seamlessly with PI (Intermittent Ignition) systems

Natural Gas Optimization: Specifically calibrated for natural gas flow rates to stabilize the pilot flame across varying pressure levels

Lennox 81W03 Control Board Els PW 17895 this indicates a restricted ventThe Lennox 81W03 Control Board is the direct OEM replacement for the Lennox 17W70, 17W7001, and 81W0301 ignition control boards. As the central logic for your furnace, this integrated furnace control manages critical sequences, including hot surface ignition, flame sensing, and blower motor timing. It is engineered specifically for use in high efficiency units such as the Lennox G40, G43, and ML180 ML193 series. When performing a field replacement,