OEM Lennox Elite Single-Stage Ignition Control — 74W03

The Lennox 74W03 (factory part number 103098-01) is a genuine OEM single-stage ignition control designed for Lennox Elite series furnaces. This integrated control manages the ignition sequence for single-stage heating — coordinating the inducer motor, hot surface or spark igniter, gas valve, flame sensing, and blower timing to deliver safe, reliable warmth on every call for heat.

Common failure symptoms include no ignition, repeated ignition lockout, short cycling, a furnace that will not respond to the thermostat, error or fault codes on the control's diagnostic LED, or the blower and inducer running erratically. Because this board handles flame verification, a failing 74W03 will often shut the system down as a safety precaution, leaving you without heat.

Why OEM matters: The 74W03 is built to the precise timing, flame-sense sensitivity, and voltage tolerances your Lennox Elite furnace requires. Aftermarket substitutes may not match the factory ignition profile, leading to nuisance lockouts, unsafe flame conditions, or premature failure. Choosing the OEM control ensures correct sequencing, protects your warranty, and keeps your Lennox Elite system operating exactly as engineered.