OEM Lennox Electronic Igniter — 45M47

The genuine OEM Lennox 45M47 electronic hot surface igniter, also referenced as part 51805U, is responsible for lighting the burners in your Lennox gas furnace. When the thermostat calls for heat, the control board energizes this igniter, which heats to a high temperature and ignites the gas as it enters the burner assembly. Manufactured to Lennox factory specifications, it delivers reliable, consistent ignition cycle after cycle.

A failing igniter is one of the most common causes of no-heat calls. Symptoms include the furnace blower running with no warm air, the igniter glowing weakly or not at all, repeated ignition lockouts, or a cracked and visibly damaged element. Igniters are brittle and degrade with each heating cycle, so replacement is a routine part of furnace maintenance.

Choosing an OEM Lennox 45M47 igniter matters because the element resistance, mounting bracket, and connector must match your furnace precisely. Generic igniters can draw incorrect current, seat improperly, or fail prematurely. This factory part ensures fast, dependable ignition and safe operation of your Lennox equipment.