OEM Lennox Draft Inducer Gasket — 21W66

The genuine OEM Lennox 21W66 draft inducer gasket forms the airtight seal between the draft inducer assembly and the furnace collector box or heat exchanger, ensuring combustion byproducts are drawn and vented exactly as engineered. This gasket maintains the precise pressure differential the inducer relies on to satisfy the pressure switch and move flue gases safely out of your Lennox furnace.

A worn, cracked, or hardened gasket allows air and flue-gas leaks that disrupt inducer pressure, causing pressure switch faults, ignition lockouts, whistling or hissing noises around the inducer, or a furnace that short-cycles. Because a compromised seal can also permit combustion gases to escape, replacing a deteriorated gasket is both a performance and a safety concern.

An OEM Lennox 21W66 gasket is die-cut to the exact dimensions, bolt pattern, and high-temperature material specification of your inducer housing. Generic or trimmed-to-fit gaskets rarely seal correctly against warm, vibrating surfaces and can fail prematurely. Fit the factory replacement to restore a proper seal and correct inducer pressure. Always replace the gasket whenever the draft inducer is removed or serviced.