OEM Lennox Dual Pressure Switch Assembly — 26W45

The genuine OEM Lennox 26W45 is a dual pressure switch assembly built for two-stage Lennox gas furnaces. This assembly combines two calibrated pressure switches so the control board can independently prove combustion airflow for both low-fire and high-fire operation. As the inducer draft changes between heating stages, the 26W45 confirms that safe venting is established at each firing rate before the corresponding stage is allowed to ignite.

When a dual switch like the 26W45 fails, you may see the furnace lock out on high fire while low fire works, an inducer that runs without ignition, staging faults, or intermittent no-heat calls. Cracked pressure tubing, a plugged condensate trap, or contacts stuck open on one of the two switches are the most common failure points.

Using the OEM Lennox 26W45 is essential because both switches are factory-matched to the exact set points your two-stage Lennox furnace requires. Substituting individual or generic switches risks incorrect staging, nuisance lockouts, and compromised safety logic. The factory assembly ensures correct fit, calibrated trip pressures for each stage, and reliable, code-compliant operation.