Lennox EL296UHV Error Code E 228: Combustion Air Inducer Calibration Failure
What Does Code E 228 Mean?
Error code E228 on the Lennox EL296UHV indicates a combustion air inducer calibration failure. Before each ignition sequence, the control board runs a calibration routine that measures the baseline pressure readings from the pressure switches to ensure they are functioning correctly. If this calibration cannot be completed, the board flags E228.
The calibration process checks that the pressure switches respond properly to changes in inducer speed. If the switches do not respond as expected — due to loose hose connections, cracked tubing, a blockage in the vent system, or a pressure switch that is not seating properly — the calibration fails and the furnace will not attempt ignition.
The error clears once the calibration succeeds on a subsequent attempt. A technician should inspect the pressure switch wiring and hose connections, check the vent system for restrictions, and verify the inducer motor is operating at the correct speeds. If the vent system and wiring are in good condition, the pressure switches themselves may need replacement.
When to Call a Professional
Contact a licensed HVAC technician if:
- The furnace is not attempting to ignite due to calibration failure
- The pressure switch hoses and wiring need professional inspection
- E228 returns after power cycling the furnace
✓ Verified against manufacturer service manual — March 2026