Lennox Furnace Error Code E228

E228 means the furnace control board was unable to complete its automated pressure switch calibration sequence. The pressure switch is a safety component that verifies the inducer motor is producing enough draft before ignition is allowed. When calibration fails, the furnace shuts down to avoid unsafe operation. Common causes include vent blockages, a faulty pressure switch, or loose wiring connections.

The furnace is designed to wait 300 seconds and then retry the calibration sequence automatically. A manual reset may allow one additional attempt, but if the underlying problem is not resolved, E228 will return. Clearing the code without correcting the root cause, such as a blocked vent or bad pressure switch, will not restore reliable furnace operation.

If the fix is simply clearing a blocked vent or reseating a loose wire, costs are minimal and may involve only a service call fee, typically in the range of $75 to $150. Replacing a failed pressure switch generally costs between $100 and $250 including parts and labor. An inducer motor replacement is more involved and can range from $300 to $700 or more depending on the specific model and local labor rates.

Some causes of E228, such as a blocked exterior vent termination or a disconnected pressure hose, can be identified and corrected without special tools. However, testing pressure switch continuity and evaluating inducer motor performance typically requires a multimeter and familiarity with furnace components. If the error returns after checking vents and wiring, a qualified HVAC technician should perform further diagnostics.

When E228 is active, the furnace has already shut itself down and will not attempt ignition until the calibration issue is resolved. The error is a protective lockout, so the system is not operating in an unsafe state while displaying the code. However, you should diagnose and repair the cause promptly to restore heat and ensure the pressure and venting systems are functioning correctly.