Lennox Furnace Error Code E222

E222 means the low pressure switch has failed in the closed position. This switch is part of the combustion air safety circuit and should only close when the inducer motor has established proper negative pressure. When the control board detects the switch is closed at the wrong time, it locks out the furnace and displays E222 to prevent unsafe ignition.

No. The E222 lockout exists because the low pressure switch is part of the combustion air safety circuit. Running the furnace without a properly functioning pressure switch means the system cannot verify that adequate draft and airflow are present before ignition. Operating under these conditions could result in incomplete combustion or carbon monoxide buildup. The furnace should remain off until the fault is properly diagnosed and repaired.

Resetting the furnace may temporarily clear the E222 code and allow the furnace to attempt operation again, but if the underlying problem is not corrected, the code will return. A pressure switch that is mechanically stuck closed, a blocked flue, or a failing inducer motor will continue to trigger the fault on every startup cycle. A reset should only be used as part of a diagnostic process, not as a long-term solution.

Some causes of E222, such as a blocked vent pipe, a kinked pressure switch hose, or condensate in the hose, can be inspected and corrected by a knowledgeable homeowner. However, testing pressure switch contacts with a multimeter, measuring inches of water column at the switch port, and evaluating inducer motor performance require tools and experience that most homeowners do not have. If basic visual inspection does not reveal an obvious cause, a qualified HVAC technician should complete the diagnosis.

Repair costs vary depending on the root cause. If the issue is simply a blocked vent or a damaged pressure hose, the cost may be relatively low, typically in the range of $75 to $200 for a service call and minor parts. If the pressure switch itself needs replacement, expect to pay somewhere in the range of $150 to $350 including labor. An inducer motor replacement is a more significant repair, often ranging from $400 to $700 or more depending on the specific model and local labor rates.