Lennox Furnace Error Code E 227

E 227 means the low pressure switch was detected in the open position during the trial for ignition or while the furnace was actively running. The low pressure switch must close to confirm that the inducer is creating adequate draft before and during combustion. When it does not close, the furnace shuts down as a safety measure. The fault clears and normal operation resumes automatically once the underlying issue is corrected.

Yes, but the safety system is working as intended when E 227 appears. The furnace is refusing to run because it cannot confirm proper venting conditions, which prevents the risk of combustion without adequate draft. You should not attempt to bypass or override the low pressure switch. Leave the furnace off until the root cause is repaired.

Repair cost depends entirely on what is causing the fault. Clearing a blocked vent termination may cost only a service call fee, typically in the range of $75 to $150. Replacing a low pressure switch generally runs $100 to $250 including parts and labor. An inducer motor replacement is a more significant repair and can range from $300 to $600 or more depending on the model and local labor rates.

Some causes of E 227 are accessible to a knowledgeable DIYer. Checking the vent termination for ice, debris, or blockage and inspecting visible pressure tubing for cracks or loose connections are reasonable first steps. However, measuring switch closing pressure with a manometer, testing the inducer motor and capacitor, and replacing components requires tools and experience that most homeowners do not have. If basic visual checks do not reveal an obvious problem, a qualified HVAC technician should complete the diagnosis.

According to Lennox, the furnace resumes normal operation automatically after the fault is cleared, meaning the underlying pressure issue must be resolved first. Simply cycling power or pressing a reset button without correcting the venting or inducer problem will result in E 227 returning as soon as the furnace attempts another heating cycle. Clearing the code is only meaningful after the root cause has been identified and fixed.