Lennox Error Code E274 indicates Soft lockout – exceeded maximum number of recycles; last recycle failed due to limit circuit opening or remaining open longer than 3 minutes. Start by checking the most common and safe items identified in the troubleshooting section. If the code returns after those checks, professional diagnosis is recommended.
Easy
Soft lockout – exceeded maximum number of recycles; last recycle failed due to limit circuit opening or remaining open longer than 3 minutes
Unknown
Limit circuit opened due to overheating or airflow issue
Shut down system; 1‑hour soft lockout; check firing rate and air flow; check for blockage; clears when heat call finishes successfully
Limit switch, airflow system (filters, blower), heat exchanger
Call an HVAC technician if the error persists after completing the recommended basic troubleshooting steps or if the system repeatedly locks out.
Disconnect power before inspecting the equipment. Never bypass safety devices or operate the system if you suspect unsafe conditions.
Learn more about the furnace components and operating conditions commonly associated with diagnostic error codes: