What does error code 291 mean on a thermostat?
FAQ , Thermostats , Troubleshooting Modified: March 19, 2026
Based on a recent interaction with a similar issue, error code 291 on a thermostat indicates that the furnace airflow is below the required level. this issue is hardware related and would need to be looked at by an hvac professional. if you're experiencing this error, i would recommend reaching out to a professional for assistance. if you need help locating a dealer, you can visit the lennox website.
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