Lennox Error Code E223 indicates Low pressure switch failed open. 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
Low pressure switch failed open
Unknown
Low pressure switch does not close on heat call
Check pressure of low pressure switch closing on heat call; measure operating pressure; inspect vent and combustion air inducer for correct operation and restriction; resumes normal operation after fault cleared
Low pressure switch, vent system, combustion air inducer
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: