Lennox Error Code E112 indicates Ground not detected. 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
Ground not detected
System shuts down
Missing earth ground on system
Provide proper earth ground; system resumes normal operation 5 seconds after fault recovered
Grounding system
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: