Lennox Error Code E206 indicates Gas‑valve second‑stage relay failure. 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
Gas‑valve second‑stage relay failure
Furnace will operate on first stage only
Gas valve second‑stage relay failure
Furnace will operate on first stage for remainder of heating demand; replace control if second stage cannot operate
Gas valve second‑stage relay, control board
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: