E223
Lennox
Equipment Configuration / Identification Error
Furnace does not respond to thermostat; E223 displayed on Lennox communicating thermostat; may indicate incorrect equipment configuration.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Incorrect equipment type selected in thermostat setup, Miswired ABCD communication bus, Incompatible Lennox furnace model with current thermostat, Faulty Lennox control board ID module
How to Fix / Troubleshooting
Safety: Turn off power to the furnace before changing wiring.
- 1. Verify ABCD wiring: On Lennox communicating systems, ensure the ABCD terminals on the furnace control and thermostat match color-for-color and letter-for-letter. Do not cross wires.
- 2. Confirm equipment setup: Enter the thermostat installer menu and verify the furnace type, stages, and gas/electric configuration match the actual Lennox furnace model number.
- 3. Check for added devices: If a new accessory (humidifier, zoning panel, etc.) was recently added, confirm it is wired correctly and supported by the system.
- 4. Power cycle: After corrections, power the furnace OFF for 60 seconds, then ON, and allow the thermostat to re-detect equipment.
If E223 remains, a Lennox technician may need to replace or reprogram the control board or thermostat.
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Repair Difficulty
Medium
3/5
Required Part
Lennox Integrated Furnace Control Board
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