Lennox EL296UHV Error Code C: Cooling Stage
What Does Code C Mean?
When the icomfort system calls for cooling, the SureLight integrated control lights "C" on the seven-segment display (about 1 second on, half a second off), then cycles through the active cooling stage number (1 or 2) and the blower CFM before pausing and repeating. Although the EL296UHV is a gas furnace, its control also runs the indoor blower for the paired air conditioner or heat pump during cooling, which is why a heating appliance shows a cooling status.
The stage digit reflects two-stage cooling: stage 1 is low-capacity cooling for mild loads, and stage 2 is full capacity for hot days. The variable-speed ECM blower ramps its CFM to match the selected cooling stage, and that airflow is the number shown after the stage digit.
This ties to the other mode letters on the same board: an uppercase "H" for gas heat, a lowercase "h" for heat-pump heat, and "d" for dehumidification. Seeing "C" simply tells you the furnace's blower is serving a cooling call.
What You'll Notice
- The display cycles "C", then a 1 or 2, then a CFM number, pausing and repeating while the air conditioner runs.
- Cool air comes from the vents and the indoor blower runs, while the burners and inducer stay off.
How This Is Diagnosed
The "C" sequence confirms the board received a cooling call and shows which stage and CFM it is running, so reading it verifies normal cooling operation. It would only matter if "C" shows while the outdoor unit is not actually cooling, which suggests a thermostat or wiring configuration issue rather than a furnace fault.
- The display shows "C" and runs the blower, but no cold air is produced and the outdoor condenser never starts.
- The cooling stage stays on 1 and never steps to 2 on the hottest days, leaving the home warm.
Frequently Asked Questions
Why does my gas furnace show a cooling code?
The furnace's control board also runs the indoor blower for your air conditioner. "C" simply reports that a cooling call is active and which stage and airflow the blower is using.
What do the 1 and 2 after "C" mean?
They are the cooling stage: 1 for low-capacity cooling on mild days and 2 for full-capacity cooling on hot days, matched to your two-stage cooling equipment.
✓ Verified against manufacturer service manual — March 2026