Lennox EL296UHV Error Code E 111: Line Voltage Polarity Reversed
What Does Code E 111 Mean?
Error code E111 on the Lennox EL296UHV indicates that the line voltage polarity is reversed. The control board has detected that the hot (line) and neutral power wires are connected in the wrong positions. The system will not operate normally until the wiring is corrected.
Reversed polarity is a wiring error where the 120-volt hot wire is connected where the neutral should be, and vice versa. This can happen during installation, after electrical panel work, or if the furnace is connected to a receptacle that was wired incorrectly. On the EL296UHV, proper polarity is required for the flame sensing circuit and other safety systems to function correctly.
The system resumes normal operation within 5 seconds after the polarity is corrected. This repair requires a qualified electrician or HVAC technician because it involves working with line-voltage wiring. The technician should verify polarity at the furnace disconnect and trace the circuit back to the panel if necessary.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Hot and neutral wires reversed at furnace connection | Most common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- The furnace displays E111 — an electrician needs to correct the wiring
- The polarity issue appeared after recent electrical work
- You are unsure which wire is hot and which is neutral
✓ Verified against manufacturer service manual — March 2026