Lennox EL296UHV Error Code E 180: Outdoor Air Temperature Sensor Failure
What Does Code E 180 Mean?
Error code E180 on the Lennox EL296UHV indicates that the outdoor air temperature sensor has failed, is shorted, or is reading outside the expected range. This sensor allows the furnace to adjust its operation based on outdoor conditions, but the furnace will continue to heat without it.
The control board monitors the resistance of the outdoor sensor and compares it to known temperature-resistance values. If the reading falls outside the acceptable range — typically due to a short circuit in the sensor or damaged wiring — the board flags E180. The error only appears for shorted or out-of-range conditions, not if the sensor is simply disconnected.
While this code does not prevent the furnace from heating your home, the system loses its ability to factor outdoor temperature into its operating decisions. A technician should compare the sensor's resistance to the temperature/resistance chart in the installation instructions and replace the sensor pack if it is out of specification.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Shorted or out-of-range outdoor temperature sensor | Most common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- The outdoor temperature sensor needs to be tested and replaced
- You want to restore outdoor temperature-based performance optimization
- You notice the furnace is not adjusting its output properly in extreme cold or mild weather
✓ Verified against manufacturer service manual — March 2026