Lennox EL296UHV Error Code E 273: Soft Lockout - Flame Failure
What Does Code E 273 Mean?
Error code E273 on the Lennox EL296UHV indicates a soft lockout caused by exceeding the maximum number of recycles, with the last recycle due to flame failure. The furnace successfully lit but repeatedly lost the flame signal during operation. After too many flame-loss events, the control board entered a soft lockout.
Each time the flame sensor loses its signal, the gas valve closes for safety and the system attempts to relight. When this cycle repeats too many times, the control determines there is a persistent issue and enters lockout. The lockout clears when a subsequent heat call finishes successfully.
The most common cause is a dirty flame sensor that is marginally detecting the flame — it works well enough to start but cannot maintain a consistent reading. You may also see E240 (low flame current) appearing before or alongside E273. The sensor develops a layer of oxidation and combustion residue that insulates it from the flame. Less commonly, a poor unit ground or intermittent gas pressure can cause this code.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Dirty flame sensor | Most common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- E273 returns after cleaning the flame sensor
- The flame sensor rod is cracked, warped, or visibly damaged
- The flame appears weak, yellow, or flickers during operation
- E240 (low flame current) continues to appear after cleaning
- You suspect a grounding problem or intermittent gas supply issue
Sources
- Unit Information - icomfort ENABLED EL296UHV(X) Series Units
✓ Verified against manufacturer service manual — March 2026