HVACopediaLennox · Furnace
E291 Heat airflow below minimum
What the control is telling you
Heating airflow is restricted below minimum; 1-hour soft lockout.
Applies to: EL296UHV(X) series furnaces with integrated control 103130-XX only
Likely causes
- Dirty filter
- Duct restriction
- Blower performance problem
Test and repair steps
- Inspect the filter (should be checked monthly) and replace if dirty; oversized pressure drop from high-efficiency filters can trip the limit.
- Measure external static pressure heating speed must not exceed 0.8 in. w.c.
- Measure temperature rise (supply minus return) and confirm it is within the rating-plate range, adjusting blower heat speed (DIP 11-13) if needed.
- Check the blower wheel for debris and verify blower operation.
- Clears when a heat call completes successfully.
Settings for these units
Recommended filter size by cabinet width · EL296UHV
| Cabinet width | Side return | Bottom return |
|---|---|---|
| 17-1/2 in. | 16 x 25 x 1 in. (1) | 16 x 25 x 1 in. (1) |
| 21 in. | 16 x 25 x 1 in. (1) | 20 x 25 x 1 in. (1) |
| 24-1/2 in. | 16 x 25 x 1 in. (2) | 24 x 25 x 1 in. (1) |
Number in brackets is the quantity of filters.
Filters are field supplied and installed outside the furnace; inspect monthly.
Recommended filter size by cabinet width · Lennox SL280UHV
| Cabinet width | Side return | Bottom return |
|---|---|---|
| 14-1/2 in. | 16 x 25 x 1 in. (1) | 14 x 25 x 1 in. (1) |
| 17-1/2 in. | 16 x 25 x 1 in. (1) | 16 x 25 x 1 in. (1) |
| 21 in. | 16 x 25 x 1 in. (1) | 20 x 25 x 1 in. (1) |
| 24-1/2 in. | 16 x 25 x 1 in. (2) | 24 x 25 x 1 in. (1) |
Number in brackets is filter quantity; filters are field supplied.
Never run the unit without a filter installed.
- Filter sizes by cabinet width · Lennox SL297NV
Models that show this code
22 models in EL296UHV, Lennox SL280UHV, Lennox SL297NV
Other codes on the same units
Save it for the next call
Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.
Source: Lennox EL296UHV(X) Unit Information / Service Literature, Table 5 Ignition Control 103130-XX Diagnostic Codes, p.36. Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.