HVACopediaLennox · Furnace
E115 Low 24 VAC
What the control is telling you
Control voltage is below range (normal range 18 to 30 volts). The control restarts once voltage recovers.
Applies to: EL296UHV(X) series furnaces (integrated control 103130-XX and 107045-XX)
Likely causes
- Overloaded transformer from power-robbing accessories
- Undersized transformer
- Low line voltage
Test and repair steps
- Measure 24 VAC at the control; it should be between 18 and 30 volts.
- Check line voltage feeding the transformer.
- Look for extra accessories drawing from the 24 V circuit.
- Check the 3 A 24 V circuit breaker in the control box.
- Install a larger VA transformer if the load is too high; code clears when voltage recovers.
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 ML180UHE
- Filter sizes by cabinet width · Lennox SL297NV
Models that show this code
34 models in EL296UHV, Lennox SL280UHV, Lennox ML180UHE, Lennox SL297NV
Other codes on the same units
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Source: Lennox EL296UHV(X) Unit Information / Service Literature, Table 5 Ignition Control 103130-XX Diagnostic Codes, p.33; Ignition Control 107045-XX Diagnostic Codes table, p.40. Summarized in our own words; check the original manual for your model.
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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.