HVACopedia

Lennox · Furnace

1 flash Line voltage polarity reversed

Medium severity Lennox EL195UHNE

What the control is telling you

The control sees hot and neutral reversed (107163-01: reversed polarity or phasing of 120 V power). Heat will not run; cooling continues.

Applies to: EL195UHNE furnaces with ignition control 103217-03 or 107163-01 (red LED)

Likely causes

  • Hot and neutral swapped at the furnace or in the supply circuit

Test and repair steps

  1. Warning: Turn off power before rewiring.
  2. Check that line hot (black) lands on L1/LINE and neutral (white) on N; the furnace electronics are polarity sensitive.
  3. Check the house wiring/receptacle feeding the furnace for reversed polarity.
  4. Correct the wiring and restore power.

Settings for these 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.

Open the app

Source: Lennox EL195UHNE Unit Information Corp 1801-L1 (rev 04/2024), Table 4 (103217-03) / Table 5 (107163-01) diagnostic codes, p.8-10; flowchart p.51. 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.