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Lennox · Air conditioner

E430 Inverter compressor startup fail (inverter code 26)

High severity

What the control is telling you

Compressor failed to start; unit stops. 10 times in 60 minutes = lockout. Inverter LED flash code 26 (red 2 flashes, green 6 flashes). S30/S40 thermostat alert code 430 (shown as E430 on the unit control display).

Applies to: Lennox communicating air conditioners incl. variable-capacity inverter units in S30/S40 smart thermostat systems

Likely causes

  • Refrigerant problem
  • Failed outdoor control or inverter

Test and repair steps

  1. Check refrigerant charge.
  2. Replace outdoor control board if needed.
  3. Replace inverter if needed.
  4. Clear by disconnecting power to the outdoor unit and restarting.
  5. Check inverter LEDs flash code 26 = red 2 flashes, green 6 flashes. Normal inverter LEDs with no fault: red ON, green OFF.

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Source: Lennox Residential Communicating Systems Alert Code Guide (V2) 100017 (3/2023), Table 2 Alert Codes and Troubleshooting, 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.