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435

Alert Code 435 — EEPROM checksum fault

Lennox · Communicating Systems

What does 435 mean?

An internal error has been detected within the inverter's memory (EEPROM). The system will attempt to reset the inverter by cycling its power. If the problem continues, the outdoor unit will stop operation.

Common Causes

  • Inverter internal error
  • EEPROM checksum failure

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Disconnect power to the outdoor unit.

  2. 2

    Reconnect power to the outdoor unit and restart the system.

Browse all codes in this manual (41)
Verified technical data. Last updated: April 2026

Related Faults

14Inverter Flash Code 14 (Red 1 flash, Green 4 flashes) — OD Inverter Compressor Slowdown21Inverter Flash Code 21 (Red 2 flashes, Green 1 flash) — OD Inverter DC Peak Fault262 red flashes, 6 green flashes — Compressor startup fail
Source: Lennox Communicating Systems
Open Manual (Page 63)Search more codes in this manual