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73

7 red flashes, 3 green flashes — PFC input over-current

Lennox · Communicating Systems

What does 73 mean?

The power factor correction (PFC) circuit in the inverter has detected an over-current condition. This might be due to high system pressure or a fan issue. The system will attempt to reset after a few minutes. If it happens too often, the system will lock out.

Common Causes

  • PFC circuit over-current detected
  • High system pressure
  • Outdoor fan failure

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the thermostat and outdoor control for other alert codes indicating high pressure.

  2. 2

    Moderate conditions should clear automatically. For critical conditions, power cycle the inverter.

  3. 3

    Ensure the outdoor unit fan is operating correctly and not obstructed.

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 64)Search more codes in this manual