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F11

F11 (18 flashes) — Loss of synchronism detection

Haier · Air Conditioning

What does F11 mean?

The system is having trouble detecting the precise position of the compressor's rotor. This is critical for the compressor's smooth operation.

Common Causes

  • Incorrect compressor wiring
  • Poor compressor connection
  • Damaged compressor
  • Faulty PCB

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Turn off the power switch before checking any connections.

  2. 2

    Verify the compressor wiring is correct and connections are secure.

  3. 3

    Restart the unit.

  4. 4

    If the problem persists after checking wiring, the compressor or PCB may be faulty and require professional diagnosis.

Browse all codes in this manual (103)
Verified technical data. Last updated: April 2026

Related Faults

1Error Code 1 — Outdoor PCB EEPROM fault10Error Code 10 — Defrost sensor fault11Error Code 11 — Compressor suction temperature sensor fault
Source: Haier Air Conditioning
Open Manual (Page 31)Search more codes in this manual