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A4

A4 - Malfunction of freezing protection

Daikin · Air Conditioning

What does A4 mean?

The system has activated freezing protection. This is often due to insufficient airflow over the indoor coil.

Common Causes

  • Dirty air filters
  • Blocked indoor unit vents
  • Low ambient temperature

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Clean or replace the air filters.

  2. 2

    Make sure the indoor unit's air intake and outlet are clear of obstructions.

  3. 3

    Avoid running the unit in extreme low temperatures if it's not designed for it.

Browse all codes in this manual (79)
Verified technical data. Last updated: April 2026

Related Faults

A0A0 - External protection activeA1A1 - Indoor PCB failureA2A2 - Malfunction of freezing protection
Source: Daikin Air Conditioning
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