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U0

U0 - Shortage of refrigerant (Outdoor Unit)

Daikin · Simple Self Diagnosis by Malfunction Code | Daikin

What does U0 mean?

The system is indicating a shortage of refrigerant, which could be due to a leak or low charge.

Common Causes

  • Refrigerant leak
  • Insufficient refrigerant
  • Faulty sensor

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Turn off the unit.

  2. 2

    Check for visible signs of oil leaks on refrigerant lines.

  3. 3

    Restore power and see if the error clears.

  4. 4

    If the error code returns, contact a technician for a refrigerant check.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

6-06-0 - External protection device activated (Heat reclaim ventilator)6-16-1 - Malfunction of PCB (Heat reclaim ventilator)6-26-2 - Ozone density abnormal (Heat reclaim ventilator)
Source: Simple Self Diagnosis by Malfunction Code | Daikin
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