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U2

Outdoor Board LED1 (green) blinks three times and LED2 (red) blinks two times alternately - Abnormality of shell thermostat and discharging temperature (TH4)

MHI · Air Conditioning

Was bedeutet U2 ?

During startup or operation, the outdoor unit's LED1 (green) blinks three times and LED2 (red) blinks two times alternately, indicating an abnormality of the shell thermostat and/or discharge temperature sensor (TH4).

Häufige Ursachen

  • Abnormality of shell thermostat and discharging temperature (TH4).
  • Connectors (TH4, LEV-A, and LEV-B) on outdoor controller board are disconnected.
  • Insufficient refrigerant in the unit.

Reparaturschritte & Checkliste

Klicken Sie auf Schritte, um Ihren Fortschritt zu verfolgen.

  1. 1

    Check if connectors (TH4, LEV-A, and LEV-B) on the outdoor controller board are not disconnected.

  2. 2

    Measure resistance values among terminals on indoor valve and outdoor linear expansion valve using a tester.

  3. 3

    Check if the unit is filled with the specified amount of refrigerant.

  4. 4

    Ensure the shell thermostat is properly seated and functioning.

Alle Codes in diesem Handbuch durchsuchen (124)
Verifizierte technische Daten. Zuletzt aktualisiert: April 2026

Verwandte Fehlercodes

00Outdoor Board LED only green lights up after startup - No outdoor unit of address 0 / Remote controller transmission wire open1OPERATION INDICATOR lamp blinks 1 time (Pattern A) - Indoor/outdoor unit communication error (Transmitting error - Outdoor unit)14OPERATION INDICATOR lamp blinks 14 times (Pattern A) - Other errors
Quelle: MHI Air Conditioning
Open Manual (Page 60)Mehr Codes in diesem Handbuch suchen