H4
Royal Clima Indoor–Outdoor Mismatch / Mode Conflict or EEPROM Error

Indoor unit shows H4, unit may not respond to mode changes or may shut down unexpectedly.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Incorrect combination of indoor and outdoor units, Faulty communication protocol between boards, Corrupted configuration data, Recently replaced PCB not configured correctly

How to Fix / Troubleshooting

Safety first: Disconnect power before opening any covers.

  • Step 1 – Power reset: Turn OFF the breaker for 10 minutes, then restore power.
  • Step 2 – Check model compatibility: If components were recently replaced, verify that indoor and outdoor units are compatible Royal Clima models.
  • Step 3 – Inspect communication wiring: Ensure all communication terminals are correctly wired and tight.

When to call a technician: H4 often requires service tools to reconfigure or update the PCB. Contact an authorized service center.

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Repair Difficulty

Hard 4/5

Required Part

Outdoor Main Control PCB
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