Indoor unit does not respond to remote, display shows E0 and unit will not start cooling or heating.

Safety first: Turn off the air conditioner using the remote, then switch OFF the circuit breaker or disconnect the power plug. Wait at least 5 minutes before touching any internal parts.

• Step 1 – Power reset: Restore power after 5–10 minutes and try to start the unit again. Sometimes an E0 code clears after a full power reset.
• Step 2 – Check indoor front panel and display board: Remove the front cover of the Royal Clima indoor unit (usually two screws at the bottom and clips at the top). Verify the display/indicator board harness is firmly connected to the main PCB.
• Step 3 – Inspect wiring harness: Look for loose connectors, bent pins, or signs of burning on the connectors going to the EEPROM / memory IC area on the indoor PCB.
• Step 4 – Visual PCB inspection: Check the indoor main control board for burnt components, swollen capacitors, or darkened areas. If any are found, the board should be replaced, not repaired by a non‑professional.
• Step 5 – Try factory reset (if available): Some Royal Clima models allow a reset via the remote (e.g., press and hold MODE + POWER for 5 seconds). Refer to the user manual; if the reset does not clear E0, the PCB is likely faulty.

When to call a technician: If E0 persists after a power reset and connector check, the indoor PCB/EEPROM will usually need replacement and should be handled by an authorized Royal Clima service center.