Indoor unit shows E5 and stops; sometimes the outdoor unit does not start at all.

Safety first: Switch OFF the main breaker before opening any electrical covers.

• Step 1 – Check household voltage stability: If lights flicker or other appliances reset frequently, contact an electrician to check the supply. Royal Clima units may show E5 when voltage is outside the safe range.
• Step 2 – Inspect power terminals: Open the indoor and outdoor electrical covers and verify that all L, N, and ground wires are tight and not discolored or burnt.
• Step 3 – Use a voltage stabilizer (if recommended): In areas with unstable power, use a properly sized voltage stabilizer or surge protector approved for air conditioners.
• Step 4 – Power reset: Turn OFF the breaker for 10 minutes, then restore power and test again.

When to call a technician: If E5 persists with stable mains voltage, the power filter board or inverter module may be faulty and should be tested and replaced by a professional.