Indoor unit shows E5 and the compressor does not run; sometimes accompanied by outdoor unit clicking.

Safety first: Turn off the main breaker. High voltage and high current are present in the outdoor unit.

• Step 1 – Check supply voltage: Have a qualified person verify that the supply voltage at the outdoor unit terminals matches the rating label (e.g., 220–240 V). Low or fluctuating voltage can trigger E5.
• Step 2 – Inspect wiring: With power off, tighten all terminal screws in the outdoor unit and indoor-outdoor interconnect block. Look for burnt wires or discoloration.
• Step 3 – Test compressor windings: A technician should use a multimeter to measure resistance between compressor terminals and to ground. Shorted or open windings indicate a failed compressor.
• Step 4 – Check outdoor PCB: If the compressor tests good, the outdoor main PCB may be misreading current and should be tested and replaced if necessary.
• Note: Compressor replacement is a major repair and usually requires a professional with proper tools and refrigerant handling certification.