Indoor unit shows F4, unit may stop in both cooling and heating modes.

Safety first: Turn OFF power and allow the outdoor unit to cool down before touching any pipes.

• Step 1 – Locate discharge sensor: Find the sensor attached to the small-diameter copper pipe leaving the compressor.
• Step 2 – Check mounting: Ensure the sensor is tightly strapped or clipped to the pipe with insulation over it.
• Step 3 – Inspect wiring: Follow the sensor wires to the outdoor PCB and check for damage or loose connectors.
• Step 4 – Replace if necessary: Install a new Royal Clima discharge sensor if the old one is cracked or corroded.

When to call a technician: Persistent F4 after sensor replacement indicates a PCB fault or abnormal discharge temperatures that require professional diagnosis.