Indoor unit shows E6; compressor may not start or may shut down; sometimes accompanied by outdoor unit not responding.

Safety: Isolate power at the main breaker. Outdoor units contain high-voltage components; do not touch capacitors or power modules when energized.

Steps:

• 1. Confirm E5 vs E6: Some Airwell models differentiate between general communication (E5) and outdoor feedback (E6). Check the user manual for your exact model.
• 2. Inspect outdoor PCB area: Remove the outdoor unit service panel. Look for obvious damage: burnt components, insect nests, water ingress, or corrosion on the PCB.
• 3. Check connectors: Ensure all multi-pin connectors between the outdoor PCB, compressor, fan motor, and sensors are fully seated.
• 4. Verify grounding: Confirm that the outdoor unit is properly grounded and that the ground wire is securely attached. Poor grounding can cause communication noise.
• 5. Inspect low-voltage wiring: Follow the communication wires from the terminal block to the PCB. Look for breaks or loose plugs.
• 6. Power supply check (advanced): With a multimeter and appropriate safety precautions, a technician can verify that the outdoor PCB is receiving correct DC supply voltages. If missing, the PCB or internal power supply is faulty.
• 7. Replace outdoor PCB if necessary: If all wiring is intact and the PCB shows visible damage or fails power checks, replacement of the outdoor main PCB is indicated. This should be done by a qualified technician due to high-voltage and refrigerant-related risks.