Indoor unit stops and displays E1; unit may not respond to remote or buttons

Safety first: Turn off the air conditioner at the breaker and wait at least 5 minutes before removing any covers. Use an insulated screwdriver and avoid touching live terminals.

Steps to check:

• 1. Power reset: Turn the breaker OFF for 5–10 minutes, then back ON. Try operating the unit again. Sometimes E1 is a transient communication error.
• 2. Inspect communication cable: Remove the indoor unit front cover and access the terminal block where the interconnecting cable from the outdoor unit connects (usually labeled L, N, S or 1, 2, 3). Check that all screws are tight and no wires are burnt, loose, or corroded.
• 3. Verify correct wiring order: Compare the terminal labeling on the indoor and outdoor units. Ensure the same wire color goes to the same terminal number/letter on both ends. Incorrect wiring can cause E1.
• 4. Check cable condition: Follow the cable route between indoor and outdoor units. Look for rodent damage, cuts, crushed insulation, or signs of water ingress. Replace the cable if damaged.
• 5. Inspect PCBs (visual only): With power still OFF, remove the outdoor unit service panel and visually inspect the main PCB for burn marks, swollen capacitors, or melted connectors. Do the same for the indoor PCB. Do not touch or desolder components unless you are qualified.

When to call a technician: If wiring is correct and intact but E1 persists, the indoor or outdoor main PCB may be defective and should be tested and replaced by a qualified technician.