Indoor unit displays E1 and the air conditioner will not start or stops shortly after starting.

Safety first: Turn off the AC at the breaker and unplug (if plug-in type) before removing any covers. High voltage is present inside both indoor and outdoor units.

• Step 1 – Power reset: Turn off the breaker for 5–10 minutes, then restore power. Sometimes E1 is triggered by a transient communication error.
• Step 2 – Check wiring between units:
  • Remove the indoor unit front cover and access the terminal block where the interconnecting cable is connected (usually labeled 1–2–3 or L–N–S).
  • Verify that the wire colors and terminal numbers match exactly at both indoor and outdoor units.
  • Tighten all terminal screws. Look for burnt, melted, or corroded terminals.
  • Inspect the cable sheath along its run for cuts, rodent damage, or crushed sections.
• Step 3 – Verify supply voltage:
  • Use a multimeter (if qualified) to confirm correct voltage at the indoor unit and outdoor unit according to the rating label (e.g., 220–240 V).
  • Incorrect voltage or reversed live/neutral can cause communication errors.
• Step 4 – Inspect PCBs visually:
  • With power OFF, remove covers and look at the indoor and outdoor main PCBs.
  • Check for burnt components, bulged capacitors, or signs of water damage.
• When to call a technician: If wiring and voltage are correct but E1 persists, the indoor main PCB or outdoor main PCB is likely faulty and should be tested and replaced by a qualified technician.