Error Code: EL 01 – Indoor & Outdoor Unit Communication Error

Error Code: EL 01 – Indoor & Outdoor Unit Communication Error

What this means:
The indoor unit is not able to communicate with the outdoor unit. This can be caused by broken signal wires, improper shielding, electromagnetic interference, or a failure in the indoor or outdoor PCBTS20.

Try this first (quick reset):

1. Turn off power to the unit completely.

2. Wait 2 full minutes.

3. Turn it back on and observe the system.

• If the error clears — the connection may have reset.

• If it returns — follow the diagnostic steps below.

Next steps (for technicians):

1. Check for interference:

   • Are there nearby power transformers, large lighting systems, or long signal wires?

   • If so → use shielded cable and ensure it's properly grounded.

   • You may also need to add a magnet ring to the power cable to reduce interference.

2. Inspect the signal wire:

   • Is it shielded and grounded?

   • Is it broken or damaged?

   • If damaged → replace the signal wire.

3. Reconnect the signal cable:

   • Pull out and reinsert the connectors on both PCBs.

4. If still unresolved:

   • Replace the indoor main PCB first.

   • If the error remains → replace the outdoor main PCB.

What you might need:

• Signal wire (shielded)

• Magnet ring

• Indoor main PCB

• Outdoor main PCB

Helpful tip:
Electromagnetic interference is a common and often overlooked cause of EL 01. Using a properly shielded and grounded communication wire is critical for reliable system communication.

Click here to view the detailed guide.TS20