Remote controller signal receiving error (Indoor unit to Remote controller)

What does E4 mean?

The indoor controller board cannot receive any data normally from the remote controller or other indoor controller boards for 3 minutes (E4). This indicates a receiving communication problem within the indoor unit, potentially due to wiring issues, misconfiguration (all sub-controllers), or a defective transmitting/receiving circuit. This hinders the indoor unit's ability to process commands and coordinate with the system.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Verify remote controller wiring specifications, including total length (max. 500m) and number of connected units (max. 16 units, max. 2 controllers).

2. 4

   Perform a remote controller diagnosis. If 'RC NG' appears, replace the remote controller. If 'RC OK' but the error persists, replace the indoor controller board.

3. 5

   If 'RC E3' or 'ERC 00-06' is displayed, investigate and address potential noise interference on the transmission wire.