Communication error
The indoor unit, outdoor unit or controller can no longer communicate, so the system stops or runs in a limited mode.
Common causes
- Communication wiring between indoor and outdoor unit disturbed
- Controller or wired remote disconnected
- Power interruption on one unit
- Control board fault
Safe checks
- 1Note whether the error appears on the indoor unit, the outdoor unit or the controller.
- 2Check both units have power.
- 3Restart using the manufacturer-documented procedure, such as switching off at the breaker for the stated waiting time.
- 4Do not open the outdoor unit — it contains mains and refrigerant components.
Related error codes
Brands commonly affected
When to call a technician
Call a qualified technician if the device repeats the fault after a manufacturer-approved restart, shows a burning smell, has damaged or discoloured wiring, or if the symptom involves the battery, inverter power stage or any sealed high-voltage component.