Error code
04 Indoor-to-outdoor communication and wiring fault
Applies to 4 models
RAS-25PKVSG-ND, RAS-35PKVSG-ND, RAS-25PAVSG-ND, RAS-35PAVSG-ND
What this means
The indoor-to-outdoor serial communication signal is absent or abnormal. Possible causes include defective or miswired interconnection cable, missing return signal, protection activation, or a failed signal circuit.
When to call a technician
This fault involves refrigerant, pressure, or electrical work that must be handled by a certified technician under EU F-gas rules. Do not attempt to open the refrigerant circuit, access mains wiring, or adjust pressure components yourself. Contact a qualified installer or servicer for this one.