Panasonic CS-XZ20XKEW-H Service Manual page 113

18.4.2 H12 (Indoor/Outdoor Capacity Rank Mismatched)
Malfunction Decision Conditions

During startup, error code appears when different types of indoor and outdoor units are interconnected.
Malfunction Caused

Wrong models interconnected.

Wrong indoor unit or outdoor unit PCBs mounted.

Indoor unit or outdoor unit PCBs defective.

Indoor-outdoor unit signal transmission error due to wrong wiring.

Indoor-outdoor unit signal transmission error due to breaking of wire 3 in the connection wires between the indoor
and outdoor units.
Troubleshooting
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