58 
15.5.2  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 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Check the indoor and outdoor unit connection wires.
Check indoor and outdoor units model number.
Is indoor unit and outdoor unit model numbers matched?
Check the spare part numbers of the indoor and outdoor unit 
PCBs and compare with their Part Lists.
Matched compatibility?
Is there any wiring error?
When abnormality indication starts again.
For safety reason and to prevent
component breakdown, always switch 
off the power before remove and 
connect the component.
Correct the indoor-outdoor unit’s connection wires.
Change for the specified indoor or outdoor unit 
PCB.
Replace the indoor and outdoor unit PCBs.
Match the compatible model(s).
NO
NO
NO
YES
YES
YES
Caution