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Tanya LeeAug 21, 2025
Why is my Panasonic WH-SXC09D3E5 Heat Pump showing Indoor/Outdoor Abnormal Communication (H90)?
- KKatherine BlairAug 22, 2025
An Indoor/Outdoor Abnormal Communication (H90) error on your Panasonic Heat Pump may be due to several reasons: * A faulty outdoor or indoor unit PCB (main). * Indoor-outdoor signal transmission error due to wrong wiring. * A break in the connection wires between the indoor and outdoor units. * A disturbed power supply waveform. The system checks the data received from the outdoor unit during indoor unit signal transmission to ensure it is normal.