Panasonic CU-Z20VKE Series Installation Instruction page 133

18.4.20 F17 (Indoor Standby Units Freezing Abnormality)
Malfunction Decision Conditions

When the different between indoor intake air temperature and indoor pipe temperature is above 10°C or indoor
pipe temperature is below -1.0°C.
Remark:
When the indoor standby unit is freezing, the outdoor unit transfers F17 error code to the corresponding indoor
unit and H39 to other indoor unit(s).
Malfunction Caused

Wrong wiring connection

Faulty sensor

Faulty expansion valve
Troubleshooting
132