Panasonic CU-E18CKR Service Manual page 42

8.2.2.3. Anti-Freezing Control
1. When indoor heat exchanger temperature is lower than 2°C
continuously for six minutes, compressor will stop operating.
2. Compressor will resume its operation three minutes after the
indoor heat exchanger is higher than 10°C.
3. At the same time, indoor fan speed increase +40 rpm compared to
its normal operation.
4. If indoor heat exchanger temperature is higher than 10°C for five
minutes, the fan speed will return to its normal operation.