Panasonic CS-S9TKV Service Manual page 114

15.4.18 H99 (Indoor Freeze Prevention Protection: Cooling or Soft Dry)
Malfunction Decision Conditions

Freeze prevention control takes place (when indoor pipe temperature is lower than 2°C)
Malfunction Caused

Clogged air filter of the indoor unit.

Dust accumulation on the indoor unit heat exchanger.

Air short circuit.

Detection error due to faulty indoor pipe temperature sensor.

Detection error due to faulty indoor unit PCB.
Troubleshooting
When abnormality indication starts again
Check the air passage
Is there any short circuit?
Check the air filter
Is the air filter dirty?
Check the dust accumulation on the indoor unit heat
exchanger
Is the indoor unit heat exchanger dirty?
Check the indoor heat exchanger temperature
sensor
Does it conform to the sensor characteristic chart?
YES
NO
YES
NO
YES
NO
NO
YES
114
For safety reason and to prevent
component breakdown, always switch
Caution off the power before remove and
connect the component.
● Provide sufficient air passage
● Clean the air filter
● Clean the indoor unit heat
exchanger
● Replace the indoor unit PCB
● Defect in indoor unit PCB
● Replace the indoor unit PCB