Panasonic CS-RE18NKE Service Manual page 62

15.5.12 H98 (Indoor High Pressure Protection)
Error Code will not display (no Timer LED blinking) but store in EEPROM
Malfunction Decision Conditions
During heating operation, the temperature detected by the indoor pipe temperature sensor is above 60°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
62