Panasonic CS-E18NKUA Service Manual page 56

15.4.10 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 140.0°F.
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
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