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16.4.19 H99 (Indoor Freeze Prevention Protection: Cooling or Soft Dry)
Error Code will not display (no Timer LED blinking) but store in EEPROM
Malfunction Decision Conditions
Malfunction Decision Conditions
Freeze prevention control takes place (when indoor pipe temperature is lower than 2°C)
Malfunction Caused
Air short circuit at indoor unit
Clogged indoor unit air filter
Dust accumulation on the indoor unit heat exchanger
2/3 way valve closed
Faulty indoor unit fan motor
Refrigerant shortage (refrigerant leakage)
Clogged expansion valve or strainer
Faulty indoor pipe temperature sensor
Faulty indoor unit PCB
Troubleshooting
94
16.4.20 F11 (4-way valve Abnormality)
Malfunction Decision Conditions
When heating operation, when indoor pipe temperature is below 10°C
When cooling operation, when indoor pipe temperature is above 45°C
Malfunction Caused
Connector in poor contact
Faulty
sensor
Faulty outdoor unit PCB
4-way valve defective
Troubleshooting
95
16.4.21 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).
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
96
16.4.22 F90 (Power Factor Correction Protection)
Malfunction Decision Conditions
During startup and operation of cooling and heating, when Power Factor Correction (PFC) protection circuitry at
the outdoor unit main PCB senses abnormal high DC voltage level.
Malfunction Caused
DC voltage peak due to power supply surge.
DC voltage peak due to compressor windings not uniform.
Faulty outdoor PCB.
Troubleshooting
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