105
F96 Transistor module
over-temperature
protection
Overheat is detected in the IPM to block the heat. The diagnosis code is stored in the
memory and the compressor stops. The error code is displayed if this error is detected
four times within 30 minutes.
<Points of diagnosis>
1. Interrupted heat radiation on the outdoor unit and the failure of outdoor unit fan. (The
outdoor unit fan does not rotate.)
2. Failure of IPM (outdoor unit control board).
3. Check for short-circuit and continuity of IPM sensor.
Interrupted heat
radiation
Outdoor unit fan
motor failure
Overload
conditions
F97 Compressor over-
temperature
protection
When the temperature of the compressor exceeds 103°C, the diagnosis code is stored
in the memory and the compressor stops. It resumes operation after 180 seconds when
the temperature is 92°C or below. The error code is displayed if this error is detected
four times within 20 minutes.
<Points of diagnosis>
1. Check of refrigerating cycle: Gas leak (Low refrigerant level).
Symptom: The outdoor unit sometimes stops.
2. The compressor temperature sensor is checked when the error code is displayed
and the compressor stops. (Check for change in characteristic and resistance value.)
3. Interrupted heat radiation on the outdoor unit and the failure of outdoor unit fan. (The
unit fan does not rotate due to open state.) (The error is sometimes detected in case
of overload. In this case, F97 remains in the memory.)
Low refrigerant
level (relatively
low)
Interrupted heat
radiation
Overload
conditions
F98 Total current
protection
If the total current exceeds the preset value, this diagnosis code is stored in the memory
and the compressor stops. It resumes operation after 180 seconds. The error code is
displayed if this error is detected three times within 20 minutes. [Refer to “Total Current
Protection Control” for the preset value]
<Points of diagnosis>
1. AC voltage of the outdoor unit terminal board during operation: The voltage should
drop by less than 5% from the voltage at the STOP state. (The rated voltage is to be
±110% even during the operation.) If the voltage drops by not less than 5%, or in
case of sudden change in voltage, check for the length/thinness of the indoor wiring
and indoor/outdoor connection wire.
2. Check for the interrupted heat radiation on the outdoor unit (during cooling
operation): The outdoor unit is usually not stopped and only subjected to the
capacity restriction by way of current control. No diagnosis code is displayed.
High refrigerant
level
Interrupted heat
radiation
F99 DC peak operation
error
When overcurrent, overheat or drop in supply voltage is detected in the IPM within 30
seconds from the start of the compressor, the compressor stops and then resume
operation in 60 seconds. When the error is detected seven consecutive times, the
compressor stops operation and the error code is displayed.
<Points of diagnosis>
1. The compressor stops under F99 within 30 seconds from its start:
When the lead wires are disconnected from U, V and W on the IPM then operate:
If F93 is displayed and the compressor stops: Check of refrigerating cycle, 3-
way valve opening failure, clogged pipe, failure of compressor (disconnection of
coil).
If F99 is displayed and the compressor stops: Check for IPM power supply of
DC15V (4 locations) and voltage of DC280V. Failure of outdoor unit control
board.
2. If the compressor stops after it operates for more than 5 minutes, a failure of the
power circuit and refrigerant cycle is also checked.
Compressor
Outdoor unit control
board
[Examples of the How to Identify the Faulty Point]
The following is some flow charts which illustrate on how to identify the faulty point for each code (examples).
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