15
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Troubleshooting
Installer reference guide
68
3AMXF-A9, 3AMXF-A9, 3AMXM-N9
R32 Split series
4P600463-1F – 2022.05
15.4 Solving problems based on LED behaviour
15.4.1 Fault diagnosis using LED on outdoor unit PCB
DANGER: RISK OF ELECTROCUTION
▪
When the unit is NOT operating, the LEDs on the PCB are turned OFF in order to
save power.
▪
Even when the LEDs are OFF, the terminal block and the PCB may be powered.
Symbol
LED is...
ON
OFF
Flashing
Red LED
(a)
Diagnosis
1
2
3
4
5
Normal.
▪
Check the indoor unit.
High-pressure protector worked or freeze-up in operating
unit, or stand-by unit.
Overload relay worked or high discharge pipe
temperature.
(b)
Faulty compressor start.
Input over-current.
Thermistor or CT abnormality.
(b)
High temperature switch box.
High temperature at inverter circuit heat sink.
Output over-current.
(b)
Refrigerant shortage.
(b)
Low voltage to main circuit or over voltage to main circuit.
Reversing solenoid valve switching failure or high-pressure
switching failure.
(b)
Faulty outdoor unit PCB.
Fan motor fault.
Wiring error
▪
Check wiring.
(a)
The number of LEDs displayed depends on the number of rooms.
(b)
Diagnosis may not apply to some cases. For more details, refer to the service manual.
Green LED-A
Diagnosis
Normal.
▪
Check the indoor unit.