FAILURE
CODE
STATE OF
LED 5-4-3-2-1
TROUBLE
SHOOTING
POSSIBLE REASONS
1
Faulty defrost sensor
Te
Sensor disconnected, or broken, or short circuit
Faulty sensor
Tao
Sensor disconnected, or broken, or short circuit
Faulty sensor
Ts
Sensor disconnected, or broken, or short circuit
Faulty sensor
Td
Sensor disconnected, or broken, or short circuit
Input overcurrent
Over current of the system, or broken of the current
sensor,or malfunction with indoor or outdoor fan
motors, or faulty PCB.
Abnormal communication
between indoor and outdoor
units
Wrong connection, or the wires be disconnected, or
wrong address setting of indoor units, or faulty PCB,
or faulty power supply
2
3
4
5
6
System high pressure
protection
High pressure switch is disconnected, or high
pressure switch worked, or Tc too high and faulty
outdoor fan motor when cooling, or faulty indoor fan
motors when heating, or refrigerant overabundance
9
System low pressure
protection
Low pressure switch is disconnected, or low
pressure switch worked, or Te too low and faulty
outdoor fan motors when heating, or faulty indoor
fan motor when cooling, or refrigerant shortage
10
IPM protection
IPM over current, or short circuit, or IPM
temperature too high, or IPM input voltage too
low,or faulty SPDU.
EEPROM fault
Faulty outdoor unit PCB
Over hot protection of
compressor
Serious lack of refrigerant of the system, or the
ambient temperature too high, or PMVs be
blocked
DC fan motor fault
Fan is blocked, or the terminal is disconnected
from the PCB
Faulty 4-way valve
switching on
Coil of 4-way valve is disconnected, or faulty
outdoor PCB
Faulty sensor
Tc
Sensor disconnected, or broken, or short circuit
Faulty sensor
Toci
Sensor disconnected, or broken, or short circuit
Abnormal communication
between main PCB and
SPDU
Communication cables broken, or not be well
connected, or faulty main PCB, or faulty SPDU
Compressor locked rotor
Faulty compressor or SPDU
Compressor heavy vibration Faulty compressor
Compressor lose position
Faulty SPDU
Faulty compressor start
Faulty compressor or SPDU
Faulty position checking
circuit
Faulty SPDU
Compressor broken
Faulty compressor or SPDU
Take off the plastic valve cover, you can find the LEDs near to the communication terminal.
Symbol means the LED is ON. Symbol means the LED is OFF.
11
12
13
15
16
17
21
25
26
27
28
29
30
31
Outdoor trouble shooting
Commercial Air Conditioner
Model: AU18
/22
2XFERA
AS072/092/122XVERA
-60-