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UH
(5300)
Current sensor error
• Abnormal if current sensor detects –1.5A
to 1.5A during compressor operation.
(This error is ignored in case of test run
mode.)
w This error is ignored in case of test run
mode.
• It’s abnormal for 38A the input current or
10 seconds continuous 34A or more.
1 Disconnection of compressor
wiring
2 Defective circuit of current
sensor on outdoor power
circuit board
3 Decrease of power supply
voltage
1 Correct the wiring (U·V·W phase) to
compressor. Refer to 10-9 (Outdoor power
circuit board).
2 Replace outdoor power circuit board.
3 Check the facility of power supply.
Error Code
Abnormal point and detection method
Case
Judgment and action
U8
(4400)
Outdoor fan motor
The outdoor fan motor is considered to be
abnormal if the rotational frequency of fan
motor is abnormal when detected during
operation.
Fan motor rotational frequency is abnormal
if;
• 100 rpm or below detected continuously
for 15 seconds at 20:[68˚F] or more
outside air temperature
• 50 rpm or below or 1500 rpm or more
detected continuously for 1 minute.
1 Failure in the operation of
the DC fan motor
2 Failure in the outdoor circuit
controller board
1 Check or replace the DC fan motor.
2 Check the voltage of the outdoor circuit
controller board during operation.
3 Replace the outdoor circuit controller
board. (when the failure is still indicated
even after performing the remedy 1
above.)
U9
(4220)
Overvoltage or voltage shortage and
synchronous signal to main circuit
Abnormal if any of followings are detected
during compressor operation;
• Decrease of DC bus voltage to 310V
• Instantaneous decrease of DC bus volt-
age to 200V
• Increase of DC bus voltage to
A12, 18, 24N : 420V
A30, 36, 42N : 400V
• Decrease of input current of outdoor unit
to 0.5A only if operation frequency is
more than or equal to 40Hz or compres-
sor
current is more than or equal to 5A.
• Abnormal power synchronous (zero
cross) signal
• PFC error (overcurrent) when the current
peak of input current increase A12, 18,
24N: 47A (peak)
1 Decrease of power supply volt-
age
2 Disconnection of compressor
wiring
3 Disconnection or loose con-
nection of CN52C
4 Defective PFC module of out-
door power board (A12, 18,
24N only)
5 Defective ACT module (A30,
36, 42N only)
6 Defective ACT module drive
circuit of outdoor power circuit
board (A30, 36, 42N only)
7 Disconnection or loose con-
nection of CNAF (A30, 36, 42N
only)
8 Defective 52C drive circuit of
outdoor noise filter circuit
board
9 Disconnection or loose
connection of CN5 on the
outdoor power circuit board
0 Disconnection or loose
connection of CN2 on the
outdoor power circuit board
1 Check the facility of power supply.
2 Correct the wiring (U·V·W phase) to com-
pressor. Refer to 10-9 (Outdoor power circuit
board).
3 Check CN52C wiring.
4 Replace outdoor power circuit board.
(A12, 18, 24N only)
5 Replace ACT module. (A30, 36, 42N only)
6 Replace outdoor power circuit board.
(A30, 36, 42N only)
7 Check CNAF wiring. (A30, 36, 42N only)
8 Replace outdoor noise filter circuit board.
9 Check CN5 wiring on the outdoor power
circuit board.
Refer to 10-9.
0 Check CN2 wiring on the outdoor power
circuit board.
Refer to 10-9.
UF
(4100)
Compressor overcurrent interruption
(When compressor locked)
Abnormal if overcurrent of DC bus or
compressor is detected within 30 seconds
after compressor starts operating.
1 Stop valve is closed.
2 Decrease of power supply
voltage
3 Looseness, disconnection or
converse of compressor wiring
connection
4 Defective compressor
5 Defective outdoor power board
1 Open stop valve.
2 Check facility of power supply.
3 Correct the wiring (U·V·W phase) to
compressor.
Refer to 10-9 (Outdoor power circuit board).
4 Check compressor.
Refer to 10-6.
5 Replace outdoor power circuit board.
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