18
Error Code
Abnormal point and detection method
Case
Judgment and action
U8
Outdoor fan motor
Abnormal if rotational frequency of the fan
motor is not detected during DC fan motor
operation.
Fan motor rotational frequency is abnor-
mal if;
• 100 rpm or below detected continuously
for 15 seconds at 20
:
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
UF
Compressor overcurrent interruption
(When compressor locked)
Abnormal if overcurrent of DC bus or
compressor is detected within 30 seconds
after compressor starts operating.
1
Decrease of power supply voltage
2
Looseness, disconnection or
converse of compressor wiring
connection
3
Defective compressor
4
Defective outdoor power board
5
Decreased water flow
6
Clogged filter of water pipe
7
Clogged plate heat exchanger
8
Locked water pump
9
Malfunction of water pump
1
Check facility of power supply.
2
Correct the wiring (U
•
V
•
W phase) to
compressor.
Refer to 8-6 (Outdoor power circuit board).
3
Check compressor. Refer to 8-4.
4
Replace outdoor power circuit board.
5
~
9
Check water circuit and repair the defect.
Ud
Overheat protection
Abnormal if outdoor pipe thermistor (TH3)
detects 70
:
or more or condensing
temperature of pressure sensor (63HS)
detects 70
:
or more during compressor
operation.
1
Defective outdoor fan (fan
motor) or short cycle of out-
door unit during cooling opera-
tion
2
Defective outdoor pipe
thermistor (TH3)
3
Defective outdoor controller
board
4
Defective pressure sensor
1
Check outdoor unit air passage.
23
Turn the power off and on again to check
the error code. If U4 is displayed, follow the
U4 processing direction.
4
Check pressure by microcomputer.
(Pressure sensor/ 63HS)
(SW2: Refer to 8-7.)
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 400V
• Decrease of input current of outdoor unit
to 0.1A only if operation frequency is
more than or equal to 40Hz or compres-
sor current is more than or equal to 6A.
* Check U9 error detail (SW2 all ON)
Refer to 8-7.
1
Decrease of power supply volt-
age
2
Disconnection of compressor
wiring
3
Defective power circuit board
4
Disconnection or loose connec-
tion of CN52C
5
Defective ACT module
6
Defective ACT module drive
circuit of outdoor power circuit
board
7
Disconnection or loose connec-
tion of CNAF
8
Defective 52C drive circuit of
outdoor controller 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 8-6 (Outdoor power circuit
board).
3
Replace power circuit board.
4
Check CN52C wiring.
5
Replace ACT module.
6
Replace outdoor power circuit board.
7
Check CNAF wiring.
8
Replace outdoor controller circuit board.
9
Check CN5 wiring on the outdoor power cir-
cuit board.
Refer to 8-6.
0
Check CN2 wiring on the outdoor power cir-
cuit board. Refer to 8-6.
