20
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 action
1
above.)
U9
Overvoltage or voltage shortage and
synchronous signal to main circuit
Abnormal if any of followings are detected
during compressor operation;
•
Instantaneous decrease of DC bus voltage
400V
•
Increase of DC bus voltage to 760V
• Decrease of input current of outdoor unit
to 0.1A only if operation frequency is more
than or equal to 40Hz or compressor cur-
rent is more than or equal to 6A.
* Check U9 error detail (SW2 all ON).
Refer to 8-8.
1
Decrease of power supply
voltage
2
Disconnection of compressor
wiring
3
Disconnection or loose con-
nection of CN5 on the outdoor
power circuit board
4
Disconnection or loose con-
nection 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 8-7 (Outdoor power circuit
board).
3
Check CN5 wiring on the outdoor power
circuit board. Refer to 8-7.
4
Check CN2 wiring on the outdoor power
circuit board. Refer to 8-7.
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
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 8-7 (Outdoor power circuit board).
4
Check compressor.
Refer
to
8-5
.
5
Replace outdoor power circuit board.
Ud
Overheat protection
Abnormal if outdoor pipe thermistor (TH3),
condensing temperature T
63HS
detects 70
:
or more during compressor operation.
1
Defective outdoor fan (fan
motor) or short cycle of outdoor
unit during cooling operation
2
Defective outdoor pipe
thermistor (TH3), condensing
temperature T
63HS
3
Defective outdoor controller
board
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.
UE
Abnormal pressure of pressure sensor
(63HS)
Abnormal if pressure sensor (63HS)
detects 0.1 MPa or less.
Detection is inoperative for 3 minutes after
compressor starting and 3 minutes after
and during defrosting.
1
Disconnection or contact fail-
ure of connector (63HS) on the
outdoor controller circuit board
2
Defective pressure sensor
3
Defective outdoor controller cir-
cuit board
1
Check connection of connector (63HS) on
the outdoor controller circuit board.
Check breaking of the lead wire for thermis-
tor (63HS).
2
Check pressure by microcomputer.
(Prssure sensor/ 63HS)
(SW2: Refer to 8-8.)
3
Replace outdoor controller board.
