40
Error Code
Meaning of error code and detection method
Judgment and action
U3
(5104)
Open/short circuit of discharging
(compressor surface) thermistor (TH4)
Abnormal if open (0
:
or less) or short
(216
:
or more) is detected during
compressor operation.
(Detection is inoperative for 5 minutes of
compressor starting process and for 10
minutes after defrosting.)
1
Disconnection or contact fail-
ure of connector (TH4) on the
indoor controller board
2
Defective thermistor
3
Defective outdoor controller
board
1
Check contact of connector (TH4) on the
indoor controller board.
Refer to 11-7
Check breaking of the lead wire for thermistor
(TH4). Refer to 11-6
2
Check resistance value of thermistor
(Refer to 11-6.), or check temperature by
microprocessor (Mode switch of SW2).
3
Replace outdoor controller board.
U4
(5105)
(5107)
Open/short circuit of the liquid pipe
thermistor (TH3) or outdoor Condenser-
Evaporator pipe thermistor (TH6)
Abnormal if open (-39
:
or less) or short
(88
:
or more) is detected during compres-
sor operation.
(Detection is inoperative for 7 minutes after
10 seconds of compressor starting and for
10 minutes after defrosting.)
1
Disconnection or contact failure
of connector (TH3/TH6) on the
indoor controller board
2
Defective thermistor
3
Defective outdoor controller
board
1
Check contact of connector (TH3/TH6) on
the indoor controller board.
Refer to 11-7.
Check breaking of the lead wire for thermistor
(TH3/TH6). Refer to 11-6.
2
Check resistance value of thermistor
(Refer to 11-6.), or check temperature by
microprocessor (Mode switch of SW2).
3
Replace outdoor controller board.
U6
(4101)
Compressor over current (overload)
breaking
Abnormal if current value exceeds overload
set value during compressor operation.
P71V
• • •
23.5A P71Y
• • •
7.8A
P100V
• • •
28.5A P100Y
• • •
9.4A
P125Y
• • •
12.6A P140Y
• • •
15.6A
1
Gas pipe side ball valve and
liquid pipe side stop valve are
shut during operation.
2
Abnormal compressor
3
Abnormal power supply voltage
4
Overload operation
1
Open ball valve and stop valve.
2
Check or replace compressor.
Refer to 6-2.
3
Check power supply voltage.
4
Check short cycle.
Ud
(1504)
Over heat protection (over-load opera-
tion protection/abnormal fan)
Abnormal if pipe thermistor detects the
value that exceeds set value during com-
pressor operation.
P71-P140
• • •
70
:
1
In cooling mode: defective
outdoor fan (fan motor) or
short cycle of air path
2
Defective thermistor
3
Defective outdoor controller
board
1
Check outdoor fan (fan motor)
Refer to 11-6.
24
Turn the power off and operate again to
check if U4 is displayed.
If U4 is displayed, follow the U4 processing
direction.
UE
(1302)
Abnormal High pressure
This error is detected (4.14MPa) from
63H action within 20 seconds of compres-
sor starting in the first heating mode after
power on.
63H: high-pressure switch
1
Gas pipe side ball valve and
liquid pipe side stop valve are
shut during operation.
2
Disconnection or contact failure
of 63H
3
Defective outdoor controller
board
4
Power supply reset is detected
while indoor filter clogs and
overload heating operation.
5
Defective outdoor controller
board
6
Defective action of linear
expansion valve
1
Open ball valve and stop valve.
23
Turn the power off, and operate again to
check if F5 is displayed.
If F5 is displayed, follow the F5 processing
direction.
4
Check indoor filter.
5
Replace outdoor controller board.
6
Check linear expansion valve.
Refer to 11-6.
Case
UL
(1300)
Abnormal low pressure (63L worked)
Abnormal if connector (63L) is open (under-
0.03MPa) during compressor operation.
1
Gas pipe side ball valve and
liquid pipe side stop valve are
shut during operation.
2
Disconnection or contact fail-
ure of connector (63L) on out-
door controller board
3
Disconnection or contact fail-
ure of 63L
4
Defective outdoor controller
board
5
Leakage or defective of refrig-
erant
6
Defective action of linear
expansion valve
1
Open ball valve and stop valve.
234
Turn the power off and on again to check
if F3 is displayed on restarting.
If F3 is displayed, follow the F3 process-
ing direction.
5
Leakage or defective of refrigerant
6
Check linear expansion valve
Refer to 11-6.
UA
(4101)
Thermal relay (51C) worked
Abnormal if 51C is open.
1
Ball valve and stop valve are
closed during operation.
2
Abnormal compressor
3
Abnormal power supply volt-
age
4
Short interruption.
1
Open ball valve and stop valve.
2
Check or replace compressor.
Refer to 6-2.
3
,
4
Check power supply voltage.
OC379F
