28
OCH754A
<Abnormalities detected while unit is operating>
Abnormal point and detection method
Judgment and action
U1
(1302)
High pressure (High pressure switch
63H worked)
Abnormal if high pressure switch 63H
worked (*) during compressor operation.
*4.15 MPa [602PSIG]
63H: High pressure switch
1
Short cycle of indoor unit
2
Clogged filter of indoor unit
3
Decreased airflow caused by
dirt of indoor fan
4
Dirt of indoor heat exchanger
5
Locked indoor fan motor
6
Malfunction of indoor fan motor
7
Defective operation of stop
valve (Not full open)
8
Clogged or broken pipe
9
Locked outdoor fan motor
0
Malfunction of outdoor fan
motor
1
Short cycle of outdoor unit
2
Dirt of outdoor heat exchanger
3
Decreased airflow caused by
defective inspection of outside
temperature thermistor
(It detects lower temperature
than actual temperature.)
4
Disconnection or contact failure
of connector (63H) on outdoor
controller board
5
Disconnection or contact failure
of 63H connection
6
Defective outdoor controller
board
7
Defective action of linear
expansion valve
8
Malfunction of fan driving
circuit
1
–
6
Check indoor unit and repair defect.
7
Check if stop valve is fully open.
8
Check piping and repair defect.
9
–
2
Check outdoor unit and repair defect.
3
Check the detected temperature of outside
temperature thermistor on LED display.
(SW2 on A-Control Service Tool: Refer
to "10-9. FUNCTION OF SWITCHES,
CONNECTORS AND JUMPERS".)
4
–
6
Turn the power off and check F5 is
displayed when the power is on again.
When F5 is displayed, refer to “Judgment
and action” for F5.
7
Check linear expansion valve.
Refer to "10-5. HOW TO CHECK THE
PARTS".
8
Replace outdoor controller board.
Cause
Check Code
U2
(1102)
High discharge temperature
(1) Abnormal if TH4 exceeds 257˚F [125˚C]
or 230˚F [110˚C] continuously for 5
minutes.
Abnormal if TH4 exceeds 230˚F [110˚C]
or more continuously for 30 seconds
after 90 seconds have passed since the
defrosting operation started.
(2) Abnormal if discharge superheat
(Cooling: TH4−T
63HS
/ Heating: TH4−T
63HS
)
exceeds 126˚F [70˚C] continuously for
10 minutes.
TH4: Thermistor <Discharge>
High comp. surface temperature
Abnormal if TH33 exceeds 257˚F
[125˚C].
In the case of high comp. surface
temperature error, compressor does
not restart unless the thermistor (TH33)
becomes less than 203˚F [95˚C].
TH33: Thermistor <Comp. surface>
1
Overheated compressor
operation caused by shortage
of refrigerant
2
Defective operation of stop
valve
3
Defective thermistor
4
Defective outdoor controller
board
5
Defective action of linear
expansion valve
6
Clogging with foreign objects in
refrigerant circuit
Note: Clogging occur in the
parts which become below
freezing point when water
enters in refrigerant circuit.
7
In the case of the unit does not
restart:
Detection temp. of thermistor
(TH33)
]
203˚F [95˚C]
1
Check intake superheat.
Check leakage of refrigerant.
Charge additional refrigerant.
2
Check if stop valve is fully open.
34
Turn the power off and check if U3 is
displayed when the power is turned on again.
When U3 is displayed, refer to “Judgement
and action” for U3.
5
Check linear expansion valve.
Refer to "10-5. HOW TO CHECK THE
PARTS".
6
After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
