UL
(1300)
Low pressure
Abnormal if the following conditions are
detected for continuously 3 minutes after
compressor starts heating operating for 10
minutes.
1. Heating mode
• Detection mode 1
TH7−TH3
[
4°C and
T
63HS
−Indoor room temperature
[
2°C
• Detection mode 2
TH7−TH3
[
2°C,
T
63HS
−Indoor room temperature
[
4°C and
TH2−Indoor room temperature
[
4°C
2. Cooling mode
TH6−TH7
[
2°C and
TH3−TH7
[
2°C and
Indoor room temperature−Indoor liquid
pipe temperature (TH2)
[
5°C
Thermistor TH3: Outdoor liquid pipe temperature
TH6:
Outdoor 2-phase pipe temperature
TH7: Ambient temperature
T
63
HS
:
Condensing temperature
1
Stop valve of outdoor unit is
closed during operation.
2
Leakage or shortage of
refrigerant
3
Malfunction of linear expansion
valve
4
Clogging with foreign objects in
refrigerant circuit
Note: Clogging occurs in the
parts which become below
freezing point when water
enters in refrigerant circuit.
1
Check stop valve.
2
Check intake superheat.
Check leakage of refrigerant.
Check additional refrigerant.
3
Check linear expansion valve.
Refer to "10-4. HOW TO CHECK THE
PARTS".
4
After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
23
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
6
DIP switch setting difference of
outdoor controller circuit board.
1
Open stop valve.
2
Check facility of power supply.
3
Correct the wiring (U
•
V
•
W phase) to
compressor. Refer to "10-6. TEST POINT
DIAGRAM" (Outdoor power circuit board).
4
Check compressor.
Refer to "10-4. HOW TO CHECK THE PARTS".
5
Replace outdoor power circuit board.
6
Check the dip switch setting of outdoor con
-
troller circuit board. Refer to "Model Select" in
"1) Function of switches" in "10-7. FUNCTION
OF SWITCHES, CONNECTORS AND
JUMPERS".
Ud
(1504)
Over heat protection
Abnormal if thermistor <liquid> (TH3)
detects 70
:
or more during compressor
operation.
1
Defective outdoor fan (fan
motor) or short cycle of outdoor
unit during cooling operation
2
Defective thermistor <liquid>
(TH3)
3
Defective outdoor controller
board
1
Check outdoor unit air passage.
23
Turn the power off and on again to check
the check code. If U4 is displayed, follow the
U4 processing direction.
Check Code Abnormal point and detection method
Case
Judgment and action
UH
(5300)
Current sensor error or input current error
• Abnormal if current sensor detects −1.0A
to 1.0A during compressor operation.
(This error is ignored in case of test run
mode.)
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 "10-6. TEST POINT
DIAGRAM" (Outdoor power circuit board).
2
Replace outdoor power circuit board.
3
Check the facility of power supply.
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
failure of connector (63HS) on
the outdoor controller circuit
board
2
Defective pressure sensor
3
Defective outdoor controller
circuit board
1
Check connection of connector (63HS) on
the outdoor controller circuit board.
Check breaking of the lead wire for thermistor
(63HS).
2
Check pressure by microprocessor.
(Pressure sensor/ 63HS)
(SW2: Refer to "10-7. FUNCTION OF
SWITCHES, CONNECTORS AND JUMPERS". )
3
Replace outdoor controller board.
OCH583
