42
Check Code Abnormal points and detection method
Case
Judgment and action
Ud
(UD)*
(1504)
Over heat protection
Abnormal if outdoor pipe thermistor (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 outdoor pipe thermistor
(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.
* The check code in the parenthesis indi-
cates PAR−3xMAA ("x" represents 0 or
later).
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 con-
verse of compressor wiring connec-
tion
4
Defective compressor
5
Defective outdoor power board
6
DIP switch setting difference of out-
door 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 "10-9. TEST POINT DIAGRAM".
(Outdoor power circuit board).
4
Check compressor.
Refer to "10-6. 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 Refer to "10-10. FUNCTION
OF SWITCHES, CONNECTORS AND
JUMPERS".
UH
(5300)
Current sensor error
Abnormal if current sensor detects −1.0 A
to 1.0 A 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
1
Correct the wiring (U
•
V
•
W phase) to
compressor. Refer to "10-9. TEST
POINT DIAGRAM". (Outdoor power
circuit board).
2
Replace outdoor power circuit board.
UL
(1300)
Low pressure
Abnormal if the following conditions are
detected for continuously 3 minutes after
compressor starts heating operating for 10
minutes.
1. TH7−TH3
[
4°C and
TH5−Indoor room temperature
[
2°C
Detection mode 2
Thermistor TH3: Outdoor liquid pipe temperature
TH5: Indoor cond./eva. temperature
TH7: Ambient 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:
If water enters in refrigerant circuit,
clogging may occur where the part
becomes below freezing point.
1
Check stop valve.
2
Check intake superheat.
Check leakage of refrigerant.
Check additional refrigerant.
3
Check linear expansion valve.
Refer to "10-6. HOW TO CHECK THE
PARTS".
4
After recovering refrigerant, remove
water from entire refrigerant circuit under
vacuum more than 1 hour.
OCH653
