Abnormal points and detection method
Case
Judgment and action
Check code
40
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
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.
UH
(5300)
Compressor current sensor error or
input current error
• Abnormal if compressor current sensor
detects −1.5A to 1.5A during compressor
operation. (This error is ignored in case
of test run mode.)
• Abnormal if the input current of 38A is
detected or the input current of 34A or
more is detected for 10 seconds.
(VHA)
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 3 minutes continuously after
compressor starts heating operation for 10
minutes.
(However, this abnormal detection is
disregarded when the compressor driving
time exceeds 30 minutes after power is on.)
TH7-TH3
[
4
:
TH5-Indoor room temperature
[
2
:
Thermistor TH3:Liquid pipe temperature
TH5:Indoor cond./eva. Temperature
TH7:Ambient temperature
Note:
In the case of UL error, the compressor
may be damaged if the unit is restarted by
remote controller. To avoid the damage,
unit has the system that is not able to be
restarted unless the power is turned OFF
once .
1
Stop valve of outdoor unit is
closed during operation.
2
Leakage or shortage of
refrigerant
3
Malfunction of linear expansion
valve
1
Check stop valve.
2
Check intake super heat.
Check leakage of refrigerant.
Charge additional refrigerant.
3
Check linear expansion valve.
Refer to "10-6. HOW TO CHECK THE
PARTS".
Ud
(1504)
Overheat protection
Abnormal if liquid 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 liquid 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.
10
PFC error (Overvoltage/
Undervoltage/Overcurrent)
• PFC detected any of the fol
-
lowings
a) Increase in DC bus voltage
to 420V
b) Decrease in PFC control
voltage to 12 V DC or lower
c) Increase in input current to
50A peak
(For models equipped with
single-phase PFC only)
Not applicable for SP100, 125,
140VHA and SP100, 125,
140YHA models.
Check for the switch settings for Model Select
on the outdoor controller circuit board.
20
ACTM/IGBT error
(Undervoltage)
• When Compressor is running,
DC bus voltage stays at 310V
or lower for consecutive 10
seconds.
(VHA models only)
1
Incorrect switch settings on the
outdoor controller circuit board
for model select
2
Defective outdoor power circuit
board
3
Defective outdoor controller
circuit board
1
Correction of a model select
2
Replace outdoor power circuit board.
3
Replace outdoor controller circuit board.
U9
(4220)
Detailed
codes
From the previous page.
OCH566A
