39
OCH737
Check Code Abnormal points and detection method
Cause
Judgment and action
U9
(4220)
Detailed
codes
To find out the detail history (latest) about U9 error, turn ON SW2-1, 2-2 and 2-6.
Refer to "10-10. FUNCTION OF SWITCHES, CONNECTORS AND JUMPERS".
01
Overvoltage error
• Increase in DC bus voltage to
M200/250Y: 760 V
1
Abnormal increase in power source
voltage
2
Disconnection of compressor wiring
3
Defective outdoor power circuit board
4
Compressor has a ground fault.
1
Check the field facility for the power
supply.
2
Correct the wiring (U.V.W phase) to
compressor. Refer to "10-9. TEST POINT
DIAGRAM" (Outdoor power circuit board).
3
Replace outdoor power circuit board.
4
Check compressor for electrical insula-
tion. Replace compressor.
02
Undervoltage error
• Instantaneous decrease in DC
bus voltage to
M200/250Y: 400 V
1
Decrease in power source voltage,
instantaneous stop.
2
Defective 52C drive circuit in outdoor
power circuit board
3
Disconnection or loose connection of
rush current protect resistor RS
4
Defective rush current protect
resistor RS
1
Check the field facility for the power
supply.
2
Replace outdoor power circuit board.
3
Check RS wiring.
4
Replace RS.
04
Input current sensor error/
L1-phase open error
• Decrease in input current
through outdoor unit to 0.1 A
only if operation frequency is
more than or equal to 40 Hz
or compressor current is more
than or equal to 6 A.
1
L1-phase open
2
Disconnection or loose connection
between TB1 and outdoor noise filter
circuit board
3
Disconnection or loose connection
of CN5 on the outdoor power circuit
board/CNCT on the outdoor noise filter
board
4
Defective ACCT (AC current trans)
on the outdoor noise filter circuit
board
5
Defective input current detection
circuit in outdoor power circuit board
6
Defective outdoor controller circuit
board
1
Check the field facility for the power supply.
2
Check the wiring between TB1 and out
door noise filter circuit board.
3
Check CN5/CNCT wiring.
4
Replace outdoor noise filter circuit board.
5
Replace outdoor power circuit board.
6
Replace outdoor controller circuit board.
08
Abnormal power synchronous
signal
• No input of power synchronous
signal to power circuit board
• Power synchronous signal
of 44 Hz or less, or 65 Hz or
more is detected on power
circuit board.
1
Distortion of power source voltage,
noise superimposition.
2
Disconnection or loose connection of
earth wiring
3
Disconnection or loose connection
of CN2 on the outdoor power circuit
board/controller circuit board
4
Defective power synchronous signal
circuit in outdoor controller circuit
board
5
Defective power synchronous signal
circuit in outdoor power circuit board
1
Check the field facility for the power supply.
2
Check earth wiring.
3
Check CN2 wiring.
4
Replace outdoor controller circuit board.
5
Replace outdoor power circuit board.
10
PFC error (Overvoltage/
Undervoltage/Overcurrent)
• PFC detected any of the fol-
lowing:
a) Increase of DC bus voltage
to 420 V.
b) Decrease in PFC control
voltage to 12 V DC or lower.
c) Increase in input current
to 50 A peak. (For models
equipped with single-phase
PFC only)
Not applicable for M200/250Y model. Check the switch setting for Model Select
on the outdoor controller circuit board.
20
PFC/IGBT error (Undervoltage)
• When Compressor is running,
DC bus voltage stays at 310V
or lower for consecutive 10
seconds
Not applicable for M200/250Y model. Check the switch setting for Model Select
on the outdoor controller circuit board.