31
OCH751
Checkcode 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 "10-9. FUNCTION OF SWITCHES, CONNECTORS AND JUMPERS".
01
Overvoltage error
• Increase in DC bus voltage to
400 V
1
Abnormal increase in power source
voltage
2
Disconnection of compressor wiring
3
Defective outdoor controller 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 "10-8. TEST
POINT DIAGRAM". (Outdoor controller
circuit board).
3
Replace outdoor controller circuit board.
4
Check compressor for electrical insula-
tion. Replace compressor.
02
Undervoltage error
• Instantaneous decrease in DC
bus voltage to 200 V
1
Decrease in power source voltage,
instantaneous stop.
2
Defective converter drive circuit in
outdoor controller circuit board
1
Check the field facility for the power
supply.
2
Replace outdoor controller circuit board
04
Input current sensor error
• Decrease in input current
through outdoor unit to 0.1A
only if operation frequency is
more than or equal to 40Hz
or compressor current is more
than or equal to 6A.
1
Defective ACCT (AC current trans)
2
Defective input current detection
circuit
3
Defective outdoor controller circuit
board
12
Replace outdoor controller circuit board
3
Replace outdoor controller circuit board.
08
Abnormal power synchronous
signal
• No input of power synchronous
signal to outdoor controller
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
Defective power synchronous signal
circuit in outdoor controller circuit
board
1
Check the field facility for the power
supply.
2
Check earth wiring.
3
Replace outdoor controller circuit board.
10
PFC/Q1 error (Overvoltage/
Undervoltage/Overcurrent)
• Increase of DC bus voltage to
400 V
• Decrease in PFC control
voltage to 12 VDC or lower
• Increase in input current to
50A peak
1
Abnormal increase in power source
voltage
2
Decrease in power source voltage,
instantaneous stop
3
Disconnection of compressor wiring
4
Misconnection of reactor (ACL)
5
Defective outdoor controller circuit
board
6
Defective reactor (ACL)
12
Check the field facility for the power
supply.
3
Correct the wiring (U.V.W phase)
to compressor. Refer to "10-8. TEST
POINT DIAGRAM". (Outdoor controller
circuit board).
4
Correct the wiring of reactor (ACL).
5
Replace outdoor controller circuit board.
6
Replace reactor (ACL).
20
IGBT error
(Undervoltage)
1
Incorrect switch settings on the
outdoor controller circuit board for
model select
2
Defective outdoor controller circuit
board
1
Correction of a model select
2
Replace outdoor controller circuit board
