Mitsubishi Electric PUZ-A12NKA7 Service Manual page 35

Check code Abnormal points and detection method
To find out the detail history (latest) about U9 error, turn ON SW2-1, 2-2, and 2-6.
Detailed
Refer to "10-10. FUNCTION OF SWITCHES, CONNECTORS AND JUMPERS".
codes
Overvoltage error
• Increase in DC bus voltage to:
A12, 18N: 400 V
A24, 30, 36, 42N: 430 V
01
Undervoltage error
• Instantaneous decrease in DC
bus voltage to 200 V
02
Input current sensor 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
04
than or equal to 6 A.
U9
(4220)
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
08 more is detected on power
circuit board.
PFC error (Overvoltage/
Undervoltage/Overcurrent)
• PFC detected any of the fol-
lowing:
a) Increase of DC bus voltage
as follows:
A12, 18N: 400 V
A24, 30, 36, 42N: 430 V
10
b) Decrease in PFC control
voltage to 13 V DC or lower
(A24–42N only)
c) Increase in input current as
follows:
A12, 18N: 50 A peak
A24, 30N: 42 A peak
A36, 42N: 62 A peak
OCH636A
Case
1 Abnormal increase in power
source voltage
2 D isconnection of compressor
wiring
3 D efective outdoor power circuit
board
4 C ompressor has a ground fault.
1 D ecrease in power source
voltage, instantaneous stop.
2 Defective converter drive circuit
in outdoor power circuit board
3 Defective 52C drive circuit in
outdoor power circuit board
4 Disconnection or loose
connection of CN2 on the
outdoor power circuit board/
controller circuit board
5 Power circuit failure on DC
supply for 15 V DC output on
outdoor controller circuit board
1 Defective input current
detection circuit in outdoor
power circuit board
2 Defective outdoor controller
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 in outdoor controller
circuit board
5 Defective power synchronous
signal circuit in outdoor power
circuit board
1 Abnormal increase in power
source voltage
2 Decrease in power source
voltage, instantaneous stop
3 Disconnection of compressor
wiring
4 Misconnection of reactor (DCL)
5 Defective outdoor power circuit
board
6 Defective reactor (DCL)
7 Disconnection or loose
connection of CN2 on the
outdoor power circuit board/
controller circuit board
35
judgment and action
1 C heck the field facility for the power supply.
2 C orrect the wiring (U . V . W phase) to
compressor. Refer to "10-9. TEST POINT
DIAGRAM" (Outdoor power circuit board).
3 R eplace outdoor power circuit board.
4 C heck compressor for electrical insulation.
Replace compressor.
1 C heck the field facility for the power supply.
2 Replace outdoor power circuit board.
3 Replace outdoor power circuit board.
4 C heck CN2 wiring.
5 R eplace outdoor controller circuit board.
1 Replace outdoor power circuit board.
2 Replace outdoor controller circuit board.
1 Check the field facility for the power supply.
2 Check earth wiring.
3 Check CN2 wiring. (A24–42N only)
4 Replace outdoor controller circuit board.
5 Replace outdoor power circuit board.
(A24–42N only)
12 C heck the field facility for the power supply.
3 Correct the wiring (U·V·W phase) to
compressor. Refer to "10-9. TEST POINT
DIAGRAM".
4 Correct the wiring (U·V·W phase) or reactor
(DCL). (A24–42N only)
5 Replace outdoor power circuit board.
6 Replace reactor (DCL). (A24–42N only)
7 Check CN2 wiring. (A24–42N only)