Mitsubishi Electric PUZ-SM100VKA2 Service Manual page 33

Abnormal point and detection method
Check code
To find out the detail history (latest) about U9 error, turn ON SW2-1, 2-2 and 2-6.
Detailed
Refer to "9-9. FUNCTION OF SWITCHES, CONNECTORS AND JUMPERS".
codes
Overvoltage error
• Increase in DC bus voltage to
PUZ-SM·VKA2: 430 V
01
PUZ-SM·YKA2: 760 V
Undervoltage error
• Instantaneous decrease in DC
bus voltage to
PUZ-SM·VKA2: 200 V
PUZ-SM·YKA2: 350 V
02
U9
(4220)
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.
04
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
08
circuit board.
OCH774A
Cause
Abnormal increase in power source
voltage
Disconnection of compressor wiring
Defective outdoor power circuit
board
Compressor has a ground fault.
Decrease in power source voltage,
instantaneous stop
Defective converter drive circuit in
outdoor power circuit board (PUZ-
SM·VKA2)
Defective 52C drive circuit in outdoor
power circuit board
Disconnection or loose connection
of rush current protect resistor RS
(PUZ-SM·YKA2)
Defective rush current protect
resistor RS (PUZ-SM·YKA2)
Disconnection or loose connection
of CN2 on the outdoor power circuit
board /controller circuit board (PUZ-
SM·VKA2)
Power circuit failure on DC supply for
15 V DC output on outdoor controller
circuit board (PUZ-SM·VKA2)
L1-phase open (PUZ-SM·YKA2)
Disconnection or loose connection
between TB1 and outdoor noise filter
circuit board (PUZ-SM·YKA2)
Disconnection or loose connection
of CN5 on the outdoor power circuit
board/CNCT on the outdoor noise
filter board (PUZ-SM·YKA2)
Defective ACCT (AC current trans)
on the outdoor noise filter circuit
board (PUZ-SM·YKA2)
Defective input current detection
circuit in outdoor power circuit board
Defective outdoor controller circuit
board
Distortion of power source voltage,
noise superimposition
Disconnection or loose connection of
earth wiring
Disconnection or loose connection
of CN2 on the outdoor power circuit
board /controller circuit board
Defective power synchronous signal
circuit in outdoor controller circuit
board
Defective power synchronous signal
circuit in outdoor power circuit board
33
Judgment and action
Check the field facility for the power
supply.
Correct the wiring (U . V . W phase) to
compressor. Refer to "9-8. TEST POINT
DIAGRAM (Outdoor power circuit board)".
Replace outdoor power circuit board.
Check compressor for electrical insula-
tion. Replace compressor.
Check the field facility for the power
supply.
Replace outdoor power circuit board.
(PUZ-SM·VKA2)
Replace outdoor power circuit board.
Check RS wiring. (PUZ-SM·YKA2)
Replace RS. (PUZ-SM·YKA2)
Check CN2 wiring. (PUZ-SM·VKA2)
Replace outdoor controller circuit board.
(PUZ-SM·VKA2)
Check the field facility for the power
supply. (PUZ-SM·YKA2)
Check the wiring between TB1 and
outdoor noise filter circuit board. (PUZ-
SM·YKA2)
Check CN5/CNCT wiring. (PUZ-
SM·YKA2)
Replace outdoor noise filter circuit
board. (PUZ-SM·YKA2)
Replace outdoor power circuit board.
Replace outdoor controller circuit board.
Check the field facility for the power
supply.
Check earth wiring.
Check CN2 wiring.
Replace outdoor controller circuit board.
Replace outdoor power circuit board.
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