Error Code
Abnormal point and detection method
Case
Judgment and action
28
U9
(4220)
Detailed
codes
To find out the details about U9 error, turn ON SW2-1, 2-2, 2-3, 2-4, 2-5 and 2-6 when U9 error occurs.
To find out the detail history (latest) about U9 error, turn ON SW2-1, 2-2 and 2-6.
Refer to 9-10.
01
Overvoltage error
• Increase in DC bus voltage to
SHW80, 112VHA: 400V
SHW112, 140YHA: 760V
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 9-9 (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
SHW80, 112VHA: 200V
SHW112, 140YHA: 350V
1
Decrease in power source voltage,
instantaneous stop.
2
Disconnection or loose connection
of CN52C on the outdoor power
circuit board/controller circuit board
(SHW·VHA)
3
Defective converter drive circuit
in outdoor power circuit board
(SHW·VHA)
4
Defective 52C drive circuit in outdoor
power circuit board
5
Defective outdoor converter circuit
board (SHW·YHA)
6
Disconnection or loose connection
of rush current protect resistor RS
(SHW·YHA)
7
Defective rush current protect
resistor RS (SHW·YHA)
8
Disconnection or loose connection
of main smoothing capacitor CB
(SHW·VHA)
9
Disconnection or loose connection
of CN2 on the outdoor power circuit
board /controller circuit board
(SHW·VHA)
0
Power circuit failure on DC supply
for 18V DC output on outdoor
controller circuit board (SHW·VHA)
1
Check the field facility for the power
supply.
2
Check CN52C wiring. (SHW·VHA)
3
Replace outdoor power circuit board.
(SHW·VHA)
4
Replace outdoor power circuit board.
5
Replace outdoor converter circuit
board. (SHW·YHA)
6
Check RS wiring. (SHW·YHA)
7
Replace RS. (SHW·YHA)
8
Check CB wiring. (SHW·VHA)
9
Check CN2 wiring. (SHW·VHA)
0
Replace outdoor controller circuit board.
(SHW·VHA)
04
Input current sensor error/
L1-phase open 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
L1-phase open (SHW·YHA)
2
Disconnection or loose connection
between TB1 and outdoor noise filter
circuit board (SHW·YHA)
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 (SHW·YHA)
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. (SHW·YHA)
2
Check the wiring between TB1 and
outdoor noise filter circuit board.
(SHW·YHA)
3
Check CN5/CNCT wiring. (SHW·YHA)
4
Replace outdoor noise filter circuit
board. (SHW·YHA)
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.
Continue to the next page.
OCH526