Mitsubishi Electric EHST20C-VM6HB Service Manual page 32

Check Code Abnormal point and detection method
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.
Detailed
To find out the detail history (latest) about U9 error, turn ON SW2-1, 2-2 and 2-6.
codes
Refer to "11-7. FUNCTION OF SWITCHES, CONNECTORS AND JUMPERS".
Overvoltage error
• Increase in DC bus voltage to
SW75VHA(R3): 420 V
SW75VHAR4: 400 V
01
SW100, 120V: 400 V
SW100, 120Y: 760 V
Undervoltage error
• Instantaneous decrease in DC
bus voltage to
SW75, 100, 120V: 200 V
SW100, 120Y: 350 V
02
U9
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
08
more is detected on power
circuit board.
OCH533D
Case
1 Abnormal increase in power source volt-
age
2 Disconnection of compressor wiring
3 Defective outdoor power circuit
board
4 Compressor has a ground fault.
1 Decrease in power source voltage,
instantaneous stop
2 Disconnection or loose connection of
CN52C on the outdoor power circuit
board/controller circuit board (SW100,
120V)
3 Disconnection or loose connection
of CN52C on the outdoor noise filter
circuit board/controller circuit board
(SW75VHA(R3))
4 Defective converter drive circuit in
outdoor power circuit board (SW·V)
5 Defective 52C drive circuit in outdoor
power circuit board (SW100, 120V/Y,
SW75VHAR4)
6 Defective 52C drive circuit in
outdoor noise filter circuit board
(SW75VHA(R3))
7 Defective outdoor converter circuit
board (SW·Y)
8 Disconnection or loose connection of
rush current protect resistor RS (SW·Y)
9 Defective rush current protect resis-
tor RS (SW·Y)
0 Disconnection or loose connection
of main smoothing capacitor CB
(SW100,120V)
1 Disconnection or loose connection of
CN2 on the outdoor power circuit board
/controller circuit board (SW100,120V)
2 Power circuit failure on DC supply
for 18V DC output on outdoor con-
troller circuit board (SW100,120V)
1 L1-phase open (SW·Y)
2 Disconnection or loose connection
between TB1 and outdoor noise filter
circuit board (SW75V(R3), SW·Y)
3 Disconnection or loose connection of
CN5 on the outdoor power circuit board/
CNCT on the outdoor noise filter board
(SW75V(R3), SW·Y)
4 Defective ACCT (AC current trans)
on the outdoor noise filter circuit
board (SW75V(R3), SW·Y)
5 Defective input current detection
circuit in outdoor power circuit board
6 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
circuit in outdoor controller circuit board
5 Defective power synchronous signal
circuit in outdoor power circuit board
32
Judgment and action
1 Check the field facility for the power supply.
2 Correct the wiring (U . V . W phase) to
compressor. Refer to "11-6. TEST POINT
DIAGRAM" (Outdoor power circuit board).
3 Replace outdoor power circuit board.
4 Check compressor for electrical
insulation. Replace compressor.
1 Check the field facility for the power
supply.
23 Check CN52C wiring. (SW·V exclud-
ing SW75VHAR4)
4 Replace outdoor power circuit board.
(SW·V)
5 Replace outdoor power circuit board.
(SW100,120V/Y, SW75VHAR4)
6 Replace outdoor noise filter circuit
board. (SW75VHA(R3))
7 Replace outdoor converter circuit
board. (SW·Y)
8 Check RS wiring. (SW·Y)
9 Replace RS. (SW·Y)
0 Check CB wiring. (SW100,120V)
1 Check CN2 wiring. (SW100,120V)
2 Replace outdoor controller circuit
board. (SW100,120V)
1 Check the field facility for the power
supply. (SW·Y)
2 Check the wiring between TB1 and
outdoor noise filter circuit board.
(SW75V(R3), SW·Y)
3 Check CN5/CNCT wiring. (SW75V(R3),
SW·Y)
4 Replace outdoor noise filter circuit
board. (SW·Y)
5 Replace outdoor power circuit board.
6 Replace outdoor controller 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.