Mitsubishi Electric PUHZ-W50VHA-BS Service Manual page 48

Abnormal point and detection method
Error Code
Overvoltage or voltage shortage and
synchronous signal to main circuit
Abnormal if any of followings are detected
during compressor operation;
• Decrease of DC bus voltage to 310V
(50-140V only)
• Instantaneous decrease of DC bus voltage
50-140V : 200V
112,140Y : 350V
• Increase of DC bus voltage to
50V : 420V
85-140V : 400V
112,140Y : 760V
• Decrease of input current of outdoor unit
to 0.1A only if operation frequency is
more than or equal to 40Hz or compres-
sor current is more than or equal to 6A.
* Check U9 error detail (SW2 all ON)
Refer to 9-7.
U9
Overheat protection
Abnormal if outdoor pipe thermistor (TH3)
detects 70: or more or condensing
temperature of pressure sensor (63HS)
Ud
detects 70: or more during compressor
operation.
Compressor overcurrent interruption
(When compressor locked)
Abnormal if overcurrent of DC bus or
compressor is detected within 30 seconds
after compressor starts operating.
UF
OCH439H
Case
1 Decrease of power supply
voltage
2 Disconnection of compressor
wiring
3 Defective power circuit board
4 Disconnection or loose
connection of CN52C (50-140V)
5 Defective PFC module of
outdoor power board (50V)
6 Defective ACT module (85V)
7 Defective ACT module drive
circuit of outdoor power circuit
board (85V)
8 Disconnection or loose
connection of CNAF (85V)
9 Disconnection or loose
connection of CN7 on the outdoor
power circuit board/outdoor
converter board (112, 140Y)
0 Defective outdoor converter
circuit board (112, 140Y)
1 Defective current sensor of
outdoor noise filter board (50,
85V/112, 140Y)
2 Defective 52C drive circuit of
outdoor controller circuit board
(50-140V)
3 Disconnection or loose
connection of CN5 on the
outdoor power circuit board
(50, 85V)
4 Defective 52C drive circuit of
outdoor power circuit board
(112, 140Y)
5 Disconnection or loose
connection of CN2 on the
outdoor power circuit board
1 Defective outdoor fan (fan
motor) or short cycle of outdoor
unit during cooling operation
2 Defective outdoor pipe
thermistor (TH3)
3 Defective outdoor controller
board
4 Defective pressure sensor
1 Decrease of power supply
voltage
2 Looseness, disconnection or
converse of compressor wiring
connection
3 Defective compressor
4 Defective outdoor power board
5 Decreased water flow
6 Clogged filter of water pipe
7 Clogged plate heat exchanger
8 Locked water pump
9 Malfunction of water pump
48
Judgment and action
1 Check the facility of power supply.
2 Correct the wiring (U
V W phase) to com-
• •
pressor. Refer to 9-6 (Outdoor power circuit
board).
3 Replace power circuit board.
4 Check CN52C wiring.
5 Replace outdoor power circuit board.
(50V)
6 Replace ACT module. (85V)
7 Replace outdoor power circuit board. (85V)
8 Check CNAF wiring. (85V)
9 Check CN7 wiring. (112, 140Y)
0 Replace outdoor converter circuit board.
(112, 140Y)
1 Replace outdoor noise filter circuit board.
(50, 85V/112, 140Y)
2 Replace outdoor controller circuit board.
(50-140V)
3 Check CN5 wiring on the outdoor power cir-
cuit board. (50, 85V)
Refer to 9-6.
4 Replace outdoor power circuit board.
(112, 140Y)
5 Check CN2 wiring on the outdoor power cir-
cuit board. Refer to 9-6.
1 Check outdoor unit air passage.
23 Turn the power off and on again to check
the error code. If U4 is displayed, follow the
U4 processing direction.
4 Check pressure by microcomputer.
(Pressure sensor/ 63HS)
(SW2: Refer to 9-7.)
1 Check facility of power supply.
2 Correct the wiring (U
• V • W phase) to
compressor.
Refer to 9-6 (Outdoor power circuit board).
3 Check compressor. Refer to 9-4.
4 Replace outdoor power circuit board.
5 9 Check water circuit and repair the defect.
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