Mitsubishi Electric EHST20C-VM6HB Service Manual page 33

Check Code Abnormal point and detection method
PFC error (Overvoltage/
Detailed
codes
Undervoltage/Overcurrent)
• PFC detected any of the fol-
lowing
a) Increase of DC bus voltage to
420 V (SW75VHA(R3),SW·V),
400 V (SW75VHAR4)
b) Decrease in PFC control
10
voltage to 12 V DC or lower
c) Increase in input current to
50A peak
U9
(SW75V only)
PFC/IGBT error (Undervoltage)
• When Compressor is running,
DC bus voltage stays at 310V or
20
lower for consecutive 10 seconds
(SW·V only)
Overheat protection
Abnormal if liquid thermistor (TH3), con-
densing temperature T
or more during compressor operation.
Ud
Abnormal pressure of pressure sensor
(63HS)
Abnormal if pressure sensor (63HS)
detects 0.1 MPa or less.
UE
Detection is inoperative for 3 minutes after
compressor starting and 3 minutes after
and during defrosting.
Compressor overcurrent interruption
(When compressor locked)
Abnormal if overcurrent of DC bus or
compressor is detected within 30 seconds
after compressor starts operating.
UF
Current sensor error or input current error
• Abnormal if current sensor detects −1.0A
to 1.0A during compressor operation. (This
error is ignored in case of test run mode.)
UH
• Abnormal if 40A (SW100/120V, SW75VHAR4)
of input current is detected or 37A
(SW100/120V, SW75VHAR4) or more of
input current is detected for 10 seconds
continuously.
Low pressure (63L operated)
(SW100/120 only)
Abnormal if 63L is operated (under
−0.03MPa) during compressor operation.
63L: Low-pressure switch
UL
OCH533D
1 Abnormal increase in power
source voltage
2 Decrease in power source
voltage, instantaneous stop
3 Disconnection of compressor
wiring
4 Misconnection of reactor (ACL)
5 Defective outdoor power circuit
board
6 Defective reactor (ACL)
7 Disconnection or loose
connection of CN2 on the
outdoor power circuit board/
controller circuit board
1 Incorrect switch settings on the
outdoor controller circuit board
for model select
2 Defective outdoor power circuit
board
3 Defective outdoor controller circuit
board
1 Defective outdoor fan (fan
motor) or short cycle of outdoor
detects 70: unit during cooling operation
63HS
2 Defective liquid thermistor
(TH3), condensing temperature
T
63HS
3 Defective outdoor controller board
1 Disconnection or contact
failure of connector (63HS) on
the outdoor controller circuit
board
2 Defective pressure sensor
3 Defective outdoor controller
circuit board
1 Stop valve is closed.
2 Decrease of power supply
voltage
3 Looseness, disconnection or
converse of compressor wiring
connection
4 Defective compressor
5 Defective outdoor power board
1 Disconnection of compressor
wiring
2 Defective circuit of current
sensor on outdoor power circuit
board
3 Decrease of power supply
voltage
4 Leakage or shortage of
refrigerant
1 Stop valve of outdoor unit is
closed during operation.
2 Disconnection or loose
connection of connector (63L)
on outdoor controller board
3 Disconnection or loose
connection of 63L
4 Defective outdoor controller
board
5 Leakage or shortage of
refrigerant
6 Malfunction of linear expansion
valve
33
Case
12 Check the field facility for the power
supply.
3 Correct the wiring (U . V . W phase) to
compressor. Refer to "11-6. TEST POINT
DIAGRAM" (Outdoor power circuit board).
4 Correct the wiring of reactor (ACL).
5 Replace outdoor power circuit board.
6 Replace reactor (ACL).
7 Check CN2 wiring.
1 Correction of a model select
2 Replace outdoor power circuit board.
3 Replace outdoor controller circuit board.
1 Check outdoor unit air passage.
23 Turn the power off and on again to check
the check code. If U4 is displayed, follow
the U4 processing direction.
1 Check connection of connector (63HS) on
the outdoor controller circuit board.
Check breaking of the lead wire for
thermistor (63HS).
2 Check pressure by microprocessor.
(Pressure sensor/ 63HS)
(SW2: Refer to "11-7. FUNCTION OF
SWITCHES, CONNECTORS AND JUMPERS". )
3 Replace outdoor controller board.
1 Open stop valve.
2 Check facility of power supply.
3 Correct the wiring (U
compressor.
Refer to "11-6. TEST POINT DIAGRAM".
(Outdoor power circuit board).
4 Check compressor.
Refer to "11-4. HOW TO CHECK THE PARTS".
5 Replace outdoor power circuit board.
1 Correct the wiring (U
compressor. Refer to "11-6. TEST POINT
DIAGRAM" (Outdoor power circuit board).
2 Replace outdoor power circuit board.
3 Check the facility of power supply.
4 Check leakage of refrigerant.
1 Check stop valve.
2–4 Turn the power off and on again to check
if F3 is displayed on restarting.
If F3 is displayed, follow the F3 processing
direction.
5 Correct to proper amount of refrigerant.
6 Check linear expansion valve.
Refer to "11-4. HOW TO CHECK THE PARTS".
Judgment and action
V W phase) to
• •
V W phase) to
• •