Mitsubishi Electric MXZ-2D33VA-E1 Service Manual page 80

• When the indoor unit does not operate, it cannot be operated either with the remote controller or with the
EMERGENCY OPERATION switch.
• When the outdoor unit does not operate, the OPERATION INDICATOR lamp on the indoor unit flashes ON and OFF
every 0.5-second.
How to check miswiring and serial signal error (when outdoor unit does not work)
LED indication for communication status
Communication status is indicated by the LED.
Unit status
Blinking: normal communication
Lighted: abnormal communication or not connected
Not lighted: The outdoor P.C. board is abnormal.
NOTE: "Lighted" and "Not lighted" in the table below
does not indicate abnormal.
MXZ-2D33/2D40/2D53VA/2D53VAH
Outdoor display P.C. board
LED1 LED2
LED 1 LED 2
Unit A Unit B
status status
MXZ-3D54/3D68/4D72VA
Outdoor control P.C. board
LED3 LED2 LED1
Blinking
Pattern
LED 3 LED 2
Unit B
1 Lighted
status
Unit D
2
Not lighted
status
MXZ-4D83/5D102VA
Outdoor control P.C. board
LED1 LED2 LED3
Blinking
Pattern LED 1 LED 2
Unit B
Unit A
1
status
status
Unit D
Unit E
2
status status
OBH626B
Turn ON the breaker.
Is there rated voltage
between outdoor
terminal block S1 and S2 ?
Press the EMERGENCY
OPERATION switch
once.
Does the OPERATION
INDICATOR lamp light
up? <Confirmation of
the power to the indoor
unit>
Is serial signal error
indicated 6 minutes
later?
Is there any miswiring,
poor contact, or wire
LED 1 disconnection of the
indoor/outdoor
Unit A
status
connecting wire?
Unit C
status
Turn OFF the breaker.
Remove the
indoor/outdoor connecting
wire from the outdoor
terminal block connected
LED 3
with the indoor unit on
Unit C
which miswiring or the
status
serial signal error is
Not lighted
indicated. Short-circuit
between S2 and S3 of the
outdoor terminal block .
Turn ON the breaker.
Does the LED on the
outdoor display P.C.
board or the outdoor control
P.C. board repeat quick
BLINKING and OFF? *2
Replace the inverter P.C.
board or the outdoor control
P.C. board. *3 *4
No Check the power supply
and correct the problem.
Y s e
Replace the indoor
electronic control
P.C. board. *1
Is there rated
voltage between
N o
outdoor terminal
block S1 and S2?
Yes
N o
Y s e
Check the indoor/outdoor
Y s e
connecting wire and
correct the problem.
No
*2 The LED indicates the status of serial
communication.
Check the communication status.
Replace the indoor
Yes
electronic control
P.C. board. *1 *4
No (Lighted or
not lighted)
*1 Turn OFF the breaker before replacing the indoor electronic control
P.C. board.
Refer to indoor unit service manual.
*3 Turn OFF the breaker before replacing the inverter P.C. board.
Be careful of residual voltage of smoothing capacitor.
*4 Remove the short-circuit between outdoor terminal block
S2 and S3. Connect the indoor/outdoor connecting wire.
80
*1 Turn OFF the breaker before
replacing the indoor electronic control
P.C. board.
Refer to indoor unit service manual.
Check the indoor/outdoor
N o
connecting wire and
correct the problem.
A
If the trouble sometimes occurs,
possible causes are as follows:
• Poor connection of the indoor/
A
outdoor connecting wire
Check for intermediate connection of
the indoor/outdoor connecting wire,
loose connection to the terminal block,
and cut wire inside the cable.
If any of them is found, correct the
problem(s).
• Effects of the inverter lighting
on the indoor unit
If the trouble occurs or does not occur
depending on whether the light is on
or off, distance the lighting from the
indoor unit or apply the glass filter on
the receiving part of the indoor unit.
• Noise on the indoor/outdoor
connecting wire
Pass the indoor/outdoor connecting
wire through a different route if the
existing wiring is arranged as below:
• The indoor/outdoor connecting wire
runs near the power supply cable of
other equipment.
• The indoor/outdoor connecting wire
is detoured and run long.