Mitsubishi Electric SEZ-M-DA Series, Service Manual

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110
LED indication for communication status
Communication status is indicated by the LED.
Unit status No
Blinking: normal communication
Lighted: abnormal communication or not connected
Yes Not lighted: The outdoor P.C. board is abnormal.
NOTE: "Lighted" and "Not lighted" in the table below
does not indicate abnormal.
*1 Turn OFF the power supply before
replacing the indoor electronic control
P.C. board.
Refer to indoor unit service manual.
Outdoor display P.C. board
No No
LED 1 LED 2
Unit A Unit B
status status
Yes
No
Yes
Yes
No
Yes
No (Lit or not lit)
*1 Turn OFF the power supply before replacing the indoor electronic
control P.C. board.
Refer to indoor unit service manual.
*3 Turn OFF the power supply 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.
Turn ON the power supply.
Is there rated voltage
between outdoor
terminal block S1 and S2?
Check the power supply
and correct the problem.
Press the EMERGENCY
OPERATION switch
once.
Does the OPERATION
INDICATOR lamp light
up? <Confirmation of
the power to the indoor
unit>
Is there rated
voltage between
outdoor terminal
block S1 and S2?
Check the indoor/outdoor
connecting wire and
correct the problem.
Replace the indoor
electronic control
P.C. board. *1
Is serial signal error
indicated 6 minutes
later?
Is there any miswiring,
poor contact, or wire
disconnection of the
indoor/outdoor
connecting wire?
Check the indoor/outdoor
connecting wire and
correct the problem.
Turn OFF the power supply.
Turn ON the power supply.
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 indoor
electronic control
P.C. board. *1 *4
*2 The LED indicates the status of serial
communication.
Check the communication status.
Replace the inverter P.C.
board or the outdoor control
P.C. board. *3 *4
If the trouble sometimes occurs,
possible causes are as follows:
• Poor connection of the indoor/
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.
Remove the indoor/out-
door connecting wire from
the outdoor terminal block
connected with the indoor
unit on which miswiring or
the serial signal error is
indicated. Short-circuit
between S2 and S3 of the
outdoor terminal block.
Blinking
LED1 LED2
How to check miswiring and serial signal error (when outdoor unit does not work)
• 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 blinks ON and OFF
every 0.5-second.
MXZ-2F33VF/2F42VF/2F53VF/2F53VFH
MXZ-2F33VF2/2F42VF2/2F53VF2/2F53VFH2
MXZ-2F33VF3/2F42VF3/2F53VF3/2F53VFH3
OBH790D