Mitsubishi Electric MXZ-2B30VA Service Manual page 69

Upper or left lamp of
Abnormal point
OPERATION INDICATOR
(Failure mode / protection)
lamp (Indoor unit)
Communication error
11-time flash
between P.C. boards
Current sensor
Zero cross detecting circuit
Converter
Bus-bar voltage
(1)
Bus-bar voltage
(2)
Even if this protection stop is
performed continuously three
times, it does not mean the
abnormality in outdoor power
system.
15-time flash LEV and drain pump
NOTE: Blinking patterns of this mode differ from the ones of "Troubleshooting check table" (11-4).
11-3. INSTRUCTION OF TROUBLESHOOTING
• Check the indoor unit by referring to the indoor unit service manual, and confirm whether there is any problem in the indoor
unit.
Then, check the outdoor unit by referring to this page.
Operation start
Check the outdoor unit
LED indicator.
Both LED 1
and LED 2
are OFF.
Refer to 11-6.
"Check of power supply".
• Indoor unit • COOL or
serial signal HEAT
error operation only
Refer to 11-6. Refer to 11-6.
"How to "Check of
check R.V. coil".
miswiring and
serial signal
error".
OBH554D
LED indication
(Outdoor P.C. board)
LED 1 LED 2
Communication error occurs
Lighting 6 times
between the electronic control P.C.
board and power board for more
than 10 seconds.
The communication between
boards protection cut-out operates
2 consecutive times.
Lighting 7 times A short or open circuit is detected in
the current sensor during compressor
operating.
Current sensor protection cut-out
operates 2 consecutive times.
5 times Goes
Zero cross signal cannot be detected
out
while the compressor is operating.
The protection cut-out of the zero
cross detecting operates 10
consecutive times.
5 times Goes
A failure is detected in the operation
out of the converter during operation.
5 times
Goes
The bus-bar voltage exceeds 400 V or
out
falls to 200 V or below during
compressor operating.
6 times
Goes
The bus-bar voltage exceeds
out
400 V (MXZ-3B54/3B68/4B71VA)
430 V (MXZ-4B80/5B100VA)
or falls to 50V or below during
compressor operating.
Lighting Lighting
The indoor unit detects an abnormality
in the LEV and drain pump.
Both LED 1 and
LED 2 are lighting.
• When cooling, heat
exchanger of
non-operating indoor
unit frosts.
•When heating, non-
operating indoor unit
gets warm.
Refer to 11-6.
"Check of LEV".
Condition
• When cooling, • When heating,
dew drops in the room does not get
non-operating warm.
indoor unit. Refer to 11-6.
Check of "How to check of
mispiping inverter/compressor".
Check mispiping,
shortage of capacity
69
Indoor/outdoor
Remedy
unit failure mode
recall function
• Check the connecting
wire between outdoor
electronic control
P.C. board and power
board.
• Replace the power
board.
• Check the connecting
wire among electronic
control P.C. board,
noise filter P.C. board
and power board.
• Check the voltage of
power supply.
• Replace the power board.
• Check the voltage of
power supply.
• Replace the outdoor
electronic control
P.C. board.
• Refer to 11-6. "Check
of LEV".
• Check the drain pump of
the indoor unit.
LED 1 or LED 2
has blinked.
Refer to 11-4.
"Troubleshooting check table".
• When cooling,
room does not
cool.
Refer to 11-6.
"How to check
of inverter/
compressor".