Mitsubishi Electric MXZ-2B30VA, Service Manual

Page: 69 / 204

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