Instruction Of Troubleshooting; Operation Start - Mitsubishi Electric MXZ-2B20NA Service Manual

MXZ-5B
Upper or
left lamp of
OPERATION Abnormal point
INDICATOR (Failure mode/protection)
lamp (Indoor
unit)
11-time fl ash Communication error between
P.C. boards
Current sensor
Zero cross detecting circuit
Bus-bar voltage
12-time fl ash Compressor (open phase)
14-time fl ash Power module
15-time fl ash 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 with referring to the indoor unit service manual, and confirm that there is any problem in the indoor
unit.
Then, check the outdoor unit with referring to this page.

Operation start

Check the outdoor unit
LED indicator.
Both LED1 and
LED2 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".
mis-wiring and
serial signal
error".
OBH560G
LED indication
(Outdoor P.C.
board)
Lighted 6 times Communication error occurs between the out-
door control P.C. board and outdoor power P.C.
board for more than 10 seconds.
The communication between boards protection
cut-out operates 2 consecutive times.
Lighted 7 times After the operation starts, a short or open
circuit is detected in the current sensor when
the compressor is not operating.
Current sensor has been short or open cir-
cuited for 120 seconds.
5 times Not Zero cross signal cannot be detected while the
lighted compressor is operating.
The protection cut-out of the zero cross detect-
ing circuit operates 3 consecutive times.
6 times Not The bus-bar voltage exceeds
lighted 400 V or falls to 300 V or below during com-
pressor operating.
10 Not Waveform of compressor current is distorted.
times lighted
7 times Not The overcurrent is detected when the frequen-
lighted cy of the compressor is 1 Hz or less.
Lighted Lighted 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
miss-piping. inverter/compressor".
Check mis-piping,
shortage of capacity.
60
Remedy
• Check the connecting wire between the
outdoor control P.C. board and outdoor
power P.C. board .
• Replace the outdoor power P.C. board.
• Check the connecting wire between
outdoor control P.C. board and outdoor
power P.C. board.
• Check the voltage of power supply.
• Replace the outdoor power P.C. board .
• Check the connection of the compres-
sor connecting wire.
• Refer to 11-6. " How to check in-
verter/compressor.
• Refer to 11-6. " How to check in-
verter/compressor.
• 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 is not
cool.
Refer to 11-6.
"How to check
inverter/
compressor".
Indoor/out-
door unit
failure mode
recall func-
tion
—
○
—
○
—
○
—
—
—
—