Mitsubishi Electric MXZ-2F33VF, Service Manual, Page: 64 / 94

64
MXZ-3F, 4F
The left lamp of
OPERATION IN-
DICATOR lamp
(Indoor unit)
Abnormal point
(Failure mode/protection)
LED indication
(Outdoor P.C.
board)
Condition Remedy
Indoor/
outdoor unit
failure mode
recall function
LED1 LED2
OFF None (Normal) Lighted Lighted
2-time fl ash Outdoor power system Lighted Lighted Overcurrent protection cut-out operates 3 con-
secutive times within 1 minute after the com-
pressor gets started, or converter protection
cut-out or bus-bar voltage protection cut-out
operates 3 consecutive times within 3 minutes
after startup.
• Check the connection of the com-
pressor connecting wire.
• Refer to 12-6.
"How to check inverter/compres-
sor".
• Check the stop valve.
○
3-time fl ash Discharge temperature thermistor Lighted Once A thermistor shorts or opens during
compressor running. • Refer to 12-6. "Check of outdoor
thermistors".
○
Defrost thermistor Lighted Once
Ambient temperature thermistor Lighted Twice
Fin temperature thermistor Lighted 3 times
P.C. board temperature thermis-
tor Lighted 4 times • Replace the outdoor control P.C.
board.
Outdoor heat exchanger tem-
perature thermistor Lighted 9 times • Refer to 12-6. "Check of outdoor
thermistors".
4-time fl ash Overcurrent Once Not
lighted
21 A current fl ows into power module. • Reconnect compressor connector.
• Refer to 12-6. "How to check in-
verter/compressor".
• Check the stop valve.
—
5-time fl ash Discharge temperature Lighted Lighted The discharge temperature exceeds 115°C
during operation.
Compressor can restart if discharge tempera-
ture thermistor reads 80°C or less 3 minutes
later.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 12-6. "Check of LEV". —
6-time fl ash High pressure Lighted Lighted The outdoor heat exchanger temperature ex-
ceeds 70°C during cooling or the indoor gas pipe
temperature exceeds 70°C during heating.
• Check refrigerant circuit and refrig-
erant amount.
• Check the stop valve.
—
7-time fl ash Fin temperature 3 times Not
lighted
The fi n temperature exceeds 88°C during op-
eration.
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 12-6. "Check of outdoor
fan motor".
—
P.C. board temperature 4 times Not
lighted
The P.C. board temperature exceeds 67°C
during operation.
8-time fl ash Outdoor fan motor Lighted Lighted A failure occurs 3 consecutive times within 30
seconds after the fan gets started.
• Refer to 12-6. "Check of outdoor
fan motor".
—
9-time fl ash Outdoor control system Lighted 5 times Nonvolatile memory data cannot be read prop-
erly.
• Replace the outdoor control P.C. board.
○
10-time fl ash Low discharge temperature
protection Lighted Lighted The frequency of the compressor is kept 80 Hz
or more and the discharge temperature is kept
under 39°C for more than 20 minutes.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 12-6. "Check of LEV".
—
11-time fl ash Communication error
between P.C. boards 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.
• Check the connecting wire between
outdoor control P.C. board and out-
door power P.C. board.
—
The communication between boards protec-
tion cut-out operates 2 consecutive times.
○
Current sensor Lighted 7 times A short or open circuit is detected in the cur-
rent sensor during compressor operating.
—
—
Current sensor protection cut-out operates 2
consecutive times.
○
Zero cross detecting circuit 5 times Not
lighted
Zero cross signal cannot be detected while the
compressor is operating. • Check the connecting wire among
outdoor control P.C. board and out-
door power P.C. board.
—
The protection cut-out of the zero cross
detecting circuit operates 10 consecutive
times.
○
Converter 5 times Not
lighted
A failure is detected in the operation of the
converter during operation. • Check the voltage of power supply.
• Replace the outdoor power P.C.
board.
—
Bus-bar voltage 5 times Not
lighted
The bus-bar voltage exceeds 400 V or falls to
low level during compressor operating. • Check the voltage of power supply.
• Replace the outdoor control P.C.
board.
15-time fl ash LEV and drain pump Lighted Lighted The indoor unit detects an abnormality in
the LEV and drain pump.
• Refer to 12-6. "Check of LEV".
• Check the drain pump of the indoor
unit.
—
NOTE : Blinking patterns of this mode differ from the ones of
Troubleshooting check table (12-4.).
OBH790