Mitsubishi Electric MXZ-3C24NA Service Manual page 61

3. Outdoor unit failure mode table
The left lamp of
OPERATION IN- Abnormal point
DICATOR lamp (Failure mode/protection)
(Indoor unit)
OFF None (Normal)
2-time fl ash Outdoor power system
3-time fl ash Discharge temperature thermistor
Defrost thermistor
Ambient temperature thermistor
Fin temperature thermistor
P.C. board temperature thermis-
tor
Outdoor heat exchanger tem-
perature thermistor
4-time fl ash Overcurrent
5-time fl ash Discharge temperature
6-time fl ash High pressure
7-time fl ash Fin temperature
P.C. board temperature
8-time fl ash Outdoor fan motor
9-time fl ash Outdoor control system
10-time fl ash Low discharge temperature
protection
11-time fl ash Communication error
between P.C. boards
Current sensor
Zero cross detecting circuit
Converter
Bus-bar voltage
15-time fl ash LEV and drain pump
NOTE: Blinking patterns of this mode differ from the ones of Troubleshooting check table (11-4.).
OBH702A
LED indication
(Outdoor P.C.
board)
LED 1 LED 2
Lighted Lighted
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 start-up.
Lighted Once A thermistor shorts or opens during
compressor running.
Lighted Once
Lighted Twice
Lighted 3 times
Lighted 4 times
Lighted 9 times
Once Not 21 A (MXZ-3C24/3C30/4C36NA)/28 A (MXZ-
lighted 5C42NA,2C20/3C24/3C30NAHZ) current
fl ows into power module.
Lighted Lighted The discharge temperature exceeds 240.8 °F
during operation.
Compressor can restart if discharge tempera-
ture thermistor reads 212 °F or less 3 minutes
later.
Lighted Lighted The outdoor heat exchanger temperature ex-
ceeds 158°F during cooling or the indoor gas
pipe temperature exceeds 158 °F during heating.
3 times Not The fin temperature exceeds 192 °F during
lighted operation.
The P.C. board temperature exceeds 189 °F
4 times Not
lighted during operation.
Lighted Lighted A failure occurs 3 consecutive times within 30
seconds after the fan gets started.
Lighted 5 times Nonvolatile memory data cannot be read prop-
erly.
Lighted Lighted The frequency of the compressor is kept 80 Hz
or more and the discharge temperature is kept
under 102.2 °F for more than 20 minutes.
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 protec-
tion cut-out operates 2 consecutive times.
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.
5 times Not Zero cross signal cannot be detected while the
lighted compressor is operating.
The protection cut-out of the zero cross
detecting circuit operates 10 consecutive
times.
5 times Not A failure is detected in the operation of the
lighted converter during operation.
6 times Not The bus-bar voltage exceeds 400 V or falls to
lighted low level during compressor operating.
Lighted Lighted The indoor unit detects an abnormality in
the LEV and drain pump.
61
Condition
• Check the connection of the com-
pressor connecting wire.
• Refer to 11-6.
"How to check inverter/compres-
sor".
• Check the stop valve.
• Refer to 11-6.
thermistors".
• Replace the outdoor control P.C.
board.
• Refer to 11-6.
thermistors".
• Reconnect compressor connector.
• Refer to 11-6.
verter/compressor".
• Check the stop valve.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 11-6.
• Check refrigerant circuit and refrig-
erant amount.
• Check the stop valve.
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 11-6.
fan motor".
• Refer to 11-6.
fan motor".
• Replace the outdoor control P.C. board.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 11-6.
• Check the connecting wire between
outdoor control P.C. board and out-
door power P.C. board.
• Check the connecting wire among
outdoor control P.C. board and out-
door power P.C. board.
• Check the voltage of power supply.
• Replace the outdoor power P.C.
board.
• Check the voltage of power supply.
• Replace the outdoor control P.C.
board.
• Refer to 11-6.
• Check the drain pump of the indoor
unit.
Indoor/
outdoor unit
Remedy
failure mode
recall function
○
"Check of outdoor
○
"Check of outdoor
"How to check in-
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"Check of LEV". —
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"Check of outdoor
"Check of outdoor
—
○
—
"Check of LEV".
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○
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○
—
○
—
"Check of LEV".
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