Mitsubishi Electric MSZ-LN-VG Series Service Manual page 101

MXZ-3F, 4F
The left lamp of
OPERATION IN- Abnormal point
DICATOR lamp (Failure mode/protection)
(Indoor unit)
OFF None (Normal)
2-time blink Outdoor power system
3-time blink 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 blink Overcurrent
5-time blink Discharge temperature
6-time blink High pressure
7-time blink Fin temperature
P.C. board temperature
8-time blink Outdoor fan motor
9-time blink Outdoor control system
10-time blink Low discharge temperature
protection
11-time blink Communication error
between P.C. boards
Current sensor
Zero cross detecting circuit
Converter
Bus-bar voltage
14-time blink Refrigerant leakage
(Sensor detection)
OBH790D
LED indication
(Outdoor P.C.
board)
LED1 LED2
Lit Lit
Lit Lit 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.
Lit Once A thermistor shorts or opens during
compressor running.
Lit Once
Lit Twice
Lit 3 times
Lit 4 times
Lit 9 times
Once Not lit 21 A current flows into power module.
Lit Lit The discharge temperature exceeds 115°C
during operation.
Compressor can restart if discharge tempera-
ture thermistor reads 80°C or less 3 minutes
later.
Lit Lit The outdoor heat exchanger temperature ex-
ceeds 70°C during cooling or the indoor gas pipe
temperature exceeds 70°C during heating.
3 times Not lit The fin temperature exceeds 88°C during op-
eration.
4 times Not lit The P.C. board temperature exceeds 67°C
during operation.
Lit Lit A failure occurs 3 consecutive times within 30
seconds after the fan gets started.
Lit 5 times Nonvolatile memory data cannot be read prop-
erly.
Lit Lit 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.
Lit 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.
Lit 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 lit Zero cross signal cannot be detected while the
compressor is operating.
The protection cut-out of the zero cross
detecting circuit operates 10 consecutive
times.
5 times Not lit A failure is detected in the operation of the
converter during operation.
5 times Not lit The bus-bar voltage exceeds 400 V or falls to
low level during compressor operating.
Lit Lit 1.Refrigerant leaks from the piping or the
heat exchanger in the indoor unit.
2.The following items are used around the
indoor unit.
• Spray (LP gas including Freon, and
whose main ingredient is propane and
butane)
• Aerosol insecticide (including ethanol)
• Air spray painting (including dichlo-
romethane)
• Charcoal (charcoal fire)
• Chemicals (such as ethanol)
101
NOTE: Blinking patterns of this mode differ from the ones of
Troubleshooting check table (12-4.).
Condition
• Check the connection of the com-
pressor connecting wire.
• Refer to 12-6.
"How to check inverter/compres-
sor".
• Check the stop valve.
• Refer to 12-6.
thermistors".
• Replace the outdoor control P.C.
board.
• Refer to 12-6.
thermistors".
• Reconnect compressor connector.
• Refer to 12-6.
verter/compressor".
• Check the stop valve.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 12-6.
• Check refrigerant circuit and refrig-
erant amount.
• Check the stop valve.
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 12-6.
fan motor".
• Refer to 12-6.
fan motor".
• Replace the outdoor control P.C. board.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 12-6.
• 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.
• Turn off the power after the indoor
unit finishes its FAN operation.
(The FAN operation continues for 3
hours.)
• Check the indoor unit to detect the
part where refrigerant leaks.
• Repair the part where refrigerant
leaks.
• Turn on the power again.
• Replace the refrigerant sensor if
the problem is not fixed.
Indoor/
outdoor unit
Remedy
failure mode
recall function
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"Check of outdoor
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"Check of outdoor
"How to check in-
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"Check of LEV". —
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"Check of outdoor
"Check of outdoor
—
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"Check of LEV".
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