Mitsubishi Electric Mr.Slim MUZ-GC25NA - C1, Service Manual

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31
MUZ-GC50NA-
C1
MUZ-GC60/71NA
No. Symptom
Indication
Abnormal point /
Condition
Condition Correspondence
LED1
(Red)
LED2
(Yellow)
1
Outdoor unit
does not op-
erate.
Lightning Twice
Outdoor power system
Overcurrent protection stop is continuously performed 3 times
within 1 minute after the compressor gets started, or when
converter protection stop or bus-bar voltage protection stop is
continuously performed 3 times within 3 minutes after start-up.
• Check the connection of the com-
pressor connecting wire.
• Refer to 9-5. "How to check in-
verter/compressor".
• Check the stop valve.
2
Lightning 3 times Discharge temperature
thermistor
A short circuit is detected in the thermistor during operation, or
when an open circuit is detected in the thermistor after 10 min-
utes of compressor start-up.
• Refer to 9-5. "Check of outdoor
thermistor".
3
Lightning 4 times Fin temperature ther-
mistor
A short or open circuit is detected in the thermistor during op-
eration.
• Refer to 9-5. "Check of outdoor
thermistor".
P.C board temperature
thermistor
• Replace the outdoor electronic
control P.C. board.
4
Lightning 5 times Ambient temperature
thermistor
A short or open circuit is detected in the thermistor during op-
eration.
• Refer to 9-5. "Check of outdoor
thermistor".
Outdoor heat exchanger
temperature thermistor
A short circuit is detected in the thermistor during operation, or
an open circuit is detected in the thermistor after 5 minutes (in
cooling) and 10 minutes (in heating) of compressor start-up.
Defrost thermistor
A short circuit is detected in the thermistor during operation, or
an open circuit is detected in the thermistor after 5 minutes of
compressor start-up.
5
Lightning 6 times Serial signal The communication fails between the indoor and outdoor unit
for 3 minutes.
• Refer to 9-5. "How to check mis-
wiring and serial signal error.
6
Lightning 7 times Nonvolatile memory
data
The nonvolatile memory data cannot be read properly.
• Replace the outdoor electronic
control P.C. board.
7
Lightning 8 times Current sensor
Current sensor protection stop is continuously performed twice. • Replace the power board.
8
Lightning 11 times Communication error
between P.C. boards
The communication protection stop between boards is continu-
ously performed twice.
• Check the connecting wire be-
tween outdoor electronic control
P.C. board and power board.
9
Lightning 12 times
Zero cross detecting
circuit
The protection stop of the zero cross detecting circuit is con-
tinuously performed 10 times.
• Check the connecting wire among
outdoor electronic control P.C.
board, noise fi lter P.C. board and
power board.
10
Outdoor unit
stops and
restarts 3
minutes later'
is repeated.
Twice Goes out
IPM protection
Over-current is detected after 30 minutes of compressor start-
up.
• Reconnect compressor connector.
• Refer to 9-5. "How to check in-
verter/compressor".
• Check the stop valve.
• Check the power module (PAM
module).
Lock protection
Over-current is detected within 30 minutes of compressor start-
up.
11
3 times Goes out Discharge temperature
protection
Discharge temperature exceeds 116°C during operation and
compressor stops. Compressor can restart if discharge tem-
perature thermistor reads 100°C or less 3 minutes later.
• Check the amount of gas and re-
frigerant circuit.
• Refer to 9-5. "Check of LEV".
12
4 times Goes out Fin temperature protec-
tion
The fi n temperature exceeds 87°C during operation.
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 9-5. "Check of outdoor
fan motor".
P.C. board temperature
protection
The P.C. board temperature exceeds 70°C during operation.
5 times Goes out High-pressure protec-
tion
High-pressure is detected with the high-pressure switch (HPS)
during operation.
• Check around of gas and the re-
frigerant circuit.
• Check of stop valve.
13
The outdoor heat exchanger temperature exceeds 70°C during
cooling or indoor gas pipe temperature exceeds 70°C during
heating.
14
8 times Goes out Converter protection A failure is detected in the operation of the converter during op-
eration.
• Replace the power board.
15
9 times Goes out Bus-bar voltage protec-
tion (1)
The bus-bar voltage exceeds 400 V or falls to 200 V or below
during compressor operating.
• Replace the power board.
Bus-bar voltage protec-
tion (2)
The bus-bar voltage exceeds 400 V or falls to 50 V or below
during compressor operating.
16
13 times Goes out Outdoor fan motor Failure occurs continuously 3 times within 30 seconds after the
fan gets started.
• Refer to 9-5. "Check of outdoor
fan motor".
17
Lighting 8 times Current sensor protec-
tion
A short or open circuit is detected in the current sensor during
compressor operating.
• Replace the power board.
18
Lighting 11 times Communication be-
tween P.C. boards pro-
tection
Communication error occurs between the outdoor electronic
control P.C. board and power board for more than 10 seconds.
• Check the connecting wire be-
tween outdoor electronic control
P.C. board and power board.
19
Lighting 12 times Zero cross detecting
circuit protection Zero cross signal cannot be detected while the compressor is
operating.
• Check the connecting wire among
outdoor electronic control P.C.
board, noise fi lter P.C. board and
power board.
NOTE : 1. The location of LED is illustrated at the right fi gure. Refer to 9-6.2.
2. LED is lighted during normal operation.
The fl ashing frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the fl ashing frequency is "2".
Outdoor electronic control P.C. board(Parts side)
Lighting
LED2 LED1
ON
OFF
2.5-second OFF
2.5-second OFF
0.5-second ON
0.5-second ON