Troubleshooting Check Table - Mitsubishi Electric MUZ-GB50VA Service Manual

11-3. TROUBLESHOOTING CHECK TABLE

MUZ-GB50VA- /
E1
LED indication
No. Symptom
LED1(Red) LED2(Yellow)
Outdoor unit
does not oper-
1 ate. Lightning
2 Lightning 3 times
3 Lightning 4 times
4 Lightning 5 times
5 Lightning 6 times
6 Lightning 7 times
7 Lightning 8 times
8 Lightning 11 times
9 Lightning 12 times
'Outdoor unit
stops and
restarts 3 min-
utes later' is
10 Twice Goes out
repeated.
11 3 times Goes out
12 4 times Goes out
13 5 times Goes out
14 8 times Goes out
15 9 times Goes out
16 13 times Goes out
17 Lighting 8 times
18 Lighting 11 times
19 Lighting 12 times
NOTE: 1. The location of LED is illustrated at the right fi gure. Refer to 10-6.1.
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".
ON
2.5-second OFF
OFF
E2
Abnormal point/ Con-
dition
Outdoor power system Overcurrent protection stop is continuously performed 3 times
within 1 minute after the compressor gets started, or when
Twice converter protection stop or bus-bar voltage protection stop is
continuously performed three times within 3 minutes after start-
up.
Discharge temperature A short circuit is detected in the thermistor during operation, or
thermistor when an open circuit is detected in the thermistor after 10 min-
utes of compressor start-up.
Fin temperature A short or open circuit is detected in the thermistor during op-
thermistor eration.
P.C. board tempera-
ture thermistor
Ambient temperature A short or open circuit is detected in the thermistor during op-
thermistor eration.
Outdoor heat exchanger A short circuit is detected in the thermistor during operation, or
temperature thermistor 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 stat-up.
Serial signal The communication fails between the indoor and outdoor unit 3
minutes.
Nonvolatile memory The nonvolatile memory data cannot be read properly.
data
Current sensor Current sensor protection stop is continuously performed twice. • Replace the power board.
Communication error The communication protection stop between boards is continu-
between P.C. boards ously performed twice.
Zero cross detecting The protection stop of the zero cross detecting circuit is con-
circuit tinuously performed 10 times.
lPM protection Overcurrent is detected after 30 seconds of compressor start-
up.
Lock protection Overcurrent is detected within 30 seconds of compressor start-
up.
Discharge tempera- Discharge temperature exceeds 116°C during operation and
ture protection compressor stops. Compressor can restart if discharge tem-
perature thermistor reads 100°C or less 3 minutes later.
Fin temperature pro- The fi n temperature exceeds 87°C during operation.
tection
P.C. board temperature The P.C. board temperature exceeds 70°C during operation.
protection
High-Pressure pro- The outdoor heat exchanger temperature exceeds 70°C during
tection cooling or indoor gas pipe temperature exceeds 70°C during
heating.
Converter protection A failure is detected in the operation of the converter during
operation.
Bus-bar voltage pro- The bus-bar voltage exceeds 400 V or falls to 200 V or below
tection (1). during compressor operating.
Bus-bar voltage pro- The bus-bar voltage exceeds 400 V or falls to 50 V or below
tection (2) during compressor operating.
Outdoor fan motor Failure occurs continuously three times within 30 seconds after
the fan gets started.
Current sensor pro- A short or open circuit is detected in the current sensor during
tection compressor operating.
Communication be- Communication error occurs between the outdoor electronic
tween P.C. boards control P.C. board and power board for more than 10 seconds
protection
Zero cross detecting Zero cross signal cannot be detected while the compressor is
circuit protection operating.
Condition
Outdoor electronic control P.C. board (Parts side)
0.5-second ON
2.5-second OFF
23
Remedy
• Check the connection of the com-
pressor connecting wire.
• Refer to 11-5. "How to check in-
verter/compressor".
• Check the stop valve.
• Refer to 11-5. "Check of outdoor
thermistors".
• Refer to 11-5. "Check of outdoor
thermistors".
• Replace the outdoor electronic
control P.C. board.
• Refer to 11-5. "Check of outdoor
thermistors".
• Refer to 11-5. "How to check
miswiring and serial signal error.
• Replace the outdoor electronic
control P.C. board.
• Check the connecting wire be-
tween outdoor electronic control
P.C. board and power board.
• Check the connecting wire among
outdoor electronic control P.C.
board, noise fi lter P.C. board and
power board.
• Reconnect compressor connector.
• Refer to 11-5. "How to check in-
verter/compressor".
• Check the stop valve.
• Check the power module (PAM
module).
• Check the amount of gas and re-
frigerant circuit.
• Refer to 11-5. "Check of LEV".
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 11-5. "Check of outdoor
fan motor".
• Check the amount of gas and the
refrigerant circuit.
• Check the stop valve.
• Replace the power board.
• Check the voltage of power supply.
• Replace the power board or the out-
door electronic control P.C. board.
• Refer to 11-5. "Check of bus-bar
voltage".
• Refer to 11-5. "Check of outdoor
fan motor".
• Replace the power board.
• Check the connecting wire be-
tween outdoor electronic control
P.C. board and power board.
• Check the connecting wire among
outdoor electronic control P.C.
board, noise fi lter P.C. board and
power board.
Lighting
0.5-second ON
LED2 LED1