Troubleshooting Check Table - Mitsubishi Electric MUZ-GA50VA-E1 Service Manual

11-4. TROUBLESHOOTING CHECK TABLE

Indication
Symptom
No.
LED1(Red) LED2(Yellow)
Outdoor unit
does not
1
operate.
Lightning Twice
Lightning 3 times
2
Lightning 4 times
3
4
Lightning 5 times
5 Lightning 6 times
6
Lightning 7 times
7
Lightning 8 times
Lightning 11 times
8
9
Lightning 12 times
'Outdoor unit
stops and
restarts 3
minutes Twice Goes out
10
later' is
repeated.
3 times Goes out
11
4 times Goes out
12
13 5 times Goes out
14 8 times Goes out
15 9 times Goes out
16 13 times Goes out
17 Lighting 8 times
Lighting 11 times
18
Lighting 12 times
19
NOTE 1. The location of LED is illustrated at the right figure. Refer to 11-7.1.
2. LED is lighted during normal operation.
The flashing frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the flashing frequency is "2".
ON
2.5-second OFF
OFF
Abnormal point/Condition
Overcurrent protection stop is continuously performed 3 times within 1
minute after the compressor gets started, or when converter protection
Outdoor power system
stop or bus-bar voltage protection stop is continuously performed 3 times
within 3 minutes after start-up.
A short circuit is detected in the thermistor during operation, or an open
Discharge temperature
circuit is detected in the thermistor after 10 minutes of compressor start-up.
thermistor
Fin temperature thermistor
A short or open circuit is detected in the thermistor during operation.
P.C board temperature
thermistor
Ambient temperature thermistor
A short or open circuit is detected in the thermistor during operation.
A short circuit is detected in the thermistor during operation, or an open
Outdoor heat exchanger
circuit is detected in the thermistor after 5 minutes (in cooling) and
temperature thermistor
10 minutes (in heating) of compressor start-up.
A short circuit is detected in the thermistor during operation, or an open
Defrost thermistor
circuit is detected in the thermistor after 5 minutes of compressor start-up.
Serial signal
The communication fails between the indoor and outdoor unit for 3 minutes.
Nonvolatile memory data The nonvolatile memory data cannot be read properly.
Current sensor protection stop is continuously performed twice.
Current sensor
The communication protection stop between boards is continuously
Communication error between
performed twice.
P.C. boards
Zero cross detecting circuit
The protection stop of the zero cross detecting circuit is continuously
performed 10 times.
Overcurrent is detected after 30 seconds of compressor start-up.
IPM protection
Lock protection Overcurrent is detected within 30 seconds of compressor start-up.
Discharge temperature Discharge temperature exceeds 116°C during operation and compressor
stops. Compressor can restart if discharge temperature thermistor reads
protection
100°C or less 3 minutes later.
Fin temperature protection
The fin temperature exceeds 87°C during operation.
P.C. board temperature
The P.C. board temperature exceeds 70°C during operation.
protection
High-pressure protection High-pressure is detected with the high-pressure switch (HPS) during
operation.
The outdoor heat exchanger temperature exceeds 70°C during 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.
The bus-bar voltage exceeds 400V or falls to 200V or below during
Bus-bar voltage protection (1)
compressor operating.
The bus-bar voltage exceeds 400V or falls to 50V or below during
Bus-bar voltage protection (2)
compressor operating.
Failure occurs continuously 3 times within 30 seconds after the fan gets
Outdoor fan motor
started.
Current sensor protection A short or open circuit is detected in the current sensor during compressor
operating.
Communication error occurs between the outdoor electronic control P.C.
Communication between P.C.
board and power board for more than 10 seconds.
boards protection
Zero cross detecting circuit
Zero cross signal cannot be detected while the compressor is operating.
protection
Condition
0.5-second ON
2.5-second OFF
33
Remedy
• Check the connection of the compressor connecting wire.
• Refer to 11-6. "How to check inverter/compressor".
• Check the stop valve.
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6. "Check of outdoor thermistors".
• Replace the outdoor electronic control P.C. board.
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6. "How to check mis-wiring and serial signal
error".
• Replace the outdoor electronic control P.C. board.
• Replace the power board.
• Check the connecting wire between outdoor electronic control
P.C. board and power board.
• Check the connecting wire among outdoor electronic control
P.C. board, noise filter P.C. board and power board.
• Reconnect compressor connector.
• Refer to 11-6. "How to check inverter/compressor".
• Check the stop valve.
• Check the power module (PAM module).
• Check the amount of gas and refrigerant circuit.
• Refer to 11-6. "Check of LEV".
•Check refrigerant circuit and refrigerant amount.
•Refer to 11-6. "Check of outdoor fan motor".
• Check the amount of gas and the refrigerant circuit.
• Check stop valve.
• Replace the power board.
• Check the voltage of power supply.
• Replace the power board or the outdoor electronic
control P.C. board.
• Refer to 11-6. "Check of bus-bar voltage".
• Refer to 11-6. "Check of outdoor fan motor".
• Replace the power board.
• Check the connecting wire between outdoor electronic control
P.C. board and power board.
• Check the connecting wire among outdoor electronic control
P.C. board, noise filter P.C. board and power board.
Outdoor electronic control P.C. board (Parts side)
Lighting
0.5-second ON
LED2 LED1