Troubleshooting Check Table - Mitsubishi Electric MUZ-GA50VA Service Manual

10-4. Troubleshooting check table

NOTE 1. The location of LED is illustrated at the right figure.
2. LED lights up during normal operation.
Indication
Abnormal point
LED1(Red) LED2(Yellow)
Lightning Twice Outdoor power system
Discharge temperature
Lightning 3 times
thermistor
Fin temperature
thermistor
Lightning 4 times
P.C board temperature
thermistor
Ambient temperature
thermistor
Outdoor heat exchanger
temperature thermistor
Lightning 5 times
Defrost thermistor
Lightning 7 times EEPROM
Lightning 8 times Current sensor
Communication error
Lightning 11 times
between P.C. boards
Zero cross detecting
Lightning 12 times
circuit
Indication
Abnormal point
LED1 LED2
IPM protection
Twice Goes out
Lock protection
Discharge temperature
3 times Goes out
protection
Fin temperature
protection
4 times Goes out
P.C. board temperature
protection
HPS protection
5 times Goes out
High-pressure
protection
Converter protection
8 times Goes out
Bus-bar voltage
protection (1)
9 times Goes out
Bus-bar voltage
protection (2)
13 times Goes out Fan protection
Current sensor
Lighting 8 times
protection
Communication between P.C.
Lighting 11 times
boards protection
Zero cross detecting circuit
Lighting 12 times
protection
Symptom: Outdoor unit does not operate.
Detecting method
When IPM protection stop or lock protection stop is continuously
performed three times within 1 minute after the compressor gets
started, or when converter protection stop or bus-bar voltage
protection stop is continuously performed three times within 3
minutes after start-up.
When a short circuit is detected in the thermistor during operation, or
when an open circuit is detected in the thermistor after 10 minutes
of compressor start-up.
When a short or open circuit is detected in the thermistor during
operation.
When a short or open circuit is detected in the thermistor during
operation.
When a short circuit is detected in the thermistor during operation, or
when an open circuit is detected in the thermistor after 5 minutes (in
cooling) and 10 minutes (in heating) of compressor start-up.
When a short circuit is detected in the thermistor during operation, or
when an open circuit is detected in the thermistor after 5 minutes of
compressor start-up.
When the nonvolatile memory data cannot be read properly.
Current sensor protection stop is continuously performed twice.
When the communication protection stop between boards is
continuously performed twice.
The protection stop of the zero cross detecting circuit is continuously
performed 10 times.
Symptom: It is repeated that outdoor unit stops and restarts 3 minutes later.
Detecting method
When over-current is detected after 30 minutes of compressor start-up.
When over-current is detected within 30 minutes of compressor
start-up
When the discharge temperature exceeds 116: during operation.
When the fin temperature exceeds 87: during operation.
When the P.C. board temperature exceeds 70: during operation.
When high-pressure is detected with the high-pressure switch (HPS)
during operation.
When the outdoor heat exchanger temperature exceeds 70:
during cooling or when indoor gas pipe temperature exceeds 70:
during heating
When a failure is detected in the operation of the converter during
operation.
When the bus-bar voltage exceeds 400V or falls to 200V or below
during compressor operating.
When the bus-bar voltage exceeds 400V or falls to 50V or below
during compressor operating.
When failure occurs continuously three times within 30 seconds after
the fan gets started.
When a short or open circuit is detected in the current sensor during
compressor operating.
Communication error occurs between the outdoor electronic control P.C.
board and power board for more than 10 seconds.
When zero cross signal cannot be detected while the compressor is
operating.
31
Outdoor electronic control P.C. board(Parts side)
Lighting
Check points
• Check the connection of the compressor connecting
wire.
• Check the inverter/compressor. (Refer to 10-6.E.)
• Check the stop valve.
• Check the power module (PAM module).
• Check the discharge temperature thermistor.
(Refer to 10-6.F.)
• Check the fin temperature thermistor.(Refer to 10-6.F.)
• Replace the outdoor electronic control P.C. board.
• Check the ambient temperature thermistor.
(Refer to 10-6.F.)
• Check the outdoor hear exchanger temperature
thermistor.
(Refer to 10-6.F.)
• Check the defrost thermistor.
(Refer to 10-6.F.)
• 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.
Check points
• Check the connection of the compressor connecting
wire.
• Check the inverter/compressor.(Refer to 10-6.E.)
• Check the stop valve.
• Check the power module.
• Check the amount of gas and refrigerant circuit.
• Check the LEV.(Refer to 10-6.D.)
• Check the surrounding of the outdoor unit.
• Check the air passage.
• Check the outdoor fan motor. (Refer to 10-6.G.)
• Check the amount of gas and the refrigerant circuit.
• Check the stop valve.
• Replace the power board.
• Replace the power board.
• Replace the power board.
• Check the outdoor fan motor.(Refer to 10-6.G.)
• 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.
LED2 LED1