Mitsubishi Electric MXZ-2B30VA Service Manual page 72

MXZ-3B/4B/5B
Symptom Indication
No.
LED1(Red) LED2(Yellow)
Outdoor unit
Lighting Once
does not
1
operate.
2 Lighting Twice
3
Lighting 3 times
4
Lighting 4 times
5 Lighting 5 times
6
Lighting 7 times
7
Lighting 8 times
8
Lighting 11 times
9
Lighting 12 times
'Outdoor unit
stops and
Twice Goes out
restarts 3
10
minutes
later' is
repeated.
3 times Goes out
11
12 4 times Goes out
13 5 times Goes out
Goes out
14 8 times
15
9 times Goes out
16 13 times Goes out
17 Lighting 8 times
Lighting 11 times
18
Lighting 12 times
19
OBH554D
Abnormal point / Condition
LEV and drain pump The indoor unit detects an abnormality in the LEV and drain pump.
Overcurrent protection cut-out operates 3 consecutive times within 1 minute
after the compressor gets started, or converter protection cut-out or bus-bar
Outdoor power system
voltage protection cut-out operates 3 consecutive 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
A short or open circuit is detected in the thermistor during operation.
thermistor
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 10
temperature thermistor
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.
Nonvolatile memory data The nonvolatile memory data cannot be read properly.
Current sensor protection stop is continuously performed twice.
Current sensor
Communication error Communication error occurs twice between the outdoor electronic control
P.C. board and power board for more than 10 seconds.
between P.C. boards
Zero cross detecting
The protection cut-out of the zero cross detecting circuit is continuously
circuit
performed 10 times.
Overcurrent is detected after 30 seconds of compressor start-up.
IPM protection
Overcurrent is detected within 30 seconds of compressor start-up
Lock protection
Discharge temperature Discharge temperature exceeds 116°C during operation. Compressor can
protection restart if discharge temperature thermistor reads 100°C or less 3 minutes
later.
Fin temperature
The fin temperature exceeds 89°C during operation.
protection
P.C. board temperature The P.C. board temperature exceeds 87°C during operation.
protection
High-pressure
High-pressure is detected with the high-pressure switch (HPS) during
protection
operation. (MXZ-3B68/4B71/4B80/5B100VA)
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.
Bus-bar voltage
The bus-bar voltage exceeds 400 V or falls to 200 V or below during
protection (1)
compressor operating.
Bus-bar voltage
The bus-bar voltage exceeds 400 V (MXZ-3B54/3B68/4B71VA)/
protection (2)
430 V (MXZ-4B80/5B100VA) or falls to 50 V or below during
compressor operating.
Failure occurs operates 3 consecutive times within 30 seconds after
Outdoor fan motor
the fan gets started.
Current sensor
A short or open circuit is detected in the current sensor during compressor
protection
operating.
Communication protection Communication error occurs between the outdoor electronic control P.C.
between P.C. boards board and power board for more than 10 seconds.
Zero cross detecting circuit
Zero cross signal cannot be detected while the compressor is operating.
protection
Condition
72
Remedy
• Refer to 11-6. "Check of LEV".
• Check the drain pump of the indoor unit.
• 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".
• 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 the 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.