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11-4. TROUBLESHOOTING CHECK TABLE
LED2
LED1
Outdoor electronic control P.C. board (Parts side)
Lighting
LED1
LED2
Lighting
LED1(Red) LED2(Yellow)
Lighting Twice Outdoor power system
• Check the connection of the compressor connecting
wire.
• Refer to 11-6. "How to check inverter/compressor".
• Check the stop valve.
Lighting 3 times
Discharge temperature
thermistor
• Refer to 11-6. "Check of outdoor thermistors".
Outdoor heat exchanger
temperature thermistor
Defrost thermistor
Lighting 7 times Nonvolatile memory data • Replace the outdoor electronic control P.C. board.
Lighting 8 times Current sensor • Replace the power board.
Lighting 11 times
Communication error
between P.C. boards
• Check the connecting wire between outdoor electronic control
P.C. board and power board.
Lighting 12 times
Zero cross detecting
circuit
• Check the connecting wire among outdoor electronic control
P.C. board, noise filter P.C. board and power board.
Abnormal point / Condition
Correspondence
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.
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6. "Check of outdoor thermistors".
• Replace the outdoor electronic control P.C. board.
Indication
When over current 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.
Condition
When the nonvolatile memory data cannot be read properly.
Fin temperature
thermistor
P.C board temperature
thermistor
Lighting 4 times
Ambient temperature
thermistor
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.
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.
5 timesLighting
IPM protection
Lock protection
3 times Goes out
Discharge temperature
protection
Fin temperature
protection
P.C. board temperature
protection
High-pressure
protection
8 times Goes out
Converter protection
• Replace the power board.
Bus-bar voltage
protection (1)
• 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".
Bus-bar voltage
protection (2)
13 times Goes out Outdoor fan motor
• Refer to 11-6. "Check of outdoor fan motor".
Lighting 8 times
Current sensor
protection
• Replace the power board.
Lighting 11 times
Communication between P.C.
boards protection
• Check the connecting wire between outdoor electronic control
P.C. board and power board.
Lighting 12 times
Zero cross detecting circuit
protection
• Check the connecting wire among outdoor electronic control
P.C. board, noise filter P.C. board and power board.
• Check around of gas and the refrigerant circuit.
• Check of stop valve.
• 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".
• Reconnect compressor connector.
• Refer to 11-6. "How to check inverter/compressor".
• Check the stop valve.
• Check the power module (PAM module).
Twice
Goes out
4 times Goes out
5 times Goes out
9 times Goes out
When overcurrent is detected after 30 minutes of compressor start-up.
When overcurrent is detected within 30 minutes of compressor
start-up
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 discharge temperature exceeds 240.8°F during operation.
Compressor can restart if discharge temperature thermistor reads 212°F
or less 3 minutes later.
When the fin temperature exceeds 188.6°F during operation.
When the P.C. board temperature exceeds 158°F during operation.
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.
When high-pressure is detected with the high-pressure switch (HPS)
during operation.
(MXZ-3B24NA, MXZ-3B30NA, MXZ-4B36NA)
When the outdoor heat exchanger temperature exceeds 158°F
during cooling or when indoor gas pipe temperature exceeds 158°F
during heating.
When a failure is detected in the operation of the converter during
operation.
Outdoor unit
does not
operate.
Lighting Once LEV for drain
• Refer to 11-6. "Check of LEV".
• Check the drain pump of the indoor unit.
When the indoor unit detects any abnormality in the LEV for drain.
No.
1
2
3
4
5
6
7
9
8
10
11
12
13
14
15
16
17
18
19
Symptom
'Outdoor unit
stops and
restarts 3
minutes
later' is
repeated.
MXZ-2B20NA
MXZ-3B24NA, MXZ-3B30NA
MXZ-4B36NA
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
OFF
2.5-second OFF
2.5-second OFF
0.5-second ON
0.5-second ON
NOTE 1. The location of LED is illustrated at the right figure. Refer to 11-7.1.
2. LED is lighted during normal operation.