87 Operation start
Check the outdoor unit LED indicator.
Refer to 11-6.
"Check of power supply".
• When cooling, dew drops in the non-operating indoor unit.
Check of mispiping
• Indoor unit serial signal error
Refer to 11-6.
"How to check miswiring and serial signal error".
• COOL or HEAToperation only Refer to 11-6.
"Check of R.V. coil".
• When cooling, room does not cool.
Refer to 11-6.
"How to check of inverter/
compressor".
• When cooling, heat exchanger of non-operating indoor unit frosts.
•When heating, non- operating indoor unit gets warm.
Refer to 11-6.
"Check of LEV".
• When heating, room does not get warm.
Refer to 11-6.
"How to check of inverter/compressor".
Check mispiping, shortage of capacity
Refer to 11-4.
"Troubleshooting check table".
Both LED 1 and
LED 2 are lighting. LED 1 or LED 2
has blinked.
Both LED 1 and LED 2 are OFF.
88 MXZ-2C
No.
1
2
3
4
5
6
8
9
10
11
12 13 14
15 Symptom
'Outdoor unit stops and restarts 3 minutes later' is repeated.
Primary current protection Secondary current protection High-pressure protection Defrosting in cooling
3 times Lighted Discharge temperature protection
4 times Lighted Low discharge temperature protection
• Check refrigerant circuit and refrigerant amount.
• Refer to 11-6. "Check of LEV".
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6. "Check of LEV".
• Check refrigerant circuit and refrigerant amount.
These symptoms do not mean any abnormality of the product, but check the following points.
• Check if indoor filters are clogged.
• Check if refrigerant is short.
• Check if indoor/outdoor unit air circulation is short cycled.
Twice Lighted Once Lighted
The discharge temperature exceeds 100°C during operation.
The frequency of the compressor is kept 68 Hz (MXZ-2C30VA, MXZ-2C40 VA)/80 Hz (MXZ-2C52VA) or more and the discharge temperature is kept under 50°C (COOL mode)/40°C (HEAT mode) for more than 40 minutes.
The input current exceeds 8 A (MXZ-2C30VA)/ 10 A (MXZ-2C40VA, MXZ-2C52VA).
The current of the compressor exceeds 17 A.
The indoor gas pipe temperature exceeds 45°C during heating.
The indoor gas pipe temperature falls 3°C or below during cooling.
Outdoor unit operates.
16
17
18
19 7
LED1(Red) LED2(Yellow)
Lighted Twice Outdoor power system
Lighted 3 times Discharge temperature thermistor
Outdoor heat exchanger temperature thermistor
Defrost thermistor
Lighted 7 times Nonvolatile memory data • Replace the inverter P.C. board.
Abnormal point / Condition Remedy
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.
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.
• Replace the inveter P.C. board.
Indication
Overcurrent protection cut-out operates 3 consecutive times within 1 minute after the compressor gets started.
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
The nonvolatile memory data cannot be read properly.
Fin temperature thermistor P.C board temperature thermistor Lighted 4 times
Ambient temperature thermistor
A short or open circuit is detected in the thermistor during operation.
A short or open circuit is detected in the thermistor during operation.
5 times Lighted
Overcurrent
3 times Not lighted
Discharge temperature protection Fin temperature protection P.C. board temperature protection High-pressure protection
• Replace the inverter P.C. board.
Bus-bar voltage protection Outdoor fan motor 8 times Current sensor
protection • Replace the inverter P.C. board.
Not lighted Compressor
• 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 amount of gas and the refrigerant circuit.
• Check the 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.
Twice Not
lighted
4 times Not lighted
5 times Not lighted 9 times Not lighted
14 A (MXZ-2C30VA)/18 A (MXZ-2C40VA, MXZ-2C52VA) current flows into intelligent power module.
The bus-bar voltage exceeds 430 V or falls to 50 V or below during compressor operating.
Discharge temperature exceeds 116°C during operation. Compressor can restart if discharge temperature thermistor reads 100°C or less 3 minutes later.
The fin temperature exceeds 90°C during operation.
The P.C. board temperature exceeds 78°C during operation.
Failure occurs 3 consecutive times within 30 seconds after the fan gets started.
A short or open circuit is detected in the current sensor during compressor operating.
The compressor does not synchronize with the operating power.
The outdoor heat exchanger temperature exceeds 70°C during cooling or indoor gas pipe temperature exceeds 70°C during heating.
Outdoor unit does not
operate. Lighted Once LEV and drain pump
• 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".
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6 "Check of LEV".
• Check the drain pump of the indoor unit.
The indoor unit detects an abnormality in the LEV and drain pump.
Lighted 11 times Stop valve
Closed valve Closed valve is detected by compressor current.
(MXZ-2C30VA, MXZ-2C40VA) • Check the stop valve.
13 times
10 times
Not lighted Not lighted
89
-
- 9 times Lighted Inverter check mode
Lighted Lighted Normal
The connector of compressor is disconnected.
Inverter check mode starts.
- 5 times Lighted Cooling high-pressure
protection
This symptom does not mean any abnormality of the product, but check the following points.
• Check if indoor filters are clogged.
• Check if refrigerant is short.
• Check if indoor/outdoor unit air circulation is short cycled.
The outdoor heat exchanger temperature exceeds 58°C during operation.
20
LED1(Red) LED2(Yellow)Indication Abnormal point / Condition Condition Remedy
No. Symptom
Outdoor unit operates normally.
21
22
Outdoor unit operates.
Display P.C. board (Parts side) Lighting
LED1 LED2 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 11-7.6.
2. LED is lighted during normal operation.
90
LED1(Red) LED2(Yellow)
Lighted Twice Outdoor power system
Lighted 3 times Discharge temperature thermistor
• Refer to 11-6. "Check of outdoor thermistors".
Outdoor heat exchanger temperature thermistor
Defrost thermistor
Lighted 7 times Nonvolatile memory data • Replace the electronic control P.C. board.
Lighted 8 times Current sensor • Replace the power board.
Lighted 11 times Communication error
between P.C. boards • Check the connecting wire between electronic control
P.C. board and power board.
Lighted 12 times Zero cross detecting
circuit • Check the connecting wire between electronic control
P.C. board, noise filter P.C. board and power board.
Abnormal point / Condition Remedy
A short circuit is detected in the thermistor during operation, or an open circuit is detected in the thermistor 5 minutes (in cooling) and 10 minutes (in heating) after compressor start-up.
A short circuit is detected in the thermistor during operation, or an open circuit is detected in the thermistor 5 minutes after compressor start-up.
• Replace the electronic control P.C. board.
Indication
Overcurrent protection cut-out operates 3 consecutive times within 1 minute after the compressor gets started, or converter protection or bus-bar 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 circuit is detected in the thermistor 10 minutes after compressor start-up.
Condition
The nonvolatile memory data cannot be read properly.
Fin temperature thermistor P.C board temperature thermistor Lighted 4 times
Ambient temperature thermistor
Current sensor protection cut-out operates 2 consecutive times.
Communication error occurs twice between the electronic control P.C. board and power board for more than 10 seconds.
The protection cut-out of the zero cross detecting circuit operates 10 consecutive times.
A short or open circuit is detected in the thermistor during operation.
A short or open circuit is detected in the thermistor during operation.
5 times Lighted
IPM protection Lock protection
3 times Not lighted Discharge temperature protection Fin temperature protection P.C. board temperature protection High-pressure protection
8 times Not lighted Converter protection • Replace the power board.
Bus-bar voltage
protection (1) • Check the voltage of power supply.
• Replace the power board or the electronic control P.C. board.
• Refer to 11-6. “Check of bus-bar voltage”.
Bus-bar voltage protection (2)
13 times Not lighted Outdoor fan motor • Refer to 11-6. "Check of outdoor fan motor".
Lighted 8 times Current sensor
protection • Replace the power board.
Lighted 11 times Communication protection
between P.C. boards • Check the connecting wire between electronic
control P.C. board and power board.
Lighted 12 times Zero cross detecting circuit
protection • Check the connecting wire between electronic control
P.C. board, noise filter P.C. board and power board.
• Check the amount of gas and the refrigerant circuit.
• Check the 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 Not lighted
4 times Not lighted
5 times Not lighted
9 times Not lighted
Overcurrent is detected 30 seconds after compressor start-up.
Overcurrent is detected within 30 seconds after compressor start-up.
The bus-bar voltage exceeds 400 V or falls to 200 V or below during compressor operating.
The bus-bar voltage exceeds 400 V (MXZ-3C54/3C68/4C71VA)/
430 V (MXZ-4C80/5C100VA, 4C80/5C100VA2) or falls to 50 V or below while the compressor is operating.
Discharge temperature exceeds 116°C during operation. Compressor can restart if discharge temperature thermistor reads 100°C or less 3 minutes later.
The fin temperature exceeds 89°C during operation.
The P.C. board temperature exceeds 73°C (MXZ-3C54/3C68/4C71VA)/
87°C(MXZ-4C80/5C100VA, 4C80/5C100VA2) during operation.
High-pressure is detected with the high-pressure switch (HPS) during operation.(MXZ-3C68/4C71/4C80/5C100VA, 4C80/5C100VA2)
Failure occurs 3 consecutive times within 30 seconds after the fan gets started.
A short or open circuit is detected in the current sensor while the compressor is operating.
Communication error occurs between the electronic control P.C. board and power board for more than 10 seconds.
Zero cross signal cannot be detected while the compressor is operating.
The outdoor heat exchanger temperature exceeds 70°C during cooling or indoor gas pipe temperature exceeds 70°C during heating.
A failure is detected in the operation of the converter during operation.
Outdoor unit does not
operate. Lighted Once LEV and drain pump
• 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".
• Refer to 11-6. "Check of LEV".
• Check the drain pump of the indoor unit.
The indoor unit detects an abnormality in the LEV and drain pump.
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.
91
Primary current protection Secondary current protection High-pressure protection Defrosting in cooling
3 times Lighted Discharge temperature protection
4 times Lighted Low discharge temperature protection
• Check refrigerant circuit and refrigerant amount.
• Refer to 11-6. "Check of LEV".
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6. "Check of LEV".
• Check refrigerant circuit and refrigerant amount.
5 times Lighted Cooling high-pressure protection
This symptom does not mean any abnormality of the product, but check the following points.
• Check indoor filters are not clogged.
• Check there is sufficient refrigerant.
• Check indoor/outdoor unit air circulation is not short cycling.
-
-
These symptoms do not mean any abnormality of the product, but check the following points.
• Check indoor filters are not clogged.
• Check there is sufficient refrigerant.
• Check indoor/outdoor unit air circulation is not short cycling.
Twice Lighted Once Lighted
The outdoor heat exchanger temperature exceeds 58°C during operation.
9 times Lighted Inverter check mode
Lighted Lighted Normal
The unit is operated with emergency operation switch.
-
The primary current exceeds 15 A (MXZ-3C54/3C68/4C71VA)/
17 A (MXZ-4C80VA, 4C80VA2)/18 A (MXZ-5C100VA, 5C100VA2).
The current of the compressor exceeds 12 A (MXZ-3C54VA) /12.5A (MXZ-3C68/4C71VA) /10 A (MXZ-4C80/5C100VA, 4C80/5C100VA2).
The indoor gas pipe temperature exceeds 45°C during heating.
The indoor gas pipe temperature falls 3°C or below during cooling.
The discharge temperature exceeds 100°C during operation.
The frequency of the compressor is kept 80 Hz or more and the discharge temperature is kept under 50°C (cooling) /40°C (heating) for more than 40 minutes.
Outdoor electronic control P.C. board (Parts side)
LED2 LED1 Lighting
LED1 LED2 Lighting
MXZ-3C54/3C68/4C71VA
MXZ-4C80/5C100VA
LED1(Red) LED2(Yellow)Indication Abnormal point / Condition Condition Remedy
No.
20
21
22
23
24
25
26
Outdoor unit operates normally.
Outdoor unit operates.
Symptom
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 11-7.2.
2. LED is lighted during normal operation.
92
No. Symptom Indication Abnormal point /
Condition Condition Remedy
LED1(Red) LED2(Yellow) 1 Outdoor
unit does not operate.
Lighted Once LEV and drain pump The indoor unit detects an abnormality in the LEV
and drain pump. • Refer to 11-6. "Check of LEV".
• Check the drain pump of the indoor unit.
2
Lighted Twice Outdoor power system
Overcurrent protection cut-out operates 3 consecutive times, bus-bar voltage protection cut- out operates 3 consecutive times, or primary current protection cut-out operates 3 consecutive times within 1minute after the compressor gets started.
• Check the connection of the compressor connecting wire.
• Refer to 11-6. "How to check inverter/
compressor".
• Check the stop valve.
3 Lighted 3 times Discharge
temperature thermistor
A short circuit is detected in the thermistor during operation, or an open circuit is detected in the thermistor 10 minutes after compressor start-up.
• Refer to 11-6. "Check of outdoor thermistors".
4
Lighted 4 times
Fin temperature
thermistor A short or open circuit is detected in the
thermistor during operation. • Replace the power board (MXZ-6C120VA)/
outdoor power P.C. board (MXZ-6C122VA).
P.C board temperature thermistor
• Replace the power board (MXZ-6C120VA)/
outdoor power P.C. board (MXZ-6C122VA).
5
Lighted 5 times
Ambient temperature
thermistor A short or open circuit is detected in the
thermistor during operation. • Refer to 11-6. "Check of outdoor thermistors".
Outdoor heat exchanger temperature thermistor Defrost thermistor
6 Lighted 7 times Nonvolatile memory
data (Outdoor control P.C. board)
The nonvolatile memory data cannot be read
properly. • Replace the control P.C. board (MXZ-6C120VA)/
outdoor control P.C. board(MXZ-6C122VA).
7 Lighted 8 times Current sensor Current sensor has been short or open circuited
for 120 seconds. • Replace the power board (MXZ-6C120VA)/
outdoor power P.C. board(MXZ-6C122VA).
8
Lighted 11 times Communication error between P.C. boards
Communication error occurs twice between the outdoor control P.C. board an dpower board (MXZ- 6C120VA)/outdoor power P.C. board (MXZ- 6C122VA) for more than 10 seconds.
• Check the connecting wire between control P.C.
board (MXZ-6C120VA)/outdoor control P.C.
board(MXZ-6C122VA) and power board (MXZ- 6C120VA)/outdoor power P.C. board (MXZ- 6C122VA).
9
Lighted 12 times Zero cross detecting circuit
The protection cut-out of the zero cross detecting
circuit operates 3 consecutive times. • Check the connecting wire between control P.C.
board (MXZ-6C120VA)/outdoor control P.C.
board(MXZ-6C122VA) and power board (MXZ- 6C120VA)/outdoor power P.C. board (MXZ- 6C122VA).
Lighted 14 times
Nonvolatile memory data (power board (MXZ- 6C120VA)/outdoor power P.C. board (MXZ-6C122VA))
The nonvolatile memory data cannot be read
properly. • Replace the power board (MXZ-6C120VA)/
outdoor power P.C. board (MXZ-6C122VA).
10 'Outdoor unit stops and restarts 3 minutes later' is repeated.
Twice Not lighted IPM protection Overcurrent is detected when the frequency of the
compressor is 1 Hz or less. • Reconnect compressor connector.
• Refer to 11-6. "How to check inverter/
compressor".
• Check the stop valve.
• Check the power module (PAM module).
Overcurrent Overcurrent is detected when the frequency of the compressor is more than 1 Hz.
11
3 times Not lighted Discharge temperature protection
Discharge temperature exceeds 114°C during operation. Compressor can restart if discharge temperature thermistor reads 100°C or less 3 minutes later.
• Check the amount of gas and refrigerant circuit.
• Refer to 11-6. "Check of LEV".
12
4 times Not lighted
Fin temperature
protection The fin temperature exceeds 110°C during
operation. •Check refrigerant circuit and refrigerant
amount.
P.C. board temperature protection
The P.C. board temperature exceeds 95°C during operation.
13
5 times Not lighted High-pressure protection
High-pressure is detected with the high-pressure
switch (HPS) during operation. • Check the amount of gas and the refrigerant circuit.
• Check the stop valve.
The outdoor heat exchanger temperature exceeds 70°C during cooling or indoor gas pipe temperature exceeds 70°C during heating.
7 times Not lighted Out-of-step protection
The waveform of compressor current is distorted. • Reconnect connector of compressor.
• Refer to 11-6. "How to check inverter/
compressor".
15
9 times Not lighted Bus-bar voltage protection
The bus-bar voltage exceeds 400 V or falls to 300 V or below while the compressor is operating.
• Check the voltage of power supply.
• Replace the power board (MXZ-6C120VA)/
outdoor power P.C. board (MXZ-6C122VA) or the control P.C. board (MXZ-6C120VA)/outdoor control P.C. board (MXZ-6C122VA) .
• Refer to 11-6. “Check of bus-bar voltage”.
10 times Not lighted Zero cross loss Zero cross signal cannot be detected while the compressor is operating.
11 times Not lighted Low out side temperature protection (cooling)
The ambient temperature became -12°C or less.
12 times Not lighted Primary current protection The primary current exceeds 37 A for 10 seconds.
16
13 times Not lighted Outdoor fan motor
The fan motor speed is 50 rpm or less or 1500 rpm or more for 1 minute, or the fan motor speed is 100 rpm or less for 15 seconds when the outside temperature is 20 °C or more.
• Refer to 11-6. "Check of outdoor fan motor".
93
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 11-7.3.
2. LED is lighted during normal operation.
No. Symptom Indication Abnormal point /
Condition Condition Remedy
LED1(Red) LED2(Yellow) 17 'Outdoor
unit stops and restarts 3 minutes later' is repeated.
Lighted 8 times Current sensor protection
After the operation starts, a short or open circuit is detected in the current sensor when the compressor is not operating.
• Replace the power board (MXZ-6C120VA)/
outdoor power P.C. board (MXZ-6C122VA).
18
Lighted 11 times Communication protection between P.C. boards
Communication error occurs between the control P.C. board (MXZ-6C120VA)/outdoor control P.C.
board (MXZ-6C122VA) and power board (MXZ- 6C120VA)/outdoor power P.C. board (MXZ- 6C122VA) for more than 10 seconds.
• Check the connecting wire between control P.C.
board (MXZ-6C120VA)/outdoor control P.C.
board (MXZ-6C122VA) and power board (MXZ- 6C120VA)/outdoor power P.C. board (MXZ- 6C122VA).
19
Lighted 12 times Zero cross detecting circuit protection
Zero cross signal cannot be detected when the
compressor begins operating. • Check the connecting wire between outdoor control P.C. board (MXZ-6C120VA)/outdoor control P.C. board (MXZ-6C122VA) and power board (MXZ-6C120VA)/outdoor power P.C. board (MXZ-6C122VA) .
20 Outdoor unit operates
Once Lighted Primary current protection
The primary current exceeds 27A. These symptoms do not mean any abnormality of the product, but check the following points.
• Check indoor f lters are not clogged.
• Check there is suff cient refrigerant.
• Check indoor/outdoor unit air circulation is not short cycling.
21
Twice Lighted
High-pressure
protection The indoor heat exchanger exceeds 38°C during heating.
Defrosting in cooling The indoor heat exchanger falls 3°C or below during cooling.
22 3 times Lighted Discharge
temperature protection
The discharge temperature exceeds 100°C during
operation. • Check refrigerant circuit and refrigerant amount.
• Refer to 11-6. "Check of LEV".
23 4 times Lighted Low discharge
temperature protection
The frequency of the compressor is kept 58 Hz or more and the discharge temperature is kept under 50°C (cooling) /40°C (heating) for more than 20 minutes
• Refer to 11-6. "Check of LEV".
• Check refrigerant circuit and refrigerant amount.
24
5 times Lighted Cooling high- pressure protection
The outdoor heat exchanger temperature exceeds
54°C during operation. This symptom does not mean any abnormality of the product, but check the following points.
• Check indoor f lters are not clogged.
• Check there is suff cient refrigerant.
• Check indoor/outdoor unit air circulation is short cycling.
7 times Lighted
High Low Pressure bypass valve
Cooling evaporating temperature drop prevention control
During cooling operation, the temperature of indoor heat exchanger becomes 3°C or less within 1 hour after the compressor starts running, or it becomes less than 12°C - 16°C* later than that.
* It depends on the difference between the set temperature and the room temperature.
This symptom does not mean any abnormality of the product, but check the following points.
• Check indoor f lters are not clogged.
• Check there is suff cient refrigerant.
• Check indoor/outdoor unit air circulation is not short cycling.
25 Outdoor unit operates normally.
7 times Lighted
High Low pressure bypass valve
High pressure protection control at start-up of heating operation
The room temperature is 24°C or more when 1 or
2 unit(s) start(s) the heating operation. This symptom does not mean any abnormality of the product.
High Low pressure bypass valve
Compressor oil tempering control at start-up of heating operation
Both the following are true:
• The outside temperature is -2°C or less when the heating operation is started.
• [(Discharge temperature) - (Indoor heat exchanger temperature)] < 5°C
8 times Lighted Cooling evaporating temperature protection
During cooling operation, the temperature of indoor heat exchanger becomes 7°C - 11°C*
or less within 1 hour after the compressor starts running, or it becomes 9°C - 17°C* or less later than that.
* It depends on the indoor unit type/model or the difference between the set temperature and the room temperature.
9 times Lighted Inverter check mode
The connector of compressor is disconnected.
Inverter check mode starts.
• Check the connector of the compressor is correctly connected.
• Refer to 11-6. "How to check inverter/
compressor".
26 Lighted Lighted Normal
Outdoor control P.C. board (Parts side) LED1
LED2 Lighting