Troubleshooting Check Table - Mitsubishi Electric MXZ-2C30VA Service Manual

11-4. TROUBLESHOOTING CHECK TABLE

MXZ-2C
Symptom Indication
No.
LED1(Red) LED2(Yellow)
Outdoor unit
1 Lighting Once
does not
operate.
2
Lighting Twice
3
Lighting 3 times
4
Lighting 4 times
5 Lighting 5 times
Lighting 7 times
6
7
Lighting 11 times
'Outdoor
unit stops
Twice Goes out
and restarts
8
3 minutes
later' is
repeated.
3 times Goes out
9
10 4 times Goes out
11 5 times Goes out
12 9 times Goes out
13 13 times Goes out
14 8 times Goes out
10 times Goes out
15
Outdoor unit
operates.
16 Once
Lighting
Twice Lighting
17
18
3 times Lighting
19 4 times
Lighting
Abnormal point / Condition
The indoor unit detects any abnormality in the LEV for drain.
LEV for drain
Overcurrent protection cut-out operates 3 consecutive times
within 1 minute after the compressor gets started.
Outdoor power system
A short circuit is detected in the thermistor during operation, or when an
Discharge temperature
open circuit is detected in the thermistor after 10 minutes of compressor
thermistor
start-up.
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 when
Outdoor heat exchanger
an open circuit is detected in the thermistor after 5 minutes (in cooling)
temperature thermistor
and 10 minutes (in heating) of compressor start-up.
A short circuit is detected in the thermistor during operation, or when an
Defrost thermistor open circuit is detected in the thermistor after 5 minutes of compressor
start-up.
The nonvolatile memory data cannot be read properly.
Nonvolatile memory data
Stop valve Closed valve is detected by compressor current.
Closed valve (MXZ-2C30VA, MXZ-2C40VA)
14 A (MXZ-2C30VA)/18 A (MXZ-2C40VA, MXZ-2C52VA) current flows
Overcurrent
into intelligent power module.
Discharge temperature exceeds 116°C during operation. Compressor can
Discharge temperature
protection restart if discharge temperature thermistor reads 100°C or less 3 minutes
later.
Fin temperature
The fin temperature exceeds 90°C during operation.
protection
P.C. board temperature
The P.C. board temperature exceeds 78°C during operation.
protection
The outdoor heat exchanger temperature exceeds 70°C during cooling
High-pressure
or indoor gas pipe temperature exceeds 70°C during heating.
protection
The bus-bar voltage exceeds 430 V or falls to 50 V or below during
Bus-bar voltage
compressor operating.
protection
Failure occurs 3 consecutive times within 30 seconds after the fan
Outdoor fan motor
gets started.
Current sensor
A short or open circuit is detected in the current sensor during
protection
compressor operating.
The compressor doesn't synchronize
Compressor
with the operating power.
Primary current protection
The input current exceeds 8 A (MXZ-2C30VA)/ 10 A (MXZ-2C40VA,
MXZ-2C52VA).
Secondary current protection
The current of the compressor exceeds 17 A.
High-pressure protection
The indoor gas pipe temperature exceeds 45°C during heating.
Defrosting in cooling
The indoor gas pipe temperature falls 3°C or below during cooling.
The discharge temperature exceeds 100°C during operation.
Discharge temperature
protection
The frequency of the compressor is kept 68 Hz (MXZ-2C30VA, MXZ-2C40
Low discharge
VA)/80 Hz (MXZ-2C52VA) or more and the discharge temperature is kept
temperature protection
under 50°C (COOL mode)/40°C (HEAT mode) for more than 40 minutes.
Condition
77
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.
• Check the stop valve.
• Reconnect compressor connector.
• Refer to 11-6. "How to check inverter/compressor".
• 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".
• Check the amount of gas and the refrigerant circuit.
• Check the stop valve.
• Replace the power board.
• Refer to 11-6. "Check of outdoor fan motor".
• Replace the power board.
• Reconnect compressor connector.
• Refer to 11-6. "How to check inverter/compressor".
• Check the stop valve.
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.
• 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.