Mitsubishi Electric MXZ-3C54VA Service Manual page 61

MXZ-6C
Indication
No. Symptom
LED1(Red) LED2(Yellow)
1 Outdoor
Lighting
unit does
not operate.
2
Lighting
3
Lighting
4
Lighting
5
Lighting
6
Lighting
7
Lighting
8
Lighting
9
Lighting
Lighting
10 'Outdoor
unit stops
and restarts
Twice
3 minutes
later' is
repeated.
11
3 times
12
4 times
13
5 times
7 times
15
9 times
10 times Goes out
11 times Goes out
12 times Goes out
16
13 times Goes out
Abnormal point /
Condition
Once LEV and drain pump
Outdoor power
Twice
system
Discharge
3 times temperature
thermistor
Fin temperature
thermistor
4 times
P.C board
temperature
thermistor
Ambient temperature
thermistor
Outdoor heat
5 times exchanger
temperature
thermistor
Defrost thermistor
Nonvolatile memory
7 times
data
8 times Current sensor
Communication error
11 times
between P.C. boards
Zero cross detecting
12 times
circuit
Nonvolatile memory
14 times
data
IPM protection
Goes out
Overcurrent
Discharge
Goes out temperature
protection
Fin temperature
protection
Goes out
P.C. board
temperature
protection
High-pressure
Goes out
protection
Out-of-step
Goes out
protection
Bus-bar voltage
Goes out
protection
Zero cross loss
Low out side
temperature
protection (cooling)
Primary current
protection
Outdoor fan motor
Condition
The indoor unit detects any abnormality in the
LEV and drain pump.
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.
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.
A short or open circuit is detected in the
thermistor during operation.
A short or open circuit is detected in the
thermistor during operation.
The nonvolatile memory data cannot be read
properly.
Current sensor has been short or open
circuited for 120 seconds.
Communication error occurs twice between the
outdoor 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.
The nonvolatile memory data cannot be read
properly.
Overcurrent is detected when the frequency
of the compressor is 1 Hz or less.
Overcurrent is detected when the frequency
of the compressor is more than 1 Hz.
Discharge temperature exceeds 114°C during
operation. Compressor can restart if discharge
temperature thermistor reads 100°C or less 3
minutes later.
The fin temperature exceeds 110°C during
operation.
The P.C. board temperature exceeds 95°C
during operation.
High-pressure is detected with the high-
pressure switch (HPS) during operation.
The outdoor heat exchanger temperature
exceeds 70°C during cooling or indoor gas
pipe temperature exceeds 70°C during
heating.
The waveform of compressor current is distorted. • Reconnect connector of compressor.
The bus-bar voltage exceeds 400 V or falls to
300 V or below while the compressor is
operating.
Zero cross signal cannot be detected while
the compressor is operating.
The ambient temperature became - 25°C or
less.
The primary current exceeds 37 A for 10
seconds.
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.
61
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".
• Replace the power board.
• Replace the power board.
• Refer to 11-6. "Check of outdoor
thermistors".
• Replace the outdoor control P.C. board.
• Replace the power board.
• Check the connecting wire between outdoor
control P.C. board and power board.
• Check the connecting wire between outdoor
control P.C. board and power board.
• Replace the 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.
• Check the amount of gas and the
refrigerant circuit.
• Check the stop valve.
• Refer to 11-6. "How to check inverter/
compressor".
• Check the voltage of power supply.
• Replace the power board or the outdoor
control P.C. board.
• Refer to 11-6. "Check of bus-bar voltage".
• Refer to 11-6. "Check of outdoor fan motor".