Mitsubishi Electric MXZ-3C54VA, Service Manual

Page: 61 / 270

61
MXZ-6C
No. Symptom
Indication
Abnormal point /
Condition
Condition Remedy
LED1(Red) LED2(Yellow)
1 Outdoor
unit does
not operate.
Lighting Once LEV and drain pump
The indoor unit detects any abnormality in the
LEV and drain pump. • Refer to 11-6. "Check of LEV".
• Check the drain pump of the indoor unit.
2
Lighting 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
Lighting 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
Lighting 4 times
Fin temperature
thermistor A short or open circuit is detected in the
thermistor during operation. • Replace the power board.
P.C board
temperature
thermistor • Replace the power board.
5
Lighting 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
Lighting 7 times
Nonvolatile memory
data The nonvolatile memory data cannot be read
properly. • Replace the outdoor control P.C. board.
7
Lighting 8 times Current sensor
Current sensor has been short or open
circuited for 120 seconds. • Replace the power board.
8
Lighting 11 times
Communication error
between P.C. boards
Communication error occurs twice between the
outdoor control P.C. board and power board for
more than 10 seconds. • Check the connecting wire between outdoor
control P.C. board and power board.
9
Lighting 12 times
Zero cross detecting
circuit
The protection cut-out of the zero cross
detecting circuit operates 10 consecutive
times. • Check the connecting wire between outdoor
control P.C. board and power board.
Lighting 14 times
Nonvolatile memory
data The nonvolatile memory data cannot be read
properly. • Replace the power board.
10 'Outdoor
unit stops
and restarts
3 minutes
later' is
repeated.
Twice Goes out
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 Goes out
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 Goes out
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 Goes out
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 Goes out
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 Goes out
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 or the outdoor
control P.C. board.
• Refer to 11-6. “Check of bus-bar voltage”.
10 times Goes out Zero cross loss
Zero cross signal cannot be detected while
the compressor is operating.
11 times Goes out
Low out side
temperature
protection (cooling) The ambient temperature became - 25°C or
less.
12 times Goes out
Primary current
protection The primary current exceeds 37 A for 10
seconds.
16
13 times Goes out 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".