Mitsubishi Electric MXZ-2B20NA Service Manual page 63

MXZ-5B
Indication
No. Symptom
LED1(Red) LED2(Yellow)
1 Outdoor
Lighted
unit does
not operate.
2
Lighted
3
Lighted
4
Lighted
5
Lighted
6
Lighted
7
Lighted
8
Lighted
9
Lighted
Lighted
10 'Outdoor
unit stops
and restarts Twice Not lighted
3 minutes
later' is
repeated.
11
3 times Not lighted
12
4 times Not lighted
13
5 times Not lighted
7 times Not lighted
15
9 times Not lighted
10 times Not lighted
11 times Not lighted
12 times Not lighted
16
13 times Not lighted
OBH560G
Abnormal point /
Condition
Once LEV and drain pump
Twice Outdoor power system
Discharge temperature
3 times
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 (Outdoor control
P.C. board)
8 times Current sensor
Communication error
11 times
between P.C. boards
Zero cross detecting
12 times
circuit
Nonvolatile memory
14 times data (outdoor power P.C.
board )
IPM protection
Overcurrent
Discharge temperature
protection
Fin temperature
protection
P.C. board temperature
protection
High-pressure
protection
Out-of-step protection
Bus-bar voltage
protection
Zero cross loss
Low out side
temperature protection
(cooling)
Primary current
protection
Outdoor fan motor
Condition
The indoor unit detects an 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 outdoor power P.C.
board for more than 10 seconds.
The protection cut-out of the zero cross detecting
circuit operates 3 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 237.2°F during
operation. Compressor can restart if discharge
temperature thermistor reads 212°F or less 3
minutes later.
The fi n temperature exceeds 230°F during
operation.
The P.C. board temperature exceeds 203°F during
operation.
High-pressure is detected with the high-pressure
switch (HPS) during operation.
The outdoor heat exchanger temperature
exceeds 158°F during cooling or indoor gas pipe
temperature exceeds 158°F during heating.
The waveform of compressor current is distorted.
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 10.4°F 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 68°F or more.
63
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 outdoor power P.C. board .
• Replace the outdoor power P.C. board .
• Refer to 11-6. "Check of outdoor
thermistors".
• Replace the outdoor control P.C. board.
• Replace the outdoor power P.C. board.
• Check the connecting wire between outdoor
control P.C. board and outdoor power P.C. board.
• Check the connecting wire between outdoor
control P.C. board and outdoor power P.C. board.
• Replace theoutdoor power P.C. 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.
• Reconnect connector of compressor.
• Refer to 11-6. "How to check inverter/
compressor".
• Check the voltage of power supply.
• Replace the outdoor power P.C. 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".