Mitsubishi Electric M Series Manual page 168

WALL-MOUNTED Inverter Heat Pump
MUZ-FD50VA
MUZ-FD50VAH
Troubleshooting check table
Indication
Symptom
No.
LED1(Red) LED2(Yellow)
Outdoor unit
does not
operate.
1
Lightning Twice
Lightning 3 times
2
Lightning 4 times
3
4
Lightning 5 times
5 Lightning 6 times
6
Lightning 7 times
7
Lightning 8 times
Lightning 11 times
8
9
Lightning 12 times
'Outdoor unit
stops and
restarts 3
minutes
Twice Goes out
10
later' is
repeated.
3 times Goes out
11
12 4 times Goes out
5 times Goes out
13
14
8 times Goes out
15 9 times Goes out
16 13 times Goes out
17 Lighting 8 times
18 Lighting 11 times
Lighting 12 times
19
NOTE 1. The location of LED is illustrated at the right figure.
2. LED is lighted during normal operation.
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
2.5-second OFF
OFF
C-166
Abnormal point/Condition
Overcurrent protection stop is continuously performed
3 times within 1 minute after the compressor gets
started, or when converter protection stop or bus-bar
Outdoor power system
voltage protection stop is continuously performed 3
times within 3 minutes after start-up.
A short circuit is detected in the thermistor during
Discharge temperature
operation, or an open circuit is detected in the
thermistor
thermistor after 10 minutes of compressor 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
thermistor during operation.
A short circuit is detected in the thermistor during operation,
Outdoor heat exchanger
or an open circuit is detected in the thermistor after 5 minutes
temperature thermistor
(in cooling) and 10 minutes (in heating) of compressor start-up.
A short circuit is detected in the thermistor during operation,
or an open circuit is detected in the thermistor after 5 minutes
Defrost thermistor
of compressor start-up.
The communication fails between the indoor and outdoor
Serial signal
unit for 3 minutes.
Nonvolatile memory data The nonvolatile memory data cannot be read properly.
Current sensor Current sensor protection stop is continuously performed twice.
The communication protection stop between boards is
Communication error
continuously performed twice.
between P.C. boards
The protection stop of the zero cross detecting circuit is
Zero cross detecting
continuously performed 10 times.
circuit
Overcurrent is detected after 30 minutes of compressor start-up.
IPM protection
Overcurrent is detected within 30 minutes of compressor
Lock protection
start-up.
Discharge temperature Discharge temperature exceeds 116 during operation and
protection
compressor stops. Compressor can restart if discharge
temperature thermistor reads 100
Fin temperature
The fin temperature exceeds 87
protection
P.C. board temperature
The P.C. board temperature exceeds 70
protection
The outdoor heat exchanger temperature exceeds 70
High-pressure
cooling or indoor gas pipe temperature exceeds 70
protection
heating.
Converter protection A failure is detected in the operation of the converter during
operation.
Bus-bar voltage The bus-bar voltage exceeds 400V or falls to 200V or below
protection (1) during compressor operating.
Bus-bar voltage The bus-bar voltage exceeds 400V or falls to 50V or below
protection (2) during compressor operating.
Failure occurs continuously 3 times within 30 seconds after the
Outdoor fan motor
fan gets started.
Current sensor A short or open circuit is detected in the current sensor during
protection compressor operating.
Communication error occurs between the outdoor electronic
Communication between P.C.
control P.C. board and power board for more than 10 seconds.
boards protection
Zero cross signal cannot be detected while the compressor is
Zero cross detecting circuit
operating.
protection
0.5-second ON
2.5-second OFF
Condition
or less 3 minutes later.
during operation.
during operation.
during
during
Outdoor electronic control P.C. board(Parts side)
Lighting
0.5-second ON
M series
LED2 LED1