48
MXZ-3HA
No.
Symptom
Indication
Abnormal point / Con-
dition
Condition
Remedy
LED1(Red) LED2(Yellow)
1
Outdoor
unit does
not operate.
Lit
Once
LEV and drain pump
The indoor unit detects an abnormality in the LEV
and drain pump.
• Refer to 12-6. "Check of LEV".
• Check the drain pump of the indoor unit.
2
Lit
Twice
Outdoor power
system
Overcurrent protection cut-out operates 3 consecu-
tive times within 1 minute after the compressor
gets started, or converter protection cut-out or bus-
bar voltage protection cut-out operates 3 consecu-
tive times within 3 minutes after startup.
• Check the connection of the compressor connect-
ing wire.
• Refer to 12-6. "How to check inverter/compres-
sor".
• Check the stop valve.
3
Lit
3 times
Discharge temperature
thermistor
A short circuit is detected in the thermistor during
operation, or an open circuit is detected in the ther-
mistor after 10 minutes of compressor startup.
• Refer to 12-6. "Check of outdoor thermistors".
4
Lit
4 times
Fin temperature
thermistor
A short or open circuit is detected in the thermistor
during operation.
• Refer to 12-6. "Check of outdoor thermistors".
P. C. board tempera-
ture thermistor
• Replace the outdoor control P.C. board.
5
Lit
5 times
Ambient temperature
thermistor
A short or open circuit is detected in the thermistor
during operation.
• Refer to 12-6. "Check of outdoor thermistors".
Outdoor heat ex-
changer temperature
thermistor
A short circuit is detected in the thermistor during
operation, or an open circuit is detected in the ther-
mistor after 5 minutes (in cooling) and 10 minutes
(in heating) of compressor startup.
Defrost thermistor
A short circuit is detected in the thermistor during
operation, or an open circuit is detected in the ther-
mistor after 5 minutes of compressor startup.
6
Lit
6 times
Zero cross detecting
circuit (Outdoor control
P.C. board)
Zero cross signal cannot be detected.
• Replace the outdoor control P.C. board.
7
Lit
7 times
Outdoor control system
The nonvolatile memory data cannot be read
properly.
• Replace the outdoor control P.C. board.
8
Lit
8 times
Current sensor
Current sensor protection cut-out operates 2 con-
secutive times.
• Replace the outdoor power P.C. board.
9
Lit
11 times
Communication error
between P.C. boards
The communication protection cut-out between
boards operates 2 consecutive times.
• Check the connecting wire between outdoor con-
trol P.C. board and outdoor power P.C. board.
M-NET communication
error
M-NET adapter P.C. board detects an abnormality
in the communication error.
• Check the connecting wire between M-NET
adapter P.C. board and outdoor control P.C.
board, or terminal block.
10
Lit
12 times
Zero cross detecting
circuit (Outdoor power
P.C. board)
The protection cut-out of the zero cross detecting
circuit operates 10 consecutive times.
• Replace the outdoor power P.C. board.
11
Lit
13 times
Current sensor
A short or open circuit is detected in the input cur-
rent detection circuit during operation.
• Replace the outdoor power P.C. board.
12
Lit
14 times
Voltage sensor
A short or open circuit is detected in the input volt-
age detection circuit during operation.
• Replace the outdoor power P.C. board.
13
Lit
15 times
Relay operation
No relay operation is detected during operation.
• Replace the outdoor power P.C. board.
14 'Outdoor unit
stops and
restarts
3 minutes
later' is
repeated.
Twice
Not lit
IPM protection
Overcurrent is detected after 30 seconds of com-
pressor startup.
• Reconnect compressor connector.
• Refer to 12-6. "How to check inverter/
compressor".
• Check the stop valve.
• Check the power module (PAM module).
Lock protection
Overcurrent is detected within 30 seconds of com-
pressor startup.
15
3 times
Not lit
Discharge temperature
protection
The discharge temperature exceeds 115°C during
operation.
Compressor can restart if discharge temperature
thermistor reads 80°C or less 3 minutes later.
• Check the amount of gas and refrigerant circuit.
• Refer to 12-6. "Check of LEV".
16
4 times
Not lit
Fin temperature
protection
The fin temperature exceeds during operation.
•Check refrigerant circuit and refrigerant amount.
•Refer to 12-6. "Check of outdoor fan motor".
P.C. board temperature
protection
The P.C. board temperature exceeds during opera-
tion.
17
5 times
Not lit
High pressure
protection
High pressure is detected with the high pressure
switch (HPS) during operation.
• Check around of gas and the refrigerant circuit.
• Check the stop valve.
The outdoor heat exchanger temperature exceeds
70°C during cooling or the indoor gas pipe tem-
perature exceeds 70°C during heating.
18
6 times
Not lit
Pre-heating protection
Overcurrent is detected during pre-heating.
• Reconnect compressor connector.
• Refer to 12-6. "How to check inverter/
compressor".
• Check the power module.
19
8 times
Not lit
Converter protection
A failure is detected in the operation of the convert-
er during operation.
• Replace the outdoor power P.C. board.
20
9 times
Not lit
Bus-bar voltage
protection
The bus-bar voltage exceeds 400 V or falls to low
level during compressor operating.
• Check the voltage of power supply.
• Replace the outdoor power P.C. board or the out-
door control P.C. board.
• Refer to 12-6. "Check of bus-bar voltage".
21
11 times
Not lit
Low outside tempera-
ture protection(cooling)
The ambient became -12°C or less.
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OBH828A
