MXZ-5C42NA3 Service Manual

115
12-4. TROUBLESHOOTING CHECK TABLE
No. Symptom
Indication
Abnormal point /
Condition
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 consec-
utive times within 1 minute after the compressor
gets started, or converter protection cut-out or
bus-bar voltage protection cut-out operates 3 con-
secutive times within 3 minutes after startup.
• Check the connection of the compressor
connecting wire.
• Refer to 12-6.
"How to check inverter/
compressor".
• 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
thermistor 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
exchanger temperature
thermistor
A short circuit is detected in the thermistor during
operation, or an open circuit is detected in the
thermistor 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
thermistor 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
consecutive 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 bed.
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
Lit 21 times 4-way valve
Connector of R.V. coil is disconnected, poorly con-
nected or 4-way valve is faulty.
• Refer to 12-6.
"Check of R.V. coil".
• Check the 4-way valve.
15 '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
compressor startup.
16
3 times Not lit
Discharge temperature
protection
The discharge temperature exceeds 239°F (MXZ-
2C20NA2, MXZ-2C20NA3, MXZ-2C20NA4)/
222.8°F (MXZ-3C24/3C30/4C36NA, MXZ-3C24/
3C30/4C36NA2, MXZ-3C24/3C30/4C36NA3, MXZ-
3C24/3C30/4C36NA4)/240.8°F (MXZ-2C20/3C24/
3C30NAHZ, MXZ-5C42NA, MXZ-2C20/3C24/
3C30NAHZ2, MXZ-5C42NA2, MXZ-2C20/3C24/
3C30NAHZ3, MXZ-5C42NA3, MXZ-2C20/3C24/
3C30NAHZ4, MXZ-5C42NA4) during operation.
Compressor can restart if discharge temperature
thermistor reads 176°F (MXZ-2C20NA2, MXZ-
2C20NA3, MXZ-2C20NA4)/203°F (MXZ-3C24/
3C30/4C36NA, MXZ-3C24/3C30/4C36NA2, MXZ-
3C24/3C30/4C36NA3, MXZ-3C24/3C30/
4C36NA4)/212°F (MXZ-2C20/3C24/3C30NAHZ,
MXZ-5C42NA, MXZ-2C20/3C24/3C30NAHZ2,
MXZ-5C42NA2, MXZ-2C20/3C24/3C30NAHZ3,
MXZ-5C42NA3, MXZ-2C20/3C24/3C30NAHZ4,
MXZ-5C42NA4) or less 3 minutes later.
• Check the amount of gas and refrigerant circuit.
• Refer to 12-6.
"Check of LEV".
17
4 times Not lit
Fin temperature
protection
The n 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
operation.
OBH702M