Mitsubishi Electric MXZ-2E53VAHZ, Service Manual

Page: 81 / 328

81
11-4. TROUBLESHOOTING CHECK TABLE
No. Symptom
Indication
Abnormal point / Con-
dition
Condition Remedy
LED1(Red) LED2(Yellow)
1 Outdoor
unit does
not operate.
Lighted Once LEV and drain pump
The indoor unit detects an abnormality in the LEV
and drain pump. • Refer to 11-6. "Check of LEV".
• Check the drain pump of the indoor unit.
2
Lighted 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 start-up. • Check the connection of the compressor connect-
ing wire.
• Refer to 11-6. "How to check inverter/compres-
sor".
• Check the stop valve.
3
Lighted 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 start-up.
• Refer to 11-6. "Check of outdoor thermistors".
4
Lighted 4 times
Fin temperature
thermistor
A short or open circuit is detected in the thermistor
during operation.
• Refer to 11-6. "Check of outdoor thermistors".
P. C. board tempera-
ture thermistor
• Replace the outdoor control P.C. board.
5
Lighted 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 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 start-up.
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 start-up.
6
Lighted 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
Lighted 7 times Outdoor control system
The nonvolatile memory data cannot be read
properly.
• Replace the outdoor control P.C. board.
8
Lighted 8 times Current sensor
Current sensor protection cut-out operates 2 con-
secutive times.
• Replace the outdoor power P.C. board.
9
Lighted 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
Lighted 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
Lighted 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
Lighted 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 Lighted 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 lighted
IPM protection
Overcurrent is detected after 30 seconds of com-
pressor start-up.
• Reconnect compressor connector.
• Refer to 11-6. "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 start-up.
15
3 times Not lighted
Discharge temperature
protection
The discharge temperature exceeds 115°C (
MXZ-
3E54/3E68/4E72VA
)/ 106°C(
MXZ-4E83/5E102VA,
MXZ-2E52VAHZ
)/ 116°C (
MXZ-4E83VAHZ
) during
operation.
Compressor can restart if discharge temperature
thermistor reads 80°C (
MXZ-3E54/3E68/4E72VA
)/
95°C (
MXZ-4E83/5E102VA, MXZ-2E52VAHZ
)/
100°C (
MXZ-4E83VAHZ
) or less 3 minutes later.
• Check the amount of gas and refrigerant circuit.
• Refer to 11-6. "Check of LEV".
16
4 times Not lighted
Fin temperature
protection
The fi n temperature exceeds during operation.
•Check refrigerant circuit and refrigerant amount.
•Refer to 11-6. "Check of outdoor fan motor".
P.C. board temperature
protection The P.C. board temperature exceeds during opera-
tion.
17
5 times Not lighted
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 lighted Pre-heating protection Overcurrent is detected during pre-heating.
• Reconnect compressor connector.
• Refer to 11-6. "How to check inverter/
compressor".
• Check the power module.
19
8 times Not lighted 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 lighted
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 11-6. "Check of bus-bar voltage".
21
11 times Not lighted
Low outside tempera-
ture protection(cooling)
The ambient became -12°C or less. —
OBH723C