Mitsubishi Electric MSZ-LN-VG Series Service Manual page 105

MXZ-3F, 4F
Indication
No. Symptom
LED1(Red) LED2(Yellow)
1 Outdoor
Lit
unit does
not operate.
2
Lit
3
Lit
4
Lit
5
Lit
6
Lit
7
Lit
8
Lit
9
Lit
10
Lit
11
Lit
12
Lit
13 Lit
14
Lit
15
Lit
16
Lit
17 'Outdoor unit
stops and
restarts
Twice
3 minutes
later' is
repeated.
18
3 times
19
4 times
20
5 times
OBH790D
Abnormal point / Con-
dition
Once LEV and drain pump
Outdoor power
Twice
system
Discharge temperature
3 times
thermistor
Fin temperature
thermistor
4 times
P. C. board tempera-
ture thermistor
Ambient temperature
thermistor
Outdoor heat ex-
changer temperature
5 times
thermistor
Defrost thermistor
Zero cross detecting
6 times circuit (Outdoor control
P.C. board)
7 times Outdoor control system
8 times Current sensor
Communication error
between P.C. boards
11 times
M-NET communication
error
Zero cross detecting
12 times circuit (Outdoor power
P.C. board)
13 times Current sensor
14 times Voltage sensor
15 times Relay operation
Detection of refrigerant
18 times
(Indoor unit)
Abnormality of refriger-
19 times ant leakage sensor
(Indoor unit)
Incompatible unit com-
20 times
bination error
IPM protection
Not lit
Lock protection
Discharge temperature
Not lit
protection
Fin temperature
protection
Not lit
P.C. board temperature
protection
High pressure
Not lit
protection
Condition
The indoor unit detects an abnormality in the LEV
and drain pump.
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.
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.
A short or open circuit is detected in the thermistor
during operation.
A short or open circuit is detected in the thermistor
during operation.
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.
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.
Zero cross signal cannot be detected.
The nonvolatile memory data cannot be read
properly.
Current sensor protection cut-out operates 2 con-
secutive times.
The communication protection cut-out between
boards operates 2 consecutive times.
M-NET adapter P.C. board detects an abnormality
in the communication error.
The protection cut-out of the zero cross detecting
circuit operates 10 consecutive times.
A short or open circuit is detected in the input cur-
rent detection circuit during operation.
A short or open circuit is detected in the input volt-
age detection circuit during operation.
No relay operation is detected during operation.
1. Refrigerant leaks from the piping or the
heat exchanger in the indoor unit.
2. The following items are used around the
indoor unit.
• Spray (LP gas including Freon, and whose
main ingredient is propane and butane)
• Aerosol insecticide (including ethanol)
• Air spray painting (including dichlorometh-
ane)
• Charcoal (charcoal fire)
• Chemicals (such as ethanol)
The refrigerant sensor mounted on the indoor
unit does not work.
The refrigerant sensor is not connected prop-
erly or the wire is broken.
The indoor unit which is not compatible with
the outdoor unit is connected.
Overcurrent is detected after 30 seconds of com-
pressor startup.
Overcurrent is detected within 30 seconds of com-
pressor startup.
The discharge temperature exceeds 115°C during
operation.
Compressor can restart if discharge temperature
thermistor reads 80°C or less 3 minutes later.
The fin temperature exceeds during operation.
The P.C. board temperature exceeds during opera-
tion.
High pressure is detected with the high pressure
switch (HPS) during operation.
The outdoor heat exchanger temperature exceeds
70°C during cooling or the indoor gas pipe tem-
perature exceeds 70°C during heating.
105
Remedy
• Refer to 12-6. "Check of LEV".
• Check the drain pump of the indoor unit.
• Check the connection of the compressor connect-
ing wire.
• Refer to 12-6. "How to check inverter/compres-
sor".
• Check the stop valve.
• Refer to 12-6. "Check of outdoor thermistors".
• Refer to 12-6. "Check of outdoor thermistors".
• Replace the outdoor control P.C. board.
• Refer to 12-6. "Check of outdoor thermistors".
• Replace the outdoor control P.C. board.
• Replace the outdoor control P.C. board.
• Replace the outdoor power P.C. board.
• Check the connecting wire between outdoor con-
trol P.C. board and outdoor power P.C. board.
• Check the connecting wire between M-NET
adapter P.C. board and outdoor control P.C.
board, or terminal block.
• Replace the outdoor power P.C. board.
• Replace the outdoor power P.C. board.
• Replace the outdoor power P.C. board.
• Replace the outdoor power P.C. board.
• Turn off the power after the indoor unit fin-
ishes its fan operation.
(The fan operation continues for 3 hours.)
• Check the indoor unit to detect the part
where refrigerant leaks.
• Repair the part where refrigerant leaks.
• Turn on the power again.
• Replace the refrigerant sensor if the problem
is not fixed.
• Connect the connector of the refrigerant sen-
sor properly.
• Replace the refrigerant sensor.
• Replace the indoor unit with the one which is
compatible with the outdoor unit.
• Reconnect compressor connector.
• Refer to 12-6. "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 12-6. "Check of LEV".
•Check refrigerant circuit and refrigerant amount.
•Refer to 12-6. "Check of outdoor fan motor".
• Check around of gas and the refrigerant circuit.
• Check the stop valve.