Troubleshooting Check Table - Mitsubishi Electric MSZ-G09SV Service Manual

1. Troubleshooting check table

INDOOR UNIT
MSZ-G09SV - MSZ-G12SV -
E1
MSZ-G09SV - MSZ-G12SV -
E2
•The following indication applies regardless of shape of the indicator.
flashing
Operation Indicator
NOTE: Before taking measures, make sure that the symptom reappears, for accurate troubleshooting.
Self check table
Abnormal
No. Operation indicator lamp
point
0.5-second ON
Mis-Wiring
1
0.5-second OFF
1-time flash
Serial
W2
signal
2.5-second OFF
Indoor coil
2-time flash
thermistor
W3
Room
2.5-second OFF
tempera-
ture
thermistor
3-time flash
Indoor fan
W4
motor
2.5-second OFF
5-time flash
Outdoor
5
power
system
6-time flash
Outdoor
6
thermistors
7-time flash
Outdoor
7 control
system
NOTE : w When the indoor unit has started operation and the above detection method has detected an abnormality (the first
detection after the power ON), the indoor electronic control P.C. board turns OFF the 52C and the indoor fan motor
with the OPERATION INDICATOR lamp lighting.
When the 52C and the indoor fan motor are turned ON again 3 minutes later and the same abnormality is detected
(a second detection of the above abnormality after the power ON), the indoor electronic control P.C. board turns
OFF the 52C and the indoor fan motor with the OPERATION INDICATOR lamp flashing.
However, the first detection is cleared in case the power is turned OFF after the first detection.
E1
E2
· Flashing of the OPERATION INDICATOR lamp (on the left-hand side) indicates possible
abnormalities.
· The OPERATION INDICATOR lamp (on the left-hand side) is lighting during normal operation.
Symptom
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
2.5-second OFF
Outdoor unit
does not
operate.
2.5-second OFF
Outdoor unit
does not
operate.
2.5-second OFF
Detection method
When indoor electronic control P.C. board
does not receive serial signals for 4 to 5
seconds with OPERATION/ STOP(ON/ OFF)
button of remote controller ON and 52C
contactor ON for the first time.
NOTE: In case of serial signal error, mis-wiring
indication will appear by turning power
off and then turning it back on.
When indoor electronic control P.C. board
does not receive serial signals from outdoor
unit for 4 to 5 seconds,
Detect Indoor coil/room temperature
thermistor short or open circuit every 8
seconds during operation.
When rotational frequency feedback signal is
not emit during 12-second indoor fan
operation.
When compressor has stopped due to over
current protection or start-up failure protection
3 times in a row within 1 minute after start-up.
<Thermistor short>
Thermistors are abnormal when they short
after compressor start-up.
<Thermistor open>
Thermistors are abnormal when they open
after compressor start-up.
However, discharge temperature thermistor is
abnormal when open circuit is detected more
than 10 minutes after compressor start-up.
When it cannot properly read data in the
nonvolatile memory of outdoor electronic
control P.C. board.
69
Checkpoint
• Refer to Q "How to check
mis-wiring and serial signal
error" on page 83.
• Refer to the characteristics of
indoor coil thermistor,
sub indoor coil
thermistor, and room
temperature thermistor on
page 90.
• Refer to G "Check of
indoor fan motor" on page 78.
• Refer to A "How to check
inverter/ compressor" on page
76.
• Shortage of refrigerant
• Replace the outdoor control
P.C. board.
Refer to J "Check of outdoor
thermistors" on page 79.
• Replace the outdoor
electronic control P.C. board.