Mitsubishi Electric MSZ-A09RV-E1 Service Manual page 42

1. Troubleshooting check table
MSZ-A09RV -
E1
MSZ-A12RV -
E1
· 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.
No.
Symptom Operation indicator lamp
Outdoor unit repeated flashes
does not every 0.5 seconds
operate
1
One flash
w2
2.5 seconds OFF
2 flashes
2.5 seconds OFF
w3
3 flashes
w4
2.5 seconds OFF
5 flashes
2.5 seconds OFF
5
6 flashes
2.5 seconds OFF
6
7 flashes
2.5 seconds OFF
7
12 flashes
2.5 seconds OFF
8
wWhen the indoor unit has started operation and the above detection method has detected an abnormality (the first detection
after the power ON), the 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 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.
(Indoor unit troubleshooting check table)
Abnormal point
Mis-Wiring When indoor electronic control p.c. board does not
receive serial signals for 4 to 5 seconds with
OPERATION/STOP button of remote controller ON
and 52C relay 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.
Serial signal
When indoor electronic control p.c. board does not
receive serial signals from outdoor unit for 4 to 5
seconds,
Indoor coil
Indoor electronic control p.c. board constantly
thermistor
detects resistance every 8 seconds.
Auxiliary indoor
When thermistor shorts or opens.
coil thermistor
Room
temperature
thermistor
When rotational frequency feedback signal is not
Indoor fan motor.
emit during 12-second indoor fan operation.
Outdoor power When compressor has stopped due to over current
system protection or start-up failure protection 3 times in a
row within 1 min. after start-up.
<Thermistor short>
Outdoor
thermistors 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 min. after compressor start-up.
When nonvolatile memory data cannot be read properly
Outdoor control
on outdoor control P.C. board, outdoor unit stops and
system
restarts 3 minutes later,
When the converter protective suspension within 1
Converter power
minute after start-up of the converter is operated 5
system
times successively.
Also bus-bar voltage malfunction (140V or less or 400V
or more) within 1 minute after start-up of the converter
has happened 5 times successively.
42
POWER
flash
Detection method Checkpoint
Refer to 'Checking
serial signal error' on
page 44.
Refer to the
characteristics of
indoor coil thermistor,
auxiliary indoor coil
thermistor, and room
temperature.
thermistor on page
Refer to F "Check of
indoor fan motor" on
page 49.
Refer to "How to
check
inverter/compressor"
on page 47.
· Shortage of
refrigerant
· Outdoor electronic
control p.c. board
Refer to I "Check
of outdoor
thermistors" on
page 50.
Replace outdoor
electronic control P.C.
board.
Refer to I "Check of
inverter P.C.board" on
page 50.