Troubleshooting Check Table; Normal Operation - Mitsubishi Electric MSH-18RV Service Manual

1. Troubleshooting check table

MSH-18RV
• The following indication does not depend on the shape of lamp.
flashing
· Flashing of the OPERATION INDICATOR lamp (on the left-hand side)
Operation Indicator
indicates possible abnormalities.
· The OPERATION INDICATOR lamp (on the left-hand side) is lighting during

normal operation.

Before taking measures, make sure that the symptom reappears, for accurate troubleshooting.
Self check table
Abnormal
NO.
point
0.5-second ON
Mis-wiring
0.5-second OFF
1
1-time flash
Serial sig-
nal
2.5-second OFF
Indoor coil
2-time flash
thermistor
2
Room
tempera-
ture ther- 2.5-second OFF
mistor
3-time flash
Indoor fan
3
motor
2.5-second OFF
6-time flash
Defrost
4
thermistor
5-time flash
Outdoor
5
power
system
7-time flash
Outdoor
6
control
P.C. board
Outdoor
10-time flash
refrigerant
system
7
error
MXZ-32NV
MXZ-32RV
only
Operation Indicator
Outdoor
8
control
lighted
P.C. board
flashing
The indication is shown only when the indoor unit connects with the outdoor unit MXZ-32NV-
Indication
Outdoor unit
does not run.
Outdoor unit
does not run.
Indoor fan motor
repeats 12 sec-
onds ON and 3
minutes OFF.
When the indoor
fan breaks, the
fan motor keeps
stopping.
Outdoor unit
does not run
2.5-second OFF
Outdoor unit
does not run
2.5-second OFF
Outdoor unit
does not run
2.5-second OFF
Outdoor unit
does not run
2.5-second OFF
Outdoor unit
runs but the
indoor unit does
2.5-second OFF
not run.
Symptom Detect method
When serial signal stops for 4
to 5 seconds after 1st on of
52C relay by POWER turning
on.
When serial signal from out-
door unit stops for 4 to 5 sec-
onds.
Detect Indoor coil/room tem-
perature 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 the defrost thermistor
shorts or opens after the com-
pressor start-up.
When the compressor opera-
tion is continuously three times
interrupted by over current
protection within 1 minute after
start-up , it stops operation.
When it cannot properly read
data in the nonvolatile memory
of the outdoor control
P.C.board.
When the compressor opera-
tion has been interrupted by
LEV protection continuously 5
minutes, the compressor stops
operation.
When the operation mode of
each indoor unit is differently
set to COOL(includes DRY)
and HEAT at same time, the
operation mode of indoor unit
that has operated at first has
the priority.
E1 E2
, , MXZ-32RV-
55
Check point
Check wiring (visual check and conductiv-
ity check).
Check indoor electronic control
P.C.board.
Check outdoor DEICER P.C. board.
Check electrical parts.
Check resistance of thermistor.
Re-connect connector.
Check indoor electronic control P.C.board.
Disconnect connector CN211 and then
check connector CN121 - to make
2
3
sure rotational frequency feedback signal
of 1.5V or over exists.
Check indoor electronic control P.C.
board.
Check indoor fan motor.
Re-connect connector.
Check outdoor DEICER P.C. board.
Check resistance of thermistor.
Re-connect connector.
Check the inverter output.
Check the compressor.
Check the outdoor control P.C.board.
Amount of gas.
Check the outdoor control P.C. board.
Contact of LEV board connectors.
Unify the operation mode.
E1 E1
and MXZ-32SV-