Microprocessor Control; Troubleshooting - Mitsubishi Electric MSC-07RV-E2 Service Manual

6

MICROPROCESSOR CONTROL

MSC-07RV - MSC-07RV -
E4
MSC-09RV - MSC-09RV -
E4
MSC-12RV - MSC-12RV -
E4
11-1. COOL ( ) OPERATION
6-1.
1. Indoor fan speed control
Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button regard-
less of thermostat's OFF-ON.
In Auto the fan speed is as follows.
MSC-07RV - MSC-07RV -
E1
MSC-09RV - MSC-09RV -
E1
MSC-12RV - MSC-12RV -
E1
Room temperature minus set temperature : 2 degrees or more································High
Room temperature minus set temperature : Between 1 and 2 degrees····················Med.
Room temperature minus set temperature : less than 1 degree································Low
MSC-07RV - MSC-07RV -
E4
MSC-09RV - MSC-09RV -
E4
MSC-12RV - MSC-12RV -
E4
Room temperature minus set temperature : 1.7 degrees or more·····························High
Room temperature minus set temperature : Between 1 and 1.7 degrees·················Med.
Room temperature minus set temperature : less than 1 degree································Low
7

TROUBLESHOOTING

7-1.
Trouble criterion of main parts
MSC-07RV - MSC-07RV -
E4
MSC-09RV - MSC-09RV -
E4
MSC-12RV - MSC-12RV -
E4
Part name
Measure the resistance between the terminals with a tester.
(Coil wiring temperature10°C ~ 30°C)
Indoor fan
motor(MF)
INNER FUSE
136I3 CUT OFF
Measure the resistance between the terminals with a tester.
(Coil wiring temperature –10°C ~ 40°C)
Color of
lead wire
Outdoor fan
motor(MF)
WHT-BLK
BLK-RED
INNER FUSE
163I3 CUT OFF
Color of
lead wire
WHT-BLK
BLK-RED
MU-07RV -
E5
MU-09RV -
E5
MU-12RV -
E5
MSC-07RV -
E2 E3
MSC-09RV -
E2 E3
MSC-12RV -
E2 E3
Initial temperature difference
E5
E5
E5
Initial temperature difference
MU-07RV -
E5
MU-09RV -
E5
MU-12RV -
E5
Check method and criterion
Color of
lead wire
MSC-07/09RV-
E4
396 ~ 430Ω
WHT-BLK
BLK-RED 320 ~ 348Ω
Normal
MU-07/09RV-
E4
311 ~ 381 Ω
283 ~ 347Ω
Normal
MUH-07/09RV-
E4
311 ~ 381 Ω
283 ~ 347 Ω
MUH-07RV -
E4 E4
MUH-09RV -
E4 E4
MUH-12RV -
E4 E4
MUH-07RV -
E4
E4
MUH-09RV -
E4
E4
MUH-12RV -
E4
E4
Normal
MSC-12RV-
E5 E4 E5
396 ~ 430Ω
320 ~ 348Ω
Abnormal
MU-12RV-
E4
265 ~ 325Ω
Open or short-circuit
292 ~ 359Ω
Abnormal
MUH-12RV-
E4
265 ~ 325Ω
Open or short-circuit
292 ~ 359 Ω
16
Difference between room
temperature and set tem-
Fan speed
perature during operation
1 deg. 1.7 deg.
Difference between room
temperature and set tem-
Fan speed
perature during operation
1 deg. 1.7 deg.
Abnormal
Open or
short-circuit
BLK
2 deg. 4 deg.
3 deg.
Figure
WHT
RED
BLK
FUSE
YLW
GRY
BRN
MAIN
AUX.
FUSE
RED WHT