Troubleshooting - Mitsubishi Electric MU-A09WA Service Manual

8

TROUBLESHOOTING

MU-A09WA MU-A12WA
8-1. Cautions on troubleshooting
1. Before troubleshooting, check the following:
1) Check the power supply voltage.
2) Check the indoor/outdoor connecting wire for mis-wiring.
2. Take care the following during servicing.
1).Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and then after
confirming the horizontal vane is closed, turn OFF the breaker and / or disconnect the power plug.
2) Be sure to turn OFF the power supply before removing the front panel,
the cabinet, the top panel and the electronic control P.C. board.
3) When removing the electronic control P.C. board, hold the edge of the
board with care NOT to apply stress on the components.
4) When connecting or disconnecting the connectors, hold the housing of the
connector. DO NOT pull the lead wires.
8-2. Instruction of trouble shooting
If indoor unit and outdoor unit doesn't operate, please check of outdoor unit fuse F.
8-3.Trouble criterion of main parts
MU-A09WA
MU-A12WA
Part name
Compressor (MC)
Measure the resistance between the terminals with a tester.
INNER
(Coil wiring temperature 14°F ~ 104°F)
PROTECTOR
MU-A09WA
Color of the
302 i 9°F OPEN
194 i18°F CLOSE
MU-A12WA
338 i 9°F OPEN
194 i18°F CLOSE
MU-A12WA-
1
311i 9°F OPEN
194 i18°F CLOSE
Outdoor fan
motor (MF)
INNER
Measure the resistance between the terminals with a tester.
PROTECTOR
(Coil wiring temperature 14°F ~ 104°F)
MU-A09WA
248 i 9°F OPEN
Color of the
INNER
WHT-BLK
PROTECTOR
BLK-RED
MU-A12WA
248 i 9°F OPEN
Check method and criterion
lead wire
MU-A09WA
C-R
0.71~0.87"
C-S 1.31~1.61"
lead wire
MU-A09WA
51~63"
62~76"
Lead wiring
Normal
MU-A12WA
0.58~0.71"
1.09~1.33"
Normal
MU-A12WA
27~33"
34~41"
16
Housing point
Figure
WHT
C
P
S R
BLK
RED
MU-A09WA
MAIN
AUX.
Fuse
BLK
RED WHT
MU-A12WA
MAIN
AUX.
BLK RED ORN WHT
P P :INNER PROTECTOR