Troubleshooting Flow - Mitsubishi Electric MFZ-KA25VA Service Manual

10-6. Troubleshooting flow

When the left lamp of OPERATION INDICATOR lamp flashes 3 times and the right lamp of OPERATION INDICATOR
lamp is not lighted.
Indoor fan does not operate.
-1. Check of indoor fan motor (upper)
A
The indoor fan motor error has occurred, and the indoor fan doesn't operate.
Turn OFF the power supply.
Is there anything that interferes the
rotation of the line flow fan?
Yes
Remove the object and
adjust the line flow fan.
Is there 311V DC between
CN211 1 (+) and 3 (-), and does
the voltage between CN211 5(+)
and 3(-) rise to the range between 3
and 6V DC within 12 seconds after
EMERGENCY OPERATION switch
is pressed?
Replace the indoor electronic control P.C. board.
The indoor fan motor error has occurred, and the indoor fan repeats "12-second ON and 30-second OFF" 3 times, and then stops.
Measure the voltage between CN211
6(+) and 3(-) while the fan
motor is rotating.
Pay careful attention to the high voltage on
the fan motor connector CN211.
Turn ON the power supply, wait 5 seconds or more, and then press
EMERGENCY OPERATION switch.
Measure the supply voltage as follows within 12 seconds
No
after EMERGENCY OPERATION switch is pressed.
If more than 12 seconds passes by, turn OFF the power supply and
turn ON it again, then measure the voltage. w
1) Measure the voltage between CN211 1(+) and 3(-).
2) Measure the voltage between CN211 5(+) and 3(-).
wIf more than 12 seconds passes after EMERGENCY OPERATION switch
is pressed, the voltage mentioned in above 2) goes 0V DC although the
indoor electronic control P.C. board is normal.
Yes
Replace the indoor fan motor.
No
Is 0V DC or 15V DC
held unchanged?
Replace the indoor fan motor.
Fuse (F11)
VARISTOR (NR11)
R111
No
(Changed)
Replace the indoor electronic control P.C. board.
Yes
(Unchanged)
27
Indoor electronic
control P.C. Board
JR06
JR05
IC101
CN1X1 CN1Y1
CN151
T11
C111
CN152
CN211
CN212