Troubleshooting Flow - Mitsubishi Electric MSZ-FD25VA Service Manual

10-6. TROUBLESHOOTING FLOW

A Check of indoor fan motor
The indoor fan motor error has occurred, and the indoor fan does not operate.
Turn OFF the power supply.
Is there any foreign matter that interferes
the rotation of the line fl ow fan?
Yes
Remove the foreign matter and
adjust the line fl ow fan.
Is there 325 VDC between CN211
(+) and (-), and does the voltage
between CN211
to the range of 3 to 6 VDC within 12
seconds after EMERGENCY OPERA-
TION 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
(+) and (-) while the fan motor is
rotating.
Pay enough 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 after EMER-
GENCY OPERATION switch is pressed.
No If more than 12 seconds passes, turn OFF the power supply and turn it
ON again, then measure the voltage.
1. Measure the voltage between CN211
2. Measure the voltage between CN211
If more than 12 seconds passes after EMERGENCY OPERATION switch
is pressed, the voltage measured at 2. above goes 0 VDC although the
indoor electronic control P.C. board is normal
(+) and (-) rise
Yes
No
Is it unchanged holding
0 or 15 VDC?
Replace the indoor fan motor.
Replace the indoor fan motor.
Replace the indoor electronic control P.C. board.
No
(Changed)
Yes
(Unchanged)
28
(+) and (-).
(+) and (-).
CN211
Indoor electronic
control P.C. board