Mitsubishi Electric City Multi PUMY-SP112VKM Technical & Service Manual page 107

Check method of DC fan motor (fan motor/outdoor multi controller circuit board)
Notes
1
· High voltage is applied to the connecter (CNF1) for the fan motor. Pay attention to the service.
· Do not pull out the connector (CNF1) for the motor with the power supply on.
(It causes trouble of the outdoor multi controller circuit
Self check
2
Symptom : The outdoor fan cannot rotate.
Fuse check
Check the fuse (F500) on outdoor
multi controller circuit board.
Did the fuse blow?
No
Wiring contact check
Contact of fan motor connector (CNF1)
Is there contact failure?
No
Power supply check (Remove the connector (CNF1))
1 While the breaker is OFF, disconnect the compressor wirings (U/V/W) from the outdoor power circuit board.
2 While the breaker is OFF, disconnect the fan motor connector CNF1.
3 When 5 minutes have passed since turning ON the breaker, turn SW7-1 ON.
4 Check the voltage of the outdoor multi controller circuit board.
Measure the voltage in the outdoor controller circuit board.
TEST POINT 1: VDC (between 1 (+) and 4 (−) of the fan connector): 310–340 V DC (Y)
: VDC (between 1 (+) and 4 (−) of the fan connector): 280–340 V DC (when PFC module stops),
TEST POINT 2: VCC (between 5 (+) and 4 (−) of the fan connector): VCC 15 V DC
TEST POINT 3: VCC (between 6 (+) and 4 (−) of the fan connector): VCC 0–6.5 V DC
Is the voltage normal?
No
Replace the outdoor multi
controller circuit board.
Check the operation.
Fail
Replace the fan motor.
Note:
・ Turn SW7-1 OFF after the troubleshooting completes.
・ The fan sometimes starts on-off cycle operation during low-load operation or cooling at low outside temperature.
It is not abnormal; the operation ensures reliability of the product.
OCH668B
board and fan motor.)
Disconnect the FAN motor connector and
Yes measure the resistance of connector pins.
Refer to "8-5. HOW TO CHECK THE PARTS".
Recover wiring.
Yes
Replace the fan motor.
Yes
Check the operation of fan.
Replace the outdoor multi controller circuit board.
OK
COMPLETE
107
Replace the outdoor multi controller
circuit board (MULTI.B.) and the fan
motor.
: 380 V DC (when PFC module is operating) (V)
Yes OK
Fail
COMPLETE