MXZ-SM48NAMHZ Service Manual

114
OCH789
1. Notes
• High voltage is applied to the connecter (CNF1, 2) for the fan motor. Pay attention to the service.
• Do not pull out the connector (CNF1, 2) for the motor with the power supply on.
(It causes trouble of the outdoor multi controller circuit
board and fan motor.)
2. Self check
Symptom: The outdoor fan cannot rotate.
Check method of DC fan motor (fan motor/outdoor multi controller circuit board)
Power supply check(Remove the connector (CNF1, 2))
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, 2.
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 multi controller circuit board.
TEST POINT 1: VDC (between 1 (+) and 4 (-) of the fan connector): VDC 290–330 V DC(When PAM stops), 380 V DC (When PAM is operating)
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
No
Fail
Fail
Wiring contact check
Contact of fan motor connector (CNF1, 2)
Fuse check
Check the fuse (F500) on outdoor
controller board.
Correct the wiring.
Is the fan motor normal?
Replace outdoor multi controller circuit board.
Replace defective the fan motor.
Replace defective the fan motor.
Replace outdoor multi
controller circuit board.
Is the voltage normal?
Is there contact failure?
Yes
Yes
No
Did the fuse blow?
No
Yes
Check the operation of fan. Complete.
Yes
OK
Check the operation.
OK
Disconnect the FAN motor connector and
measure the resistance of connector pins.
Refer to “8-7. HOW TO CHECK THE PARTS”.
Replace outdoor multi controller circuit board
(MULTI.B.) and the defective fan motor.
Replace outdoor multi controller
circuit board (MULTI.B.).
Complete.
No
Yes
Note: Turn SW7-1 OFF after the troubleshooting completes.
The fan sometimes starts on-o󰀨 cycle operation during low-load operation or cooling at low ambient temperature.
It is not abnormal; the operation ensures reliability of the product.