Ground - Mitsubishi Electric City Multi PUMY-SP112VKM Technical & Service Manual

Check code
4400
(U8)
Abnormal points and detection methods
Abnormal if no rotational frequency is detected, or detected a value
outside the specified range during fan motor operation.
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Check the fuse on the outdoor multi
controller circuit board.
Is the fuse melting?
Check the fan motor connector (CNF1) for
a disconnection or looseness.
Is there any abnormality such
as a disconnection, looseness or
breakage?
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.
Test points are;
· VDC approx. 310 to 380 V DC (fan connector 1–4)
· VCC approx. 15 V DC (fan connector 5–4)
· VCC approx. 0–6.5 V DC (fan connector 6–4)
Is the voltage normal?
Notes
・Set 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
Fan trouble (Outdoor unit)
Diagnosis
(melting)
No (Not melting)
No
Yes
Causes and checkpoints
Malfunction of fan motor
Disconnection of CNF connector
Defective outdoor multi controller circuit board
• Replace the outdoor multi controller circuit board.
Yes
• Replace the defective fan motor.*
*For the detail, refer to "Check method of DC
fan motor (fan motor/outdoor multi controller
circuit board)" in chapter 8-7.
Connect the wiring/connector properly.
Yes
Replace it in case of a breakage.
Replace the outdoor multi controller circuit
No
board.
72
Remedy
Replace the fan motor.