Mitsubishi Electric PUMY-SP112VKM.TH Technical & Service Manual page 70

Check code
4400
(U8)
Abnormal points and detection methods
If no rotational frequency is detected, or detected a value outside the
specified range during fan motor operation.
●Diagnosis of defects
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.
Has the fuse melted?
Check the fan motor connector (CNF1) for
disconnection or looseness.
Is there any abnormality such
as 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 VDC (fan connector 1–4)
· VCC approx. 15 VDC (fan connector 5–4)
· VCC approx. 0–6.5 VDC (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.
OCH668G
Fan trouble (Outdoor unit)
Diagnosis
(melted)
(Not melted)
No
No
Yes
Causes and checkpoints
1. Malfunction of fan motor
2. Disconnection of CNF connector
3. 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 8-5.
Connect the wiring/connector properly.
Yes
Replace it in the case of breakage.
Replace the outdoor multi controller circuit
No
board.
Replace the defective fan motor.
70
Remedy