Mitsubishi Electric PUMY-P36NKMU4 Technical & Service Manual page 80

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 controller
board.
Has the fuse melted?
Check the fan motor connector (CNF1 and
CNF2) for a 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 and
CNF2.
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 350 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 on HP36/42/48.
It is not abnormal; the operation ensures reliability of the product.
OCH811A
Diagnosis
(Melted)
(Not melted)
No
No
Yes
Fan trouble
Causes and checkpoints
Malfunction of fan motor
Disconnection of CNF connector
Defective outdoor controller board
Replace the outdoor controller 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 the case of a breakage.
Replace the outdoor controller board.
No
Replace the defective fan motor.
80
Remedy
z