Mitsubishi Electric PUMY-P112VKM4 Technical & Service Manual page 78

Check code
4250
(U6)
Abnormal points and detection methods
If both of the following conditions have been satisfied:
1. Overcurrent of DC bus or compressor is detected during compressor
operation.
2. Inverter power module is determined to be defected.
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Turn the power OFF to check for looseness
or disconnection of the compressor wiring.
Are they connected properly?
1 Disconnect the compressor wiring
(U-V-W phase).
2 Turn ON the SW7-1(*) on the outdoor
multi controller circuit board.
3 Operate the unit.
Is the check code <4250> still
displayed?
OCH673D
Power module trouble
Diagnosis
Yes
* SW7-1 ON: Ignore 5300(UH) error.
Yes
Causes and checkpoints
Short-circuit caused by looseness or disconnection
of compressor wiring
Defective compressor
Defective outdoor power circuit board
Connect the compressor wiring (U, V and
W phase) properly, then turn the power
No
back ON.
Replace the compressor
No
(Defective compressor).
Replace the outdoor power circuit board or
the outdoor multi controller circuit board
(Defective outdoor power circuit board).
78
Remedy