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

Check code
4250
(U6)
Abnormal points and detection methods
Abnormal 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 defectives
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
OCH668B
Power module trouble or Overcurrent trouble
Diagnosis
Yes
* SW7-1 ON: Ignore 5300(UH) error.
displayed?
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).
71
Remedy