MXZ-SM48NAM Service Manual

80
OCH789
Check code
4250
(U6)
Power module trouble or overcurrent trouble
Abnormal points and detection methods Causes and checkpoints
If overcurrent of DC bus or compressor is detected 30 seconds after the
compressor starts operating. To determine the source of abnormality,
either the compressor or the power module, drive the power module
forcedly.
Closed outdoor stop valve
Decrease of power supply voltage
Disconnection, looseness or conversed connection
of compressor wiring
Defective compressor
Defective outdoor power circuit board
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Diagnosis Remedy
Yes
Yes
Yes
Yes
No
No
No
No
Is the stop valve (liquid/gas) fully
open?
Is the power supply voltage normal?
Are the wirings normal?
Does it operate normally?
Open the stop valve (liquid/gas) fully.
Ensure power supply from facility.
Connect the compressor wiring (U, V and
W phase) properly, then turn the power
back ON.
Replace the outdoor power circuit board
or outdoor multi controller circuit board
(Defective power circuit board).
Replace the compressor
(Defective compressor).
Check the outdoor stop valve.
Check whether the power supply voltage is
normal or not.
Turn the power OFF to check for
looseness, disconnection or phases of the
compressor wiring.
Disconnect the wiring to check the power
module.