MXZ-SM36NAMHZ Service Manual
76
OCH789
Check code
4210
(UP)
Chart 2 of 2
Compressor overcurrent interruption/failure in
12 VDC power supply circuit on power circuit board
â—ŹDiagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Diagnosis Remedy
No
Yes
Yes
No
Yes
Yes
No
Yes
No
No
Are they connected properly?
Connect the compressor wiring (U, V and
W phase) properly, then turn the power
back ON.
Continued from the previous page.
Does it operate normally?
Are those units short-cycled?
Are the voltage among the phases
U-V, V-W and W-U di󰀨erent?
Does it operate normally?
Check the DC fan motor.
Resolve the short-cycle.
Replace the compressor.
Replace the outdoor power circuit board.
Complete.
Check the operation of indoor/outdoor fan
motors.
Check for indoor/outdoor short-cycle.
Disconnect the compressor wiring from the outdoor
power circuit board, then check the voltage among
each phases U, V and W during test run (SW7-1 ON).
Make sure to perform a voltage
check with the same performing
frequencies.
Replace the outdoor multi controller circuit
board.
(short-cycled)
(no short-cycled)