MXZ-SM42NAMHZ Service Manual

75
OCH789
Check code
4210
(UP)
Chart 1 of 2
Abnormal points and detection methods Causes and checkpoints
If overcurrent of compressor is detected after 30 seconds since the
compressor starts operating.
If 12 VDC power is not supplied from the 12 VDC supply circuit on the
power circuit board.
Closed outdoor stop valve
Decrease of power supply voltage
Looseness, disconnection or reverse phase of
compressor wiring connection
Malfunction of indoor/outdoor fan
Short-cycle of indoor/outdoor unit
Model selection error upon replacement of outdoor
multi controller circuit board
Malfunction of input circuit on outdoor multi controller
circuit board
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
No
No
No
8
7
Is the stop valve (liquid/gas) fully
open?
Is the power supply voltage normal?
Are they set properly?
Open the stop valve (liquid/gas) fully.
Check the power supply facility
(check for power supply open phase).
Set the model selection correctly.
Check the outdoor stop valve.
Check whether the power supply voltage is
normal or not.
Check whether the model selection switch is set correctly
on the outdoor multi controller circuit board or not.
Turn the power OFF to check for looseness, disconnection
or converse phases of the compressor
wiring.
Continue to the next page.
Which sub code is displayed?
Replace the outdoor power circuit board
(Defective outdoor power circuit board).
ON
OFF
1 2 3 4 5 6 7 8
SW1 Setting
Display on LED1,2
1
2 3 4 5 6 7 8
7: 12 V power supply circuit trouble
8: Overcurrent trouble
The sub codes are displayed by an
operation of SW1 on the outdoor
mutli controller circuit board.
Compressor overcurrent interruption/failure in
12 VDC power supply circuit on power circuit board