Mitsubishi Electric PUMY-P36NKMU3 Technical & Service Manual page 66

Check code
4210
(UP)
Abnormal points and detection methods
If overcurrent of DC bus or compressor is detected after 30 seconds since
the compressor starts operating.
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Check the outdoor stop valve.
Is the stop valve (liquid/gas) fully
open?
Check whether the power supply voltage is
normal or not.
Is the power supply voltage normal?
Check if the model selection switch is set
correctly on the indoor controller board or
outdoor multi controller circuit board.
Turn the power OFF to check for
looseness, disconnection, or wrong phases
of the compressor wiring.
Continue to the next page.
OCH733
Compressor overcurrent interruption
Diagnosis
Yes
Yes
Are they set properly?
Yes
Causes and checkpoints
Closed outdoor stop valve
Decrease of power supply voltage
Looseness, disconnection, or wrong phase of
compressor wiring connection
Model selection error on indoor controller board or
outdoor multi controller circuit board
Defective compressor
Defective outdoor power circuit board
Defective outdoor multi controller circuit board
Malfunction of indoor/outdoor unit fan
Short-cycle of indoor/outdoor unit
Open the stop valve (liquid/gas) fully.
No
• Check the looseness, disconnection, or
breakage of compressor wiring.
No
• Ensure power supply from the facility.
(Check for power supply open phase.)
Set the model selection correctly.
No
66
Chart 1 of 2
Remedy