Mitsubishi PUMY-P60NKMU Technical & Service Manual page 52

Check code
4210
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Continued from the previous page
Are they connected properly?
Check the operation of indoor/outdoor fan
motors.
Does it operate normally?
Check for indoor/outdoor short-cycle.
Are those units short-cycled?
Disconnect the compressor wiring from the outdoor
power board, then check the voltage among each
phases U, V and W during test run (SW7-1 ON).
Are the voltage among the phases
U-V, V-W and W-U different?
Replace the outdoor controller board.
Does it operate normally?
OCH502C
Compressor overcurrent interruption
Diagnosis
No
Yes
No
Yes
Yes
(short-cycled)
(no short-cycled)
No
Make sure to perform a voltage
check with the same performing
frequencies.
No
Yes
No
Yes
Connect the compressor wiring (U, V and
W phase) properly, then turn the power
back ON.
Check the DC fan motor.
Remove factor(s) causing the short-cycle.
Replace the compressor.
Replace the outdoor power board.
52
Chart 2 of 2
Remedy
Complete.