Nobu NBL4-18IDU32 Service Manual page 56

(4) Charging Malfunction of Capacitor (PU)
Main check point:
Whether input power is normal?
Main board is damaged.
Malfunction diagnosis process:
Check the input power and
resume the power supply
normal
Is malfunction eliinated?
70
52
No
No
Yes
Energize and turn on the unit;
wait for 1 min
Measure the voltage at
both ends of big electrolytic
capacitor with the DC notch of
universal meter
Is the voltage more than
100V?
No
Check whether the input
voltage is within the normal
range?
Yes
Replace main board of
outdoor unit
End
Service Manual
Service Manual
There is malfunction for the
Yes
detection circuit on main
board of outdoor unit
Installation and Maintenance
Installation and Maintenance