Fujitsu AMUG24LMAS, Service Manual

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Troubleshooting 31
Forecast of cause:
OK OK
Indoor unit - No power
1. Power supply failure
2. External cause
3. Electrical Components defective
Check Point 1 : Check Installation Condition
Isn’t the breaker down?
Check loose or removed connection cable.
>>If abnormal condition is found, correct it by referring
to Installation Manual or Data & Technical Manual.
Check Point 2 : Check external cause at indoor and outdoor (voltage drop or noise)
Instant drop ----- Check if there is a large load electric apparatus in the same circuit.
Momentary power failure ----- Check if there is a defective contact or leak current in
the power supply circuit.
Noise ----- Check if there is any equipment causing harmonic wave near electric line.
(Neon bulb or electric equipment that may cause harmonic wave)
Check the complete insulation of grounding.
03-43
Check Point 3 : Check electrical components
YES YES
OK
NO
Check the voltage of power supply.
>> Check if AC187 - 253V appears at outdoor unit terminal L1 - L2.
Check Varistor in Filter PCB.
>> If Varistor is defective, there is a possibility of an abnormal power supply.
Check the correct power supply and replace Varistor.
Upon checking the normal power supply, replace Varistor.
If the symptom does not change by above check 3, replace main PCB.
OK
Check Fuse in Filter PCB.
>> If Fuse is open, check if the wiring between Terminal and Filter PCB
is loose, and replace Fuse.