Service Manual

Trouble shooting 76
No Operation (Power is ON)
Check Point 2 : Check outside cause at Indoor unit, RB Unit, and Outdoor unit (Voltage drop or Noise)
Check Point 1 : Check indoor, RB Unit and outdoor installation condition
Check Point 3 : Check Electrical Components at Indoor unit, Outdoor unit and RB Unit
Indoor Unit - Check the voltage between pins 1-3 of the connector (on the control PCB) for connection with the remote controller.
>> If it is DC12V, Remote Control is defective (Controller PCB is normal) >> Replace Remote Control
>> If it is DC 0V, Controller PCB is defective (Check Remote Control once again) >> Replace Controller PCB
If some of Indoor unit does not operate, replace the Communication PCB of the non-operative Indoor Unit.
>> If the symptom does not change, replace Controller PCB of Indoor Unit.
If all of Indoor Units do not operate, check the connection between Main PCB and Communication PCB of Outdoor Unit (Main Unit).
>> If the symptom does not change, replace Communication PCB of Outdoor Unit (Main Unit).
(If it did not work, replace Main PCB.)
Turn off Power and check/correct followings.
Isn't Communication PCB of Indoor Unit removed?
Is there loose or removed communication line of Indoor Unit and Outdoor Unit?
Check Terminator (DIP-SW SET 5) is installed on Outdoor Main PCB.
Check loose or removed communication line between each Outdoor Unit.
Check loose Communication PCB of each Outdoor Unit.
OK
OK
OK
DC
Forecast of Cause :
1. Setting/Connection failure 2. Outside cause
3. Electrical Component defective
Indoor Unit - Check incorrect wiring between Indoor Unit - Remote Control, or terminals between Indoor Units.-
Or, check if there is an open cable connection.
Check address setting (Are all the address of Indoor unit, Outdoor unit and RB unit correct?)
Are these Indoor Unit, RB Unit, Outdoor Unit, and Remote Control suitable model numbers to connect?
>> If there is some abnormal condition, correct it by referring to Installation manual and Design & Technical Manual.
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.
Check network cable connection between Indoor unit - Outdoor unit - RB Unit.
Check loose Communication PCB of each controller PCB inside RB Unit.
In case of 2 wires WRC, Check the voltage between pins 1-2.
>> If the symptom does not change, replace Transmission PCB of RB Unit.
>> If the symptom does not change, replace Controller PCB of RB Unit.
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