Fujitsu AMUG24LMAS Service Manual page 55

Troubleshooting 2
Serial communication error
(Serial forward transfer error)
Detective details:
When outdoor unit cannot properly receive
serial signal from indoor unit for 10 seconds
or more.
Forecast of cause:
1. Connection failure
2. External cause
3. Controller PCB failure
Check Point 1-1 : Reset the power and operate
Does error indication reappear?
YES YES
Check Point 2 : Check connection
Check any loose or removed connection line of
between indoor unit and outdoor unit.
>> If there is an abnormal condition, correct it by
referring to Installation Manual or Data &
Technical Manual.
Check connection condition in control unit.
(If there is loose connector, open cable or mis-wiring)
OK
Check Point 3 : Check the voltage of power supply
Check the voltage of power supply
>> Check if AC187V (AC208V-10%) - 253V (AC230V+10%) appears
at outdoor unit terminal L1 - L2.
OK
Check Point 4 : Check serial signal (Forward transfer signal)
Check serial signal (Forward transfer signal)
>> Check if indicated value swings between AC30V and AC130V at outdoor unit terminal 2 - 3.
>> If it is abnormal, replace Controller PCB.
BLACK 1
2
WHITE
RED 3
L1
BLACK
L2
WHITE
NO
Check Point 1-2 : Check external cause such as noise
Check if the ground connection is proper.
Check if there is any equipment that causes harmonic wave
near the power cable (Neon light bulb or any electronic
equipment which causes harmonic wave).
+
-
03-07
Indicate or Display:
Indoor unit
Operation lamp: 1 time Flash,
Timer lamp : 1 time Flash
Wired remote control
Error code : [E : 11]
Outdoor unit (AOUG36/48LMAS1)
Mode Error A B
2 1 1
Mode Error A B
2 1 1
: Light OFF : Light ON
C D E F
C D E F
n : n times blinking