Fujitsu Airstage J-II - The Number of Indoor Unit Shortage

Trouble shooting 48
OUTDOOR UNIT Error Method:
The number of Indoor unit shortage
Indicate or Display:
Indoor Unit : No display
Outdoor Unit : E.1 4.5
Error Code : No display
Detective Actuators:
Indoor unit Controller PCB circuit
Indoor unit Communication PCB
Detective details:
When the indoor unit number decreases for 180 seconds from the memorized
maximum indoor units number after power(Breaker) ON.
04-57
OK
Communication PCB connection check
Communication PCB check
OK
Communication line connection, open check
OK
OK
Check Point 5 : Check the communication PCB (indoor unit / outdoor unit)
OK
1. Indoor unit power off 2. Noise, momentary open, voltage drop
3. Communication line connection defective 4. Terminal resistor setting mistake
5. Communication PCB mounting defective, Communication PCB defective 6. Controller PCB defective
Check Point 2 : Noise, momentary open, voltage drop
Check if temporary voltage drop was not generated.
Check if momentary open was not generated.
Check if ground is connection correctly or there are no related cables near the power line.
Check Point 2 : Check the indoor unit power supply
Main power ON check
Power cable connection and open check
Check Point 3 : Check the communication line connection
Check Point 4 : Check the Terminal resistor setting
T
erminal resistor setting check
Check Point 6 : Replace Main PCB and Communication PCB (indoor unit / outdoor unit)
Change Main PCB and Communication PCB, and set up the original address.
Forecast of Cause :
Check Point 1 : Find the indoor unit that the communication is lost.
Check system drawing and service tool.
OK
Attention!!
Even if this error occurs, system does not stop.
If the failure indoor unit is pinpointed and it needs
to erase the error indication, it can be reset by
function setting (F3-41: Maximum memorized
indoor unit number reset).