Fujitsu Comfort Series Service Manual page 29

Troubleshooting 3
HYDRAULIC UNIT Error Method:
Combination error
Detective Actuators:
Hydraulic unit interfase PCB
Forecast of Cause:
1. The combination of hydraulic unit and outdoor unit is incorrect
Check Point 1 : Check the type of hydraulic unit and outdoor unit
Check the type of the connected hydraulic unit and outdoor unit.
>> If abnormal condition is found, correct it.
OK
Check Point 2 : Replace Main PCB
If Check Point 1 do not improve the symptom, replace PCB hydraulic unit or outdoor unit.
Indicate or Display:
Green 2 flash / Red 3 flash
Detective details:
1. The outdoor unit receives the serial signal of applied refrigerant
information from hydraulic unit. When the refrigerant is R410a.
2. The combination of Hydraulic unit and Outdoor unit isn't alloed.
03-04
Outdoor unit : No indication