Fujitsu AUXB04GALH Service Manual page 98

Trouble shooting 13
OUTDOOR UNIT Error Method:
Auto Address Setting Error
<< After Indoor unit Auto Adress setting >>
Detective Actuators:
Outdoor unit Main PCB
Forecast of Cause :
Check Point 1 : Check the indoor unit power supply
Check the indoor unit power supply
OK
Check Point 2 : Check the indoor unit number connection
Check if more than 64 indoor units are connected in a refrigerant circuit
OK
Check Point 3 : Check the communication line connection
Check if communication line is correctly connected
Is it uncoupled or cut halfway ?
Connecting terminal position is correct as the installation manual shows ?
OK
Check Point 4 : Check noise, momentary open, voltage drop
Check if power supply temporarily stops by outages or if strong noise is generated from
surrounding environment during auto address
Indicate or Display:
E28. 1
Outdoor Unit : E. 28. 1
Indoor Unit
Error Code
Detective details:
When none of the connected indoor units answers during auto address
And when abnormal answer signal is input.
1. Indoor unit power supply defective
3.Communication line incorrect connection
: No Display
: No Display
* Service tool does not indicate the Error code
2. Indoor unit overconnected
4. Noise, momentary open
04-22