Daikin Aurora Series, Service Manual, Page: 286 / 333

Troubleshooting by Error Code SiUS341802E
273 Service Diagnosis
Diagnosis Flowchart-4
NO
Disconnect residential indoor units
from the system.
Are all
indoor units for
VRV? (no residential
indoor units)
Error code Sub code
UA-21
NO
YES
YES
YES
NO
NO
Replace the outdoor unit main PCB
(A1P).
Check for the model of outdoor
unit.
Make setting again, and then
reset the power supply.
Replace the spare PCB.
NO
YES
Replace the outdoor unit main PCB
(A1P).
Was the
outdoor unit PCB
replaced with a spare
PCB?
A
different model
of outdoor unit is
connected.
YES
Replace the outdoor unit main PCB
(A1P) .
Diagnosis Flowchart-3
Error code Sub code
UA-20
Multi connection?
Was proper setting
of spare PCB
made?