Daikin RXQ12AHR Service Manual page 284

Troubleshooting by Error Code
278
Diagnosis Flowchart-1
UA-17
Error code Sub code
The
number of indoor
units connected to the
same system is not
more than 64.
NO
Diagnosis Flowchart-2
UA-18
Error code Sub code
Check if the
refrigerant type of
the outdoor unit
corresponds to that
of the indoor
unit.
NO
Diagnosis Flowchart-3
UA-20
Error code Sub code
Multi connection?
YES
Was the
outdoor unit
main PCB replaced with a
spare PCB?
YES
Was proper setting of
spare PCB made?
YES
YES
YES
NO
A
NO
NO
different model
of outdoor unit is
connected.
YES
NO
SiAF341904E
Replace the outdoor unit main
PCB (A1P).
Excess indoor units are
connected.
Check for the connection to
connect the proper number of
indoor units.
Replace the outdoor unit main
PCB (A1P).
Match the refrigerant types of the
outdoor unit and the indoor unit.
Replace the outdoor unit main
PCB (A1P).
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.
Part 6 Service Diagnosis