Service Manual

SiUS281811E Troubleshooting by Error Codes
Part 6 Service Diagnosis 255
Troubleshooting
 The number of indoor units that may be connected to an individual outdoor unit system is
determined by the model of the outdoor unit.
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
YES
YES
YES
YES
NO
NO
NO
NO
Is the outdoor unit PCB
replaced by the backup PCB?
Is the refrigerant type of
the indoor unit and outdoor unit
matched?
Is the total number of
indoor units displaying UA
and indoor units connectable to the
same refrigerant system
within the permitted
limit?

Press RESET (BS5) button on the
outdoor unit PCB for 5 seconds.
Is any fault detected?
Check the model name of the
outdoor unit PCB and then
replace the old one.
Too many indoor units under one
refrigerant system.
Normal
Match refrigerant type of indoor
unit and outdoor unit.
Replace the outdoor main PCB
(A1P).