yes
if wiring between P and
Q is wrong or broken down
no
no
no
yes
yes
no
if wire of CN15 on
indoor PCB is normal
if wire of CN29 on outdoor
connecting board is normal
if indoor and outdoor are
electrified at the same time
if communication wire is
separate from high-voltage
wire on layout
if indoor quantity is
correct (check by rotary switch)
yes
modify the communication wire
modify the port
connect power source
change communication
wiring type
no
shut off power supply, and outdoor
searches for indoors again
check outdoor PCB, if faulty, replace it
yes
no
yes
if failure disappears
after changing indoor PCB
yes
no
eliminate noise source
no
if there is noise source
[26-0,26-1,26-2] communication circuit between indoor and outdoor
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