Measure  Vs, is it  positive fluctuation?
(Vs is the voltage between 3 and 2 of 
outdoor unit. Red pan-3, Black pan-2)
Measure  Vs, is it  positive fluctuation?
(Vs is the voltage between 3 and 2 of 
outdoor unit. Red pan-3, Black pan-2)
Yes
Power off, then restart the unit 2 minutes later
Power off, then restart the unit 2 minutes later
No
Replace the outdoor main PCB.
Power on. Is the error 
extinguished?
Replace the outdoor main PCB.
Power on. Is the error 
extinguished?
 Check the outdoor wiring connection
 Check the outdoor wiring connection
Replace the indoor main PCB.
Power on. Is the error 
extinguished?
Replace the indoor main PCB.
Power on. Is the error 
extinguished?
Yes
Replace  the outdoor main PCB.
Replace  the outdoor main PCB.
No
Replace the indoor main PCB.
Replace the indoor main PCB.
No
 Check the indoor wiring connection
 Check the indoor wiring connection
Yes
Yes
Check whether reactor 
is normal?
Check whether reactor 
is normal?
Yes
Replace  the reactor
Replace  the reactor No