Yes
Yes
Measure Vs, is it moving alternately
with positive value?
(Vs is the voltage between L2 and S
of outdoor unit. Connect the red pin of
multimeter with L2 port, black pin with
S port)
Yes
Power off, then turn on the unit 5 seconds
later(reconnect the power wire).Is the error
still displaying after several minutes?
No
Replace the outdoor main PCB.
Power on. Is the error extinguished?
Check all the wiring with indoor units.
Is the wiring to the indoor main PCB
connected correctly?
Replace the indoor main PCB.
Yes
Replace the outdoor main PCB.
No
Check all the wiring with outdoor
u ni t s. Is the wiring to the outdoor
main PCB connected correctly? Is
the reactor connected well?
Power on. Is the error extinguished?
Replace the indoor main PCB.
No
Yes
Measure the resistance of the
reactor(The one without capacitor).
If it is zero ,follow the below step. If
not, replace a new reactor.