Midea MS9A-05CR-QD0 Service Manual page 60

9.2.6 Indoor / outdoor units communication error diagnosis and solution
Power off, then turn on the unit 5 seconds
later(reconnect the power wire).Is the error
still displaying after several minutes?
Check all the wirings between indoor and
outdoor, indoor main PCB and outdoor main
PCB following the wiring diagram. Are all
the wirings connected correctly?
Measure Vs, is it moving alternately
between positive value and negative
value?
(Vs is the voltage between S and N of
outdoor unit.)
Is the wiring to the outdoor m a i n
PCB connected correctly?
Change the outdoor main PCB.
Power on. Is the error extinguished?
Change the indoor main PCB.
Yes
Yes
Yes
Yes
No
No
Is the wiring to the indoor main
PCB connected correctly?
Yes
Change the indoor main PCB.
Power on. Is the error extinguished?
No
Change the outdoor main PCB.
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