59
Installation and Maintenance
Service Manual
(7) Communication malfunction: (following AP1 for outdoor unit control board)
Mainly detect:
●Is there any damage for the indoor unit mainboard communication circuit? Is communication circuit damaged?
●Detect the indoor and outdoor units connection wire and indoor and outdoor units inside wiring is connected well or not, if is there any
damage?
Fault diagnosis process:
Y
N
Y
N
N
Y
N
N
Y
N
Y
N
Y
Y
Start
Did the equipment operate
normally before the failure
occurs?
The AP1 voltage
detection circuit
is at fault
units
Check wiring inside of
the indoor and outdoor
Are wires broken?
If the fault is eliminated?
Check the communication
circuit of the outdoor unit
The communication
circuit is abnormal
If the fault is eliminated?
End
Replace the main board
of the indoor unit
If the fault is eliminated?
Replace the main board
AP1 of the outdoor unit
Is the connection right?
Check the wiring of the indoor and
outdoor units with reference to the
wiring diagram
Correctly connect the
corresponding wires for
the indoor and outdoor
units with reference to
the wiring diagram
