Gree GRH120DB-K6NA1A Service Manual page 38

7. Communication malfunction E6
The AP1 voltage
detection circuit
is at fault
If the fault is eliminated?
Yes
36
Yes
Check wiring inside
of the indoor and
outdoor units
Yes
Are wires broken?
No
Check the communication
No
circuit of the outdoor unit
The communication
circuit is abnormal
No
Replace the main board
of the indoor unit
Start
Did the equipment operate
normally before the failure
occurs?
Yes
Replace the main board
Yes
AP1 of the outdoor unit
If the fault is eliminated?
No
Yes
End
No
Check the wiring of the indoor and
outdoor units with reference to the
wiring diagram
Is the connection right?
No
No
Correctly connect the
corresponding wires for
the indoor and outdoor
units with reference to
the wiring diagram
If the fault is eliminated?
Yes
Installation and Maintenance