Gree GWH12UB-K3DNA4F Service Manual page 80

Service Manual
9. Communication malfunction (AP1 below is control board of outdoor unit)
Main detection point:
● Check if the connection wire and the built-in wiring of indoor and outdoor unit is connected well and no damaged;
● If the communication circuit of indoor mainboard is damaged? If the communication circuit of outdoor mainboard (AP1) is dam-
aged
Malfunction diagnosis process:
Malfunction of
circuit is
detected with
control board
AP1 voltage
If the malfunction
is removed?
Y
Installation and Maintenance
Yes
Check built-
in wiring of
indoor and
outdoor unit
If the wiring is
Yes
damaged?
No
Check communication
No
circuit of outdoor unit
Problem of
communication
circuit
No
Replace indoor
board
Start
If the unit is operation
normal before malfunction
Y
Yes
Replace outdoor
Yes
Y
mainboard AP11
If the
malfunction is
removed?
No
Yes Y
End
No N
Check connection
wire of indoor and
outdoor unit with
circuit diagram
Connection
correct?
No
N
No
Check connection
wire of indoor and
outdoor unit with
circuit diagram
If the malfunction
is removed?
Yes
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