Gree GWH18TC-S3DNA1D Service Manual page 83

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?
Yes Y
80
Yes Y
Check built-
in wiring of
indoor and
outdoor unit
If the wiring is
Yes Y
damaged?
No
N
Check communication
No N
circuit of outdoor unit
Problem of
communication
circuit
No N
Replace indoor
board
Start
If the unit is operation
normal before malfunction
Yes
Y
Replace outdoor
Yes
Y
mainboard AP11
If the
malfunction is
removed?
No
N
Yes Y
End
No
N
Check connection
wire of indoor and
outdoor unit with
circuit diagram
Connection
correct?
No N
No N
Check connection
wire of indoor and
outdoor unit with
circuit diagram
If the malfunction
is removed?
Yes
Y
Installation and Maintenance
Service Manual