Gree GMV-VQ280WM/C-X Owner's Manual page 53

GMV Heat Recovery DC Inverter VRF
The connection between the indoor unit and the wired controller is shown as below:
(2) Selection of communication line between outdoor unit and indoor unit.
Wire type
Light / ordinary PVC
sheathed twisted copper
core cord
Shielded light/ordinary PVC
sheathed twisted copper
core cord
3.9.3Communication method
Communication bus connection between indoor unit，mode exchange box and outdoor unit must
be connected in series, rather than star connection; the endmost indoor unit of communication bus
between indoor unit，mode exchange box and outdoor unit must connect with the communication
matching resistor(in the outdoor unit plastic bag); The fresh air indoor unit is not recommended to be
set as the main indoor unit.
Connection of communication wire
(1) Communication wires of heat recovery units must be connected in series instead of in star
mode;
Fig.3.9.2
Length of
communication
Wire diameter
line between
indoor unit and
wired controller(m)
L≤1000 ≥2×0.75
L≤1000 ≥2×0.75
Fig.3.9.3
Wire standard
(mm )
2
IEC 60227-5:2007
IEC 60227-5:2007
49
Remark
If the wire diameter is
increased to 2×1mm , the
2
length of communication line
can't be increased, while the
length of the communication
line can't be more than
1500m.
When the installation
environment of the unit is in
strong magnetic or strong
interference, the shielded
wires shall be used.