<Wiring connection procedure>
U1 U2
U3 U4
N
Power supply
L
ON-OFF controller
When connecting to VRF outdoor
units (when connecting to the
central control system wire)
<Grounding the shielded wires>
U1 U2
U3 U4
Power supply
ON-OFF controller
When connecting to multiple
outdoor units (when
connecting to the central
control wiring)
Area A: Ground both ends of the shielded cable used for the indoor/outdoor
unit connection.
Area B: Connect a shielded cable for the central control system wiring.
Area C: Ground only one end of the central control system wiring at its final
termination. (Leave the other end of the wire at its final termination as an
open wire (i.e. insulate it).)
OI-744-09EG
As shown in the figure below, connect the terminal block (U1/U3, U2/U4) of the
ON-OFF controller with the terminals (U3, U4) of the outdoor unit (Header unit).
•
It is also possible to connect to the indoor/outdoor unit connecting wire
terminals (U1, U2) of the indoor or outdoor unit (no matter which refrigerant
system is used).
•
Since the terminals do not have polarities, U1/U2 or U3/U4 can be reversed.
Central control
wiring
U1 U2 U3 U4
Indoor/outdoor unit
connecting wire
U1 U2
The fuse will blow to protect the equipment if an AC voltage of 220–240V is
NOTE
applied by mistake to U1/U3 or U2/U4. If this should happen, first re-connect
the terminals properly, and then connect the communication wire to the U1/U3
and spare terminals. Check the fuse on the indoor/outdoor control board
since this fuse may have blown as well.
•
Terminate the connection of the shielded wires for all the central control
wires, and provide single-point grounding.
•
Even when connecting the centrally controlled unit to the indoor/outdoor unit
connecting wires, terminate the connection of the shielded wires, and
provide single-point grounding for all the indoor/outdoor unit connecting
wires.
•
Leave the final termination open (insulate it).
B
Central control system wire
Indoor/outdoor
unit connecting
wire shield
(single-point
U1 U2 U3 U4
grounding)
Indoor/outdoor
unit connecting
wire
U1 U2
VRF Outdoor unit
(Header unit)
Indoor unit
U1 U2
Power supply
Outdoor unit (Header unit)
B
A
A
Indoor unit
U1 U2
Power supply
ON-OFF controller
When connecting to multiple indoor
units (when connecting to the
indoor/outdoor unit connecting wire)
ON-OFF controller
When connecting to MMO
indoor units (when connecting
to the indoor/outdoor unit
connecting wire)
U1 U2
U3 U4
Weekly timer
N
L
Fig. 5
U3 U4
C
Central control
wiring shield
(single-point
grounding)
U1 U2
U3 U4
Weekly timer
Fig. 6
EG
9