46 | ELECTRICAL CONNECTIONS
MUL
TI V S Three-Phase Outdoor Unit Engineering Manual
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THREE-PHASE
ELECTRICAL CONNECTIONS
• For power wiring, use solid or stranded that must comply
with all local and national electrical codes.
• Connect the communications cable between indoor units
using a daisy chain configuration only. “Star” or “home run”
control wiring connections involving soldering or wire caps
are not permitted.
• Communication cable between outdoor unit to indoor units
must be a minimum of 18 AWG, 2-conductor, twisted,
stranded, shielded. Ensure the communication cable
shield is properly grounded to the outdoor unit chassis
only. Do not ground the outdoor unit to indoor units com-
munication cable at any other point. Wiring must comply
with all applicable local and national codes.
• Provide separate conduits for control wiring and power
wiring.
• Power and communications cables must not be routed
in the same conduit and must be routed in a manner that
keeps them a minimum of two (2) inches apart.
• Connect outdoor unit terminal IDU-A to the odd numbered
indoor unit terminal. Terminal “A” on the indoor units can
be tagged 3(A) or 5(A).
• Connect outdoor unit terminal IDU-B to indoor unit termi-
nal “B”. Terminal “B” on the indoor units can be tagged
3(B) or 5(B).
• Maximum allowed length of indoor unit communication
cable is 984 feet.
Figure 16: Communications Wiring Terminals (Appearance will Vary)..
GND
Fan Only/Cool/Heat Selector
Switch—Provides manual
override of microprocessor
selected mode of operation—
heating, cooling, or fan only
Central Control and
Building Automation System
Communication Bus
Connection—Connect LG
Central Controller and BMS
gateway products
Indoor Unit(s)—Communication
Bus Connection
Not used with Multi V S
Three-Phase
12V
Power source for
selected controllers
Ground
ODU B
DRY 2
DRY1
Cen. A
Cen. B
IDU A
IDU B
ODU A
• Ground wiring is required to prevent accidental electri-
cal shock during current leakage.
Do not connect the
ground line to the pipes.
• Install a main shutoff switch that interrupts all power sourc-
es simultaneously.
• If the system operates in reversed phase, it will break the
compressors and other components.
• If there is a possibility of reversed phase, phase loss, mo-
mentary blackout, or the power goes on and off while the
system is operating, install a field-supplied phase loss pro-
tection circuit. Operating the system in reverse phase will
break the compressor and other unit components.
• The GND terminal at the main PCB is a negative terminal for
dry contact, not a ground.
• Ground wiring is required to prevent communication problems from
electrical noise and motor current leakage.
• Make sure that the terminal numbers match (A to A, B to B).
• Communication cable between outdoor unit to indoor units must
be 18 AWG, 2-conductor, twisted, stranded, shielded. Ensure the
communication cable shield is properly grounded to the outdoor
unit chassis only. Do not ground the outdoor unit to indoor units
communication cable at any other point. Wiring must comply with all
applicable local and national codes.
• Maintain polarity throughout the communication network.
Figure 17: Multi V S Three-Phase ARUN072BSS5 / ARUN096BSS5
Electrical Component Location.
Main PCB
Terminal Block