LG MULTI V ARNU363DDA4 Installation Manual page 44

ELECTRICAL
Communication Cable Specifications
Communication Cable Specifications From Outdoor Unit to RTU / Indoor
Units / Heat Recovery Units
• Communication cable from Main Outdoor Unit to RTU / Indoor Units / Heat Recovery Units is to be LG supplied or field supplied 18 AWG,
2-conductor, twisted, stranded, shielded. Ensure the communication cable shield is properly grounded to the Main Outdoor Unit chassis
only. Do not ground the Outdoor Unit to Indoor Units / Heat Recovery Units communication cable at any other point. Wiring must comply
with all applicable local and national codes.
• Cable shields between the connected devices must be tied together and continuous from the Main outdoor unit to the last component con-
nected and insulated to prevent grounding against the RTU/ IDU / HRU electrical enclosures.
• Start the communication cable at the main outdoor unit and route to the indoor units / heat recovery units in a daisy chain configuration.
Do not install in a starburst configuration.
• RTU / Indoor Unit / Heat Recovery Unit Communication Bus: The communication terminals are labeled differently among the indoor units,
depending on type (currently for indoor units: A / B, 3[A] / 4[B], or 3 / 4; for heat recovery units: A / B). Refer to the wiring diagram schematic
found in the indoor unit itself, or to the indoor unit wiring diagrams in the Engineering Manuals for more information. Match IDU A and B
terminals on outdoor unit to A (3) and B (4) terminals on indoor units / heat recovery units.
• Insulation as required by NEC and local codes.
• Rated for continuous exposure of temperatures up to 140°F.
• Maximum allowable communication cable length is 3,281 feet.
• Never splice communication cable.
• Ground wiring is required to prevent accidental electrical shock during current leakage, communication problems from electrical noise, and
motor current leakage. Do not connect the ground line to the pipes. There is risk of fire, electric shock, explosion, physical injury or
death.
• Never ground the shield of the communications cable to the indoor unit frame or other grounded entities of the building. Inadequate
connections will generate heat, cause a fire, and physical injury or death.
• Always verify the communication cable is connected to a communications terminal on the outdoor unit(s).
power to the communication cable connection. If contact is made, the PCBs will be damaged.
• Never use a common multiple-core communications cable. Each communications bus must be provided a separate cable (i.e.,
between outdoor unit(s) and indoor units, outdoor units and central controller(s). If communications cables of separate systems are wired
using a common multiple-core cable, it will result in a poor communications signal and unacceptable system operation.
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Due to our policy of continuous product innovation, some specifications may change without notification.
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Never apply line voltage