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PRE-COMMISSIONING
Indoor Unit Auto Addressing / Group Controlling Indoor Units
Troubleshooting a Failed Indoor Unit Auto Addressing Procedure
If the quantity of indoor units the auto addressing procedure found is incorrect, or the "88" never disappears from the display for the seven (7)
minutes, the auto address procedure has failed and a communications problem exists. If the Auto Address Procedure failed:
1. Verify ALL indoor unit ON/OFF buttons are in the OFF position (i.e., ON / OFF button NOT illuminated).
2. Check the terminations, polarity, and continuity of each conductor on the communications cable between the outdoor unit and the indoor
units. Verify the indoor unit to outdoor unit communications cable is wired correctly.
• Verify the conductor connected to the "3" (or "5" in the case of cassette frame codes TP, TN, TM) terminals on all indoor units and is
terminated on the outdoor unit terminal tagged IDU(A).
• In a similar fashion, verify the conductor connected to all indoor units on the "4" (or "6" in the case of cassette chassis codes TP, TN, TM)
terminals and is terminated on the outdoor unit terminal tagged IDU(B).
3. Verify the shield of the communications cable is grounded at the outdoor unit only. All segment shields should be spliced together at each
indoor unit and NOT grounded.
4. After repairing the communications cable, go to Step 9 of the Auto Addressing Procedure and repeat the process until successful: Press
and hold the red SW01C button for about five (5) seconds. Release when "88" appears on the SSD. After three (3) to seven (7) minutes,
the display will flash a number for about thirty (30) seconds indicating how many total indoor units the system successfully communicated
with.
5. This number should match the known installed number of indoor units if the auto addressing procedure was successful.
6. Upon completion of the auto addressing routine, the display will be blank and the system will be in standby waiting for another com-
mand.
7. Record the system address the outdoor unit assigned to each indoor unit by the auto address procedure in the column provided on the
Pre-commissioning Device Configuration Worksheet.
8. After recording the system addresses assigned to each device, open the outdoor unit disconnect. Remove the outdoor unit to indoor unit
communications cable from terminals IDU(A) and IDU(B). Protect conductors by placing electrical tape over the bare ends to prevent an
accidental compressor start from occurring before the LG trained commissioner arrives.
9. Close the disconnect to reapply power to the outdoor unit and energize the compressor crankcase heater. Once again, verify the outdoor
unit to indoor unit(s) communications cable is not connected to terminals IDU(A) and IDU(B) of the outdoor unit.
10. Replace the control panel cover.
Group Controlling Indoor Units
If any of the indoor units were specified to operate in unison, create a group control communications circuit between the indoor units using
field wiring (with indoor units that have SIG - 12V - GND [Comm.] terminals), or a group control cable kit (with indoor units that have CN-RE-
MO).
1. Before proceeding with group control cable terminations, verify power is OFF at all applicable indoor units.
2. Identify which indoor unit will be the "Master" unit of the group. If not already recorded, record the "Master" and the "Slave" identity
assignment to each indoor unit in the group on the Pre-commissioning Device Configuration Worksheet.
3. SIG - 12V - GND [Comm.] Terminal Procedure
• From the controller to the master indoor unit, use 22 AWG, 3-conductor, twisted, stranded, unshielded.
• From the master indoor unit to the slave indoor unit(s), daisy chain using 22 AWG, 3-conductor, twisted, stranded, unshielded
(
Do not attach wire to 12VDC terminal to the slave indoor units). All wiring must comply with all applicable local and national codes.
• All wiring must comply with all applicable local and national codes.
4. CN-REMO Termination Procedure:
• Starting with the master indoor unit, plug in the male end of the pigtail cable into the CN-REMO socket. At the last slave indoor unit in
the group, a pigtail cable is not required. Plug the male end of the extension cable coming from the previous indoor unit into the CN-RE-
MO socket.
• Plug the Y-cable into the pigtail at each indoor unit except for the last slave indoor unit in the group where no Y-cable cable will be
needed.
• Connect two extension cable segments to each "Y" cable except for the "Y" cable connected to the master indoor unit. At the master
indoor unit, connect one extension cable and the communications cable from the zone controller to the Y-cable.
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Due to our policy of continuous product innovation, some specifications may change without notification.
©LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. "LG" is a registered trademark of LG Corp.
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