30 | CEILING SUSPENDED
MUL
TI V Floor
, Suspended, Convertible Indoor Unit Engineering Manual
Due to our policy of continuous product innovation, some specifications may change without notification.
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LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. “LG” is a registered trademark of LG Corp.
CEILING SUSPENDED
Mechanical Specifications
Casing
The case is designed to mount against the ceiling surface in a
horizontal supply air configuration. The return air is from the bottom
and supply air is from a single slot on the front of the unit. The unit is
manufactured using a coated metal frame covered with an off-white
ABS architectural polymeric resin exterior case. Cold surfaces are
covered with a coated polystyrene insulating material.
Fan Assembly and Control
The unit has a single, direct driven, Sirocco fan made of high
strength ABS HR-2407 polymeric resin. The fan motor is a Brushless
Digitally-Controlled (BLDC) design with permanently lubricated and
sealed ball bearings. The fan/motor assembly is mounted on vibra-
tion attenuating rubber grommets. The fan speed is controlled using
a microprocessor-based direct digital control algorithm that provides
a minimum of three pre-programmed fan speeds in the Heating and
Fan Only modes and four speeds in the Cooling mode. Fan settings
are high, medium, and low. The fourth speed in the Cooling mode
is a super high setting that runs for 30 minutes at high fan speed.
A chaos wind setting provides random change in fan speed. The
fan speed algorithm provides a field selectable fixed or auto-speed
setting that changes fan speed based on the difference between
controller set-point and space temperature.
Air Filter
Return air is filtered with a removable, washable filter. Access to the
filter media is through a hinged, spring clip (screwless) return air
grille located on the bottom of the unit.
Airflow Guide Vanes
The supply air opening has a single directional slot diffuser with an
oscillating motorized guide vane designed to change the angle
airflow is supplied. The supply air range of motion is 40° in an up
/ down direction with the capability of locking the valve in a fixed
position. Manually adjustable guide vanes are provided to set the
airflow supply air direction from side-to-side.
Microprocessor Controls
The unit is provided with an integrated microprocessor-based con-
troller. The controller is capable of performing functions necessary
to operate the system without the use of a wall-mounted controller.
A temperature thermistor is factory-mounted in the return air stream.
All unit operation parameters, excluding the operating schedule, are
stored in non-volatile memory resident on the unit microprocessor.
Operating schedules are stored in select models of the optional,
wall-mounted, local or central controller. The field-supplied commu-
nication cable between the indoor unit(s) and outdoor unit is to be
a minimum of 18 AWG, 2 conductor, stranded, and shielded cable
(RS-485), terminated via screw terminals on the control boards. The
microprocessor control provides the following functions: self-diag-
nostics, auto restart following power restoration, test run, and will
operate the indoor unit using one of five operating modes:
1. Auto Changeover (Heat Recovery only)
2. Heating
3. Cooling
4. Dry
5. Fan Only
For Heat Recovery
systems the Auto
Changeover setting
automatically switch-
es between cooling
and heating modes
based on room tem-
perature conditions.
For Heat Pump
systems, heated or
cooled air delivery is dependent upon outdoor unit operating mode.
In Heating mode, the microprocessor control will activate the indoor
unit when indoor room temperature falls below setpoint temperature
and signals the outdoor unit to begin the heating cycle. The indoor
unit fan operation is delayed until coil pipe temperature reaches
76ºF. Significant airflow is generated when pipe temperature reaches
80°F. The unit is equipped with an infrared receiver designed to
communicate with an LG hand-held remote controller. Pluggable
connection sockets on the microprocessor circuit board accom-
modate various models of wall-mounted local controllers and/or a
wall-mounted remote temperature sensor. The unit microprocessor
is capable of accepting space temperature readings concurrently or
individually from either:
1. Wall-mounted wired controller(s)
2. Factory mounted return air thermistor or the optional wall-
mounted wired remote temperature sensor
A single indoor unit has the capability of being controlled by up to
two local wired controllers. The microprocessor controls space
temperature using the value provided by the temperature sensor
sensing a space temperature that is farthest away from the
temperature set-point. The microprocessor control provides a
Cooling mode test cycle that operates the unit in full Cooling mode
for 18 minutes without regard to space temperature. If the system
is provided with an optional wall-mounted or central controller, dis-
played diagnostic codes are specific, alpha numeric, and provide the
service technician with a reason for the code displayed.
Handling Condensate
The unit is designed for gravity draining of condensate. LG provides
a factory insulated flexible drain hose. If condensate lift/pumps are
needed for the application, they are to be field-provided.
Controls Features
• Auto changeover
(Heat Recovery only)
• Auto operation
• Auto restart
• Child lock
• Dual thermistor control
• Forced Operation
• Group control
• High ceiling
• Hot start
• Self diagnostics
• Sleep mode
• Timer (on / off)
• Weekly schedule
• Soft dry (dehumidification)
• Auto direction/swing (up / down)
• Manual control direction (left /
right)
• Fan speed control
• Chaos wind (random fan
speed)
• Jet cool (fast cooling)
