42 | CONVERTIBLE
MUL
TI V Floor
, Suspended, Convertible Indoor Unit Engineering Manual
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.
CONVERTIBLE SURFACE MOUNTED
Mechanical Specifications
Casing
The case is designed to mount against the ceiling surface in a
horizontal discharge configuration or on a wall in a vertical discharge
configuration. When mounted against the ceiling surface, the return
air is from the bottom of the unit. When mounted on a wall, the
return air is from the front surface of the unit. The unit is manufac-
tured using a coated metal frame covered with an off-white ABS ar-
chitectural 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 front/bottom of the unit.
Airflow Guide Vanes
The discharge opening has a single directional slot diffuser with
an oscillating motorized guide vane designed to change the angle
airflow is discharged. The discharge range of motion is 40° in an
up/down direction with the capability of locking the vane in a fixed
position. Manually adjustable guide vanes are provided to set the
airflow discharge 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 Change-
over setting automatically
switches between cooling
and heating modes based
on room temperature
conditions.
For Heat Pump systems,
heated or cooled air de-
livery 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 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. In lieu of
factory return air thermistor, pluggable connection sockets on
the microprocessor circuit board accommodate 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 tem-
perature 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 for 18 minutes without regard to space
temperature. If the system is provided with an optional wall-mount-
ed or central controller, displayed diagnostic codes are specific,
alphanumeric, 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
• External static pressure control
• Hot start
• Self diagnostics
• Timer (on / off)
• Weekly schedule
• Soft dry (dehumidification)
