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all-Mounted 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.
STANDARD WALL-MOUNTED
Mechanical Specifications
Casing
Units are designed to mount on a vertical surface and come com-
plete with an installation mounting guide and a separate hanging
bracket. The unit case is manufactured with coated metal. Cold
surfaces are covered with a coated polystyrene insulating material.
Finish
The unit case is manufactured using ABS polymeric resin and has a
pearl white finish.
Fan Assembly and Control
The unit has a single, direct-drive, crossflow tangential Sirocco fan
made of high strength ABS BSN-7530 polymeric resin. The fan motor
is a Brushless Digitally Controlled (BLDC) design with permanently
lubricated and sealed ball bearings. The fan motor includes thermal,
overcurrent and low RPM protection. The fan/motor assembly is
mounted on vibration attenuating rubber grommets. The fan impeller
is statically and dynamically balanced. The fan speed is controlled
using a microprocessor-based direct digital control algorithm that
provides a high fan speed in cooling thermal ON and low fan speed
in cooling thermal OFF, high fan speed in heating thermal ON and
fan off in heating thermal OFF. The fan speeds can be field adjusted
between low, medium, and high speeds. The fan speed algorithm
provides a field-selectable fixed-speed or auto-speed setting that
changes the fan speed to simulate natural airflow.
Air Filter
Return air is filtered with a removable, washable filter with anti-fun-
gal treatment. Filter access is from the front of the unit without the
use of tools.
Airflow Guide Vanes
5–15 MBh
The indoor unit is provided with a motorized oscillating guide vane
that automatically changes the direction of up-and-down airflow.
The indoor unit includes factory installed, manually adjustable guide
vanes that control the side-to-side direction of supplied airflow.
18-36 MBh
The indoor unit is provided with a motorized sweeping guide vane
that automatically changes the direction of airflow from side-to-side
and up-and-down.
Microprocessor Control
The unit is provided with an integrated microprocessor controller
capable of performing functions necessary to operate the system
without the use of a wall-mounted controller. A temperature thermis-
tor 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 controllers. The field-supplied communication 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), terminat-
ed via screw terminals on the control boards. The microprocessor
control provides the following functions: auto addressing, self-diag-
nostics, auto restart following power restoration, test run, and will
operate the indoor unit using one of five operation modes:
1. Auto Changeover (Heat Recovery only)
2. Heating
3. Cooling
4. Dry
5. Fan Only
For Heat Recovery systems the Auto Changeover setting automati-
cally switches control of the indoor unit between Cooling and Heating
modes based on space temperature 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 indoor unit
operation when the indoor room temperature falls below set-point
temperature. At which point, a signal is sent to the outdoor unit to
begin the heating cycle. The indoor unit fan operation is delayed until
coil pipe temperature reaches 76°F. Significant airflow is generated
when pipe temperature reaches 80°F. A field-selectable option
maintains fan operation for 30 minutes following cooling cycle
operations. The unit is equipped with an infrared receiver designed
to communicate with an LG wireless remote controller. In lieu of
wireless remote or factory return air thermistor, screw terminals on
the microprocessor circuit board accommodates various models of
wall-mounted local controllers. 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
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 or heating
mode test cycle that operates the unit for 18 minutes without regard
to the space temperature. If the system is provided with an optional
