8 | FLOOR STANDING
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.
FLOOR STANDING
Mechanical Specifications
Casing
Cased
The case is designed to be free standing on the floor against a
vertical surface. The backplane of the unit allows secure attachment
of the unit to a vertical surface. Supply air is vertical from the top of
the unit with a bottom front return through a toe slot at floor level.
The supply air opening is covered with an architectural grille. The
unit is manufactured using coated metal with an off-white ABS
architectural polymeric resin exterior case. Cold surfaces are
covered with a coated polystyrene insulating material. Flip open
controller access doors cover the controller mounting bays located
on both ends of the top panel. A polymeric resin coated metal safety
grille is provided behind the removable filters located in the toe
space to prevent reach access to the fan wheel.
Uncased
The unit case is designed to be concealed in a field-provided
architectural enclosure. The unit case is manufactured using coated
metal. Cold surfaces are covered with a coated polystyrene insu-
lating material. The back plane of the unit has two side mounting
flanges with bolt holes for hanging the unit on a vertical wall near the
floor. Airflow is vertical from the bottom to the top. A polymeric resin
coated metal safety grille is provided behind the removable filters
located at the return air opening to prevent reach access to the fan
wheels.
Fan Assembly and Control
7–15 MBh
The unit has three Sirocco fans mounted on a common shaft and
made of high strength ABS HT-700 polymeric resin. The fan shaft is
directly driven by a single digitally-controlled inverter fan motor.
18–24 MBh
The unit has two independent fan assemblies consisting of two mo-
tors and four fans. Each assembly consists of two Sirocco fans made
of high strength ABS HT-700 polymeric resin. Each pair of fans are
mounted on a common shaft and driven directly by a single digitally
controlled inverter motor.
Fan Motors
The fan motors are 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 in vibration attenuating rubber grommets. The
fan impeller is statically and dynamically balanced. The fan speed is
controlled using a microprocessor-based direct digital control algo-
rithm 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 or auto-speed setting that
adjusts fan speed to simulate natural airflow.
Air Filter
Return air is filtered using two (2) removable, washable filters with
anti-fungal treatment on the 7-15 MBh models and three (3) remov-
able, washable filters with anti-fungal treatment on the 18-24 MBh
models. Access to the filter media is from the return air toe slot
located on the front of the unit without removing unit panels.
Microprocessor Control
The unit is provided with an integrated microprocessor-based
controller. A temperature thermistor is factory-mounted in the return
air stream. The controller is capable of performing functions
necessary to operate the system without the use of a separate unit
or wall-mounted controller. All unit operation parameters, excluding
the operation schedule, are stored in non-volatile memory resident
on the unit microprocessor. Operating schedules are stored in select
models of the optional unit or wall-mounted, local or central
controller. 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), terminated via
screw terminals on the control boards. The microprocessor control
provides the following functions: auto addressing, self-diagnostics,
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 automat-
ically switches between cooling and heating modes based on room
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 the indoor
unit when indoor room temperature falls below set-point 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. In lieu of factory return air thermistor, screw terminals on the
microprocessor circuit board accommodate various models of wall
Cased
Uncased
