LG Multi V ARNU093TUD4 Engineering Manual page 8

ONE-WAY CEILING CASSETTE
Mechanical Speci cations
Casing
The case is designed to mount recessed in the ceiling and has a
surface-mounted concentric grille on the bottom of the unit. The unit
case is manufactured with coated metal. Cold surfaces are covered
with a coated polystyrene insulating material. The case is provided
with metal ears designed to support the unit weight on four corners.
Ears have pre-punched holes designed to accept field-supplied
all-thread rod hangers.
Ventilation Air
The case has a factory designated cutout for the connection of a
field-supplied outside air duct and flange.
Architectural Filter/Grille
The ceiling cassette assembly is provided with an off-white ABS
polymeric resin architectural grille with a tapered trim edge and a
hinged, spring clip (screw-less) return air filter-grille door.
Fan Assembly and Control
The indoor unit has a single, direct-drive, cross-flow tangential
Sirocco fan made of high strength ABS GP-2305 polymeric resin.
The fan motor is a Brushless Digitally Controlled (BLDC) design with
permanently lubricated and sealed ball bearings. The fan motor in-
cludes 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 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
adjusts the fan speed to simulate natural airflow.
Air Filter
Return air is filtered with a removable, washable filter with anti-fungal
treatment. Plasma filter accessories are also available separately.
Airflow Guide Vanes
The architectural grille 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 40º in an
up/down direction with the capability of locking the vanes in a field
adjusted fixed position.
Microprocessor Controls
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
thermistor is factory-mounted in the return air stream. All unit
operation parameters, excluding the operation schedule, are stored
in non-volatile memory resident on the unit microprocessor.
8 | ONE-WAY ©
Operating schedules are stored in select models of the optional,
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 ca-
ble (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 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 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 wireless
remote controller. In lieu of wireless remote or factory return air
thermistor, screw terminals on the microprocessor circuit board ac-
commodate 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 or heating