Multi F Engineering Manual

FOUR-WAY VAHU INDOOR UNITS
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Four-way Vertical-Horizontal Air
Handing Indoor Unit
General
All LG indoor units are factory assembled, wired, piped, and pro-
vided with a control circuit board, fan, and motor. Vertical-Horizontal
Air Handling units are designed for high-speed air volume against an
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to accept field-installed ductwork that cannot exceed the external
static pressure limit of the unit.
Coil
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mechanically bonded to copper tubing. Each unit has a minimum of
two rows of coils, which are pressure tested at the factory. Each unit is
provided with a factory installed condensate drain pan below the coil.
Refrigerant System
System is designed for use with R410A refrigerant. The refrigeration
circuit is pressure-tested at the factory and shipped with a holding
charge of helium gas. Refrigerant pipe connections are 45° flare,
and all refrigerant lines from the outdoor unit to the indoor units must
be field insulated.
Electrical
Each indoor unit is designed to operate using 208–230/60/1 power
with voltage variances of ±10%.
Casing
The casing is designed to mount fully concealed behind a wall
or above a finished ceiling. Casing is manufactured of 22-gauge
precoated metal and finished with a high-gloss baked enamel finish.
Cold surfaces of the unit are covered internally with 1/2-inch polysty-
rene fiber insulation; inside surface of the pan assembly door access
panel is treated with 1/2-inch polystyrene fiber insulation, encapsu-
lated on both sides. The access panel is sealed along the edges with
reinforced foil-faced covering, all access panels also have gasket
seals to minimize air leaks.
The vertical-horizontal air handling unit can operate in one of four
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tal left discharge, or horizontal right discharge. Vertical downflow
operation requires an optional conversion kit. In the vertical position,
the unit has an opening for supply air from top (or bottom) with a
dedicated bottom (or top) vertical return. In the horizontal position,
supply air is from the left (or right) end with the return air from the
right (or left) end. Unit can also accept an internal, optional LG
electrical strip heater.
Fan Assembly and
Control
The units have an integral fan
assembly consisting of galva-
nized steel housing and a forward
curve fan wheel. The fan motor
is a brushless digitally controlled
(BLDC) motor with permanently
lubricated and sealed ball bear-
ings. The fan / motor assembly is
mounted on vibration-attenuating
rubber grommets. Fan speed is
controlled using a microproces-
sor-based direct digital control
algorithm. The indoor fan has Low,
Med, High, and Auto settings for
Cooling mode; and has Low, Med,
High, and Auto settings for Heat-
ing mode. Each of the settings can
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setting (RPM / ESP). The Auto
setting adjusts the fan speed to
most effectively achieve setpoint.
Filter Assembly
The unit comes with a filter rack sized to hold a field-provided 16” x
20” x 1” (NJ frame) or 24” x 20” x 1” (NK frame) filter cartridge. The
filter rack has a guide to assist in centering the filters, and can be
accessed from the front.
Microprocessor Control
The indoor unit is provided with an integrated control panel to com-
municate with the outdoor unit. All unit operation parameters are
stored in non-volatile memory resident on the unit microprocessor.
The microprocessor controls space temperature through using the
value provided by temperature sensors within the indoor unit. A
field-supplied communication cable must be installed to connect the
indoor unit(s) to the outdoor unit.
Controls
The indoor unit controller of choice must be ordered separately.
Communication between the indoor units and the outdoor unit is ac-
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/ communication cable. The indoor unit has a built-in dry contact for a
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able as an additional accessory for use with LG’s Smart ThinQ app on
a smart device.
Condensate
The unit is designed for gravity draining of condensate.
• Inverter (Variable speed fan)
• Control lock function
• Auto operation
• Dehumidifying function
• Two thermistor control
• Group control
• External static pressure control
• Self-diagnostics function
• Built-in dry contact for third party
thermostat
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Features
)LJXUH Multi F Vertical-Horizontal
Air Handling Indoor Unit.
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158 | VERTICAL-HORIZONTA L
Multi F and Multi F MAX Indoor Unit Engineering Manual
MULTI
F
MAX
MULTI
F