Multi F Engineering Manual

TWO-WAY VAHU INDOOR UNITS
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Two-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 two-way vertical-horizontal air handling unit can operate in one
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horizontal (left) end discharge. Supply air is drawn from the top, and
there is a dedicated bottom vertical return. Unit is also designed to
accept an internal, optional LG electrical strip heater.
Fan Assembly and Control
The units have an integral fan assembly consisting of galvanized
steel housing and a forward
curve fan wheel. The fan
motor is a brushless digitally
controlled (BLDC) motor with
permanently lubricated and
sealed ball bearings. The fan
/ motor assembly is mounted
on vibration-attenuating rub-
ber grommets. Fan speed is
controlled using a micropro-
cessor-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
Heating mode. Each of the
settings can be field-adjusted
from the factory setting (RPM
/ ESP). The Auto setting ad-
justs the fan speed to most
effectively achieve setpoint.
Filter Assembly
The unit includes a filter rack that can accept a field-supplied 16” x
20” x 1” filter cartridge. The filter rack has a guide to assist in center-
ing 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.
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
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Features
)LJXUH Multi F Vertical-Horizontal
Air Handling Indoor Unit.
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138 | VERTICAL-HORIZONTAL
Multi F and Multi F MAX Indoor Unit Engineering Manual
MULTI
F
MAX
MULTI
F