LG Multi V Series Engineering Manual page 154

VERTICAL / HORIZONTAL AIR HANDLER
Mechanical Specifications
Casing
The unit is designed to operate in the vertical up flow configuration
or horizontal left end supply air. Return air opening is on the bottom
in the vertical position or right end in the horizontal position. Return
air plenum sub-base is to be field-provided. The supply air con-
nection is male flange. The unit case is made of 22-gauge coated
metal and the external surfaces are finished with a high gloss baked
enamel finish. Finish color is "morning fog" (medium beige). Cold
surfaces are galvanized steel. The cold surfaces of the case are in-
ternally insulated with ½ inch foil faced, polystyrene fiber insulation.
The inside surface of the fan assembly door access panel is treated
with ½ inch polystyrene fiber insulation, encapsulated on both sides,
and sealed along the edges with a reinforced foil-faced covering to
prevent deterioration caused by panel removal. All access panels are
provided with gasket seals to minimize air leakage. The unit case is
designed to accept an internal, optional, LG electric strip heater. The
unit bears the ETL label. Unit breaker, fuses, and / or disconnect are
provided by others.
Fan Assembly and Control
The indoor unit has an integral fan assembly consisting of a
galvanized steel housing and a forward-curved fan wheel. The direct
drive fan/motor assembly is mounted on rubber grommets isolat-
ing the rotating assembly from the fan housing. The fan motor is a
Brushless Digitally-Controlled design (BLDC), having 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. Fan speed is controlled using
a microprocessor-based direct digital control algorithm that provides
a minimum of 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 and DIP switch
settings will allow the fan to run constantly during defrost or oil return
modes. Each setting can be field adjusted from the factory setting
(RPM/ESP). The setting provides delivery of the high speed air
volume against an external static pressure of up to 1.0 in-wg.
Air Filter
The unit comes with a filter rack capable of accepting a field-
provided 16" x 20" x 1" (NJ chassis) or 24" x 20" x 1" (NK chassis)
filter cartridge. The filter rack is equipped with guides that keep the
filter centered in the rack. Filter service access is from the front of
the unit without removing the coil or fan area access panels. Filter
access door is provided with thumb screws that can be removed.
Optional Auxiliary Electric Heat Module(s)
LG optional electric heat modules are designed for field
installation in the reheat position. The electric heat module is
provided with heating elements, contractors, relays, high
temperature safety switch, and interconnecting control wiring har-
ness with a quick connect plug for easy connection to the air handler
154 | VAH
Due to our policy of continuous product innovation, some specifications may change without notification.
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control board. Auxiliary heat modules are
available in nominal
capacities of 3, 5, 8, 10, 15, and 20kW
at 230/60/1. Heating elements are
powered from a field provided separate
power source. 5 and 10 kW modules are
powered from a single power wire. The 15
and 20 kW modules are powered from two
power wires. Heating module breakers,
fuses, and / or disconnects are to be field
provided.
Electric Heat Module Controls
The electric heat module is capable of
operating at full capacity during system
defrost and oil return operations. When the air handler is operating
in the Cooling, Dry, or Fan Only modes, the electric heater operation
is locked out and unavailable. When the air handler is operating in
the Heating mode, the heater is field selectable to operate when the
room temperature is 2°F lower than set-point or manually if provided
with a start/stop signal from a third-party outside source.
Microprocessor Controls
The unit is equipped with an integrated microprocessor-based
controller capable of performing functions necessary to operate the
system without the use of a wall-mounted controller. A temperature
thermistor is mounted in the return air stream. All unit operating
parameters, excluding the operation schedule, are stored in non-vol-
atile memory resident on the unit microprocessor. Operating sched-
ules 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 (RS-485). The microprocessor
control provides the following functions: auto addressing, self-
diagnostics, auto restart following power restoration, and will operate
the indoor unit using one of the following 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 does not begin fan
operation until coil pipe temperature reaches 76ºF. Significant
airflow is generated when pipe temperature reaches 80°F. A field-se-
lectable option maintains fan operation for 30 minutes following