Multi F Engineering Manual
Table Of Contents
'XHWRRXUSROLF\RIFRQWLQXRXVSURGXFWLQQRYDWLRQVRPHVSHFL¿FDWLRQVPD\FKDQJHZLWKRXWQRWL¿FDWLRQ
©/*(OHFWURQLFV86$,QF(QJOHZRRG&OLIIV1-$OOULJKWVUHVHUYHG³/*´LVDUHJLVWHUHGWUDGHPDUNRI/*&RUS
14 | MULTI F OUTDOOR UNIT
Multi F and Multi F MAX Heat Pump System Engineering Manual
MULTI
F
MAX
MULTI
F
0HFKDQLFDO6SHFL¿FDWLRQV
MULTI F OUTDOOR UNIT
Multi F Heat Pump Condensing Units
General
A Multi F multi-zone system is comprised of one heat pump outdoor
unit connected to two, three, or four indoor units using a shared
refrigerant piping circuit between the outdoor unit and each indoor
unit, and includes integrated controls supplied by LG. The outdoor
unit is internally assembled, wired, and piped from the factory; all LG
components are manufactured in a facility registered to ISO 9001
and ISO 14001, set by the International Organization for Standard-
ization (ISO). The LG Multi F multi zone heat pump system compo-
nents comply with Underwriters Laboratories (UL) 1995 Heating and
Cooling Equipment Standard for Safety. The units are certified to
AHRI 210 / 240.
Temperature Ranges
The heat pump outdoor units are capable of continuous operation in
cooling mode from 14°F to +118°F ambient dry bulb (installing an
optional Low Ambient Wind Baffle Kit will allow continuous operation
down to -4°F in cooling mode for Multi F systems). The heat pump
outdoor units are capable of continuous operation in heating mode
from -4°F to +64°F ambient wet bulb without additional low ambient
controls, and intermittent operation from -9°F to +64°F .
Frame
The Multi F condensing unit case is constructed from pre-coated
metal that has been tested in accordance with ASTM B-117 salt
spray procedure for a minimum of 1,000 hours. Case has a remov-
able front panel to allow access to major components and control
devices, and legs to secure the unit during installation.
Refrigerant System
Multi F systems have a shared refrigerant circuit field piped to
multiple (ducted, non-ducted or mixed) indoor units to effectively and
efficiently control the heating or cooling operation of the multi zone
system. All refrigerant lines from the outdoor unit to the indoor units
are field-installed and must be insulated separately.
All Multi F systems use R410A refrigerant. The outdoor units are
equipped with a refrigerant strainer, check valves, oil separator,
accumulator, four-way reversing valve, electronic expansion valve(s)
(EEV), high side and low side refrigerant charging ports, and a
service port. Each outdoor unit also includes sensors for suction
temperature, discharge temperature, high-pressure, low-pressure,
heat exchanger temperature, and outdoor temperature conditions.
Refrigeration Oil Control
The outdoor units have an oil separator to separate oil mixed with
the refrigerant gas during compression and return oil to the com-
pressor. The outdoor units also have an oil injection mechanism to
ensure a consistent film of oil on all moving compressor parts at low
speed.
Compressor
Multi F condensing units are equipped with one hermetically sealed,
digitally controlled, inverter driven twin-rotary compressor that
includes Teflon™ coated bearings. The inverter motor is capable of
providing a modulation range of 10Hz to 70Hz (cooling) and 10Hz
to 99Hz (heating) (for LMU183-243HV models), and 10Hz to 80Hz
(cooling) and 10Hz to 100Hz (heating) (for LMU303-363HV models)
with control in 1Hz increments. The compressor is protected with
phase-reversal protection, uses a factory-charge of Polyvinyl Ether
(PVE) oil, and is mounted to avoid the transmission of vibration.
Fan and Motors
Each outdoor unit includes one direct drive variable speed propeller
fan with Brushless Digitally Controlled (BLDC) motor with a horizon-
tal air discharge. Fan blades are statically and dynamically balanced
propeller fans made of durable Acrylonitrile Butadiene Styrene (ABS)
plastic, and include a raised fan guard to limit contact with moving
parts. The motors have inherent overload protection, permanently
lubricated bearings, and a maximum speed up to 840 rpm (for
LMU183-243HV models), or 750 rpm (for LMU303-363HV models).
All Multi F outdoor units have a horizontal discharge airflow.
Outdoor Unit Coil
The outdoor unit coils are factory-built of aluminum fins mechani-
cally bonded on copper tubing. Coils have a minimum of two rows, a
minimum of 14 fins per inch, and have been factory pressure-tested.
Coil fins also have a factory applied corrosion-resistant GoldFin™
material with hydrophilic coating that has been tested in accordance
with ASTM B-117 salt spray test procedure for a minimum of 1,000
hours.
Electrical
All Multi F outdoor units have 208/230V, 1 phase, 60Hz electrical
power capable of operating within ±10% of the rated voltage.
Controls
Factory installed microprocessor controls in the outdoor unit and
indoor units perform functions to efficiently operate the multi- zone
system. System wiring must be installed in a tree configuration from
outdoor unit to indoor units through four conductor power/transmis-
sion cable. The system is capable of performing continuous opera-
tion, even when power is turned off to an individual indoor unit.
Figure 4: Multi F LMU183HV and
LMU243HV Outdoor Units.
Figure 5: Multi F LMU303HV and
LMU363HV Outdoor Units.