LG MULTI F Engineering Manual page 38

MULTI F MAX WITH LGRED BD UNIT
Branch Distribution Unit
General
Branch distribution units are designed for use with LG Multi F MAX with LGRED
(LMU360HHV and LMU420HHV) outdoor units, and are internally piped, wired,
assembled and run-tested at the factory. The branch distribution unit is used as
an intermediate refrigerant control device between the outdoor unit and the indoor
units to effectively and efficiently control the heating or cooling operation of the
system through the use of electronic expansion valves.
Refrigerant System
System is designed for use with R410A refrigerant. All refrigerant lines from the
outdoor unit to the branch distribution unit, and from the branch distribution unit to
the indoor units, must be field insulated. The units may be connected to optional
field-supplied and field-installed isolation valves for servicing without evacuating
the entire system.
Piping Capabilities
Maximum piping length from the branch distribution unit to the indoor unit is 49.2
equivalent feet. Maximum elevation difference between branch distribution unit
and indoor unit is 32.8 feet. Maximum elevation difference between two parallel
branch distribution units is 49.2 feet.
Electrical
Each branch distribution 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 above a finished ceiling, is manufactured of galvanized steel plate, and is internally
insulated. Branch distribution units do not require a condensate drain.
Port Assembly
Branch distribution units have a two-pipe system consisting of one vapor pipe and one liquid pipe. Units are available in a choice of two
(PMBD3620), three (PMBD3630) or four ports (PMBD3640 and PMBD3641); branch distribution units include two, two-positioned solenoid
valves per port. Each port for PMBD3620, PMBD3630, and PMBD3640 units connects to one indoor unit for a maximum nominal capacity of
24,000 Btu/h. For PMBD3641 units, ports A, B, C each connect to one indoor unit for a maximum nominal capacity of 24,000 Btu/h; port D
connects to one indoor unit for a nominal capacity of 36,000 Btu/h. Maximum nominal capacity per branch distribution unit is 73,000 Btu/h.
Two branch distribution units can be piped in parallel using accessory Y-branch kit PMBL5620.
Controls
The unit is provided with factory-installed control boards and an integral microprocessor to communicate with the main control board in the
outdoor unit. All power wiring / communication cable to be minimum 16 AWG from the outdoor unit to the branch distribution unit, and 18
AWG from the branch distribution unit to the indoor unit, stranded, shielded or unshielded (if shielded, it must be grounded to the chassis of
the outdoor unit only), and must comply with applicable local and national codes.
38 | MF MAX WITH LGRED BD UNIT
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F
MULTI MAX
Figure 22: PMBD3620 Two-Port Branch Distribution Unit.
Figure 23: PMBD3630 Three-Port Branch Distribution Unit.
Figure 24: PMBD3640 and PMBD3641 Four-Port Branch
Distribution Unit.
WITH