LG PREMTC00U Owners & Installation Manual page 251

F
MULTI
F
MULTI MAX
The following are examples of manual pipe size calculations. Designers are highly encouraged to use LATS for Multi F systems.
Multi F MAX System with One Branch Distribution Unit
Example: LMU540HV outdoor unit with
four (4) indoor units, and one (1) branch
distribution unit connected.
oDu: outdoor unit.
iDu: indoor unit.
BDu: Branch Distribution unit.
a: Main Pipe.
B: Branch Pipe (Branch Distribution unit to
Indoor Unit[s]).
Multi F MAX System with Two Branch Distribution Units
Example: LMU540HV outdoor unit with
seven (7) indoor units, and two (2)
branch distribution units connected.
oDu: outdoor unit.
iDu: indoor unit.
BD: Branch Distribution unit(s).
ΣA: Main Pipe.
ΣB: Branch Pipe (Branch Distribution Unit[s] to
Indoor Unit[s]).
table 167: Multi f MaX outdoor unit Refrigerant Piping system Limitations.
Main pipe (outdoor unit to
Pipe Length
Branch Distribution Units: ΣA)
(eLf = equivalent
Length of pipe in feet)
Branch pipe (Branch Distribu-
tion units to indoor units: B)
if outdoor unit is above or below indoor unit (h1)
elevation Differential
(all elevation
Limitations are
Between branch distribution unit and farthest indoor
Measured in actual
feet)
ODU
h1 ≤ 98.4 feet
ODU
h4 ≤ 49.2 feet
h1 ≤ 98.4 feet
Total piping length (ΣA + ΣB)
Total branch piping length (ΣB)
Between the farthest two indoor units (h2)
unit(s) (h3)
Between branch distribution units (h4)
Due to our policy of continuous product innovation, some specifications may change without notification.
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REFRIGERAnT PIPInG DESIGn
BDU
A
h3 ≤ 32.8 feet
A
Y-Branch BDU
A
A
≤475.7 feet
Minimum 10 feet
Maximum
≤180.4 feet
≤295.3 feet
Minimum 10 feet
Maximum
≤49.2 feet
≤98.4 feet
≤42.9 feet
≤32.8 feet
≤42.9 feet
Design Guideline Summary
IDU
B
IDU
B
B
B
IDU
B
IDU
B
B
IDU
BDU
B
IDU
B
B
B
table 168: Multi f MaX Piping sizes.
Main Pipe a
Piping
(inch)
Liquid Ø3/8
of the indoor unit piping
gas Ø3/4
DeSiGn & PracticeS | 199
h2 ≤ 49.2 feet
IDU
IDU
h3 ≤ 32.8 feet
IDU
h2 ≤ 49.2 feet
IDU
IDU
Branch Pipe B
Depends on the size