36
MUL
T
I F / MUL
TI F MAX Outdoor Unit Installation Manual
Due to our policy of continuous product innovation, some specifications may change without notification.
©LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. “LG” is a registered trademark of LG Corp.
MULTI
F
MAX
MULTI
F
Using Refrigerant Components
Field-supplied elbows are allowed as long as they are designed for
use with R410A refrigerant. The designer, however, must be cau-
tious with the quantity and size of fittings used, and must account
for the additional pressure losses in equivalent pipe length calcula-
tion for each branch. The equivalent pipe length of each elbow must
be added to each pipe segment.
Table 11: Equivalent Piping Length for Elbows, Y-branches, and Branch
Distribution Units.
5()5,*(5$176$)(7<67$1'$5'6
DEVICE CONNECTION LIMITATIONS
Component
Size (Inches)
1/4 3/8 1/2 5/8 3/4
Elbow (ft.)
0.5 0.6 0.7 0.8 1.2
Y-Branch Kit
(ft., Multi F MAX systems only)
1
1.6
Branch Distribution Unit
(ft., Multi F MAX systems only)
8.2
1
.LWFRQWDLQVWZR<EUDQFKHVRQHIRUOLTXLGDQGRQHIRUYDSRU
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).
Ȉ$0DLQ3LSH
Ȉ%%UDQFK3LSH%UDQFK'LVWULEXWLRQ8QLW>V@WR,QGRRU8QLW>V@
B
A
h2 ≤ 49.2 feet
A
h3 ≤ 32.8 feet
h4 ≤ 49.2 feet
h1 ≤ 98.4 feet
BDU
Y-Branch
BDU
IDU
A
ODU
IDU
IDU
IDU
IDU
IDU
IDU
B
B
B
B
B
B
Pipe Length
(ELF = Equivalent
Length of pipe in
Feet)
7RWDOSLSLQJOHQJWKȉ$ȉ%
IHHW
Main pipe (Outdoor Unit to
Branch Distribution Units:
ȉ$
Minimum
9.8 feet
Maximum
IHHW
7RWDOEUDQFKSLSLQJOHQJWKȉ%
IHHW
Branch pipe (Branch
Distribution Units to Indoor
Units: B)
Minimum
10 feet
Maximum
IHHW
Elevation Differential
(All Elevation
Limitations are
Measured in Actual
Feet)
If outdoor unit is above or below indoor unit (h1)
IHHW
Between the farthest two indoor units (h2)
IHHW
Between branch distribution unit and farthest
connected indoor unit(s) (h3)
IHHW
Between branch distribution units (h4)
IHHW
Max. Combination of
IDUs
LMU480HV = 65,000
LMU540HV = 73,000 LMU600HV = 81,000
Piping
Main Pipe A (inch)
Branch Pipe B
Liquid
Ø3/8
Depends on the size
of the indoor unit piping
Gas
Ø3/4
Multi F MAX System Example with Two Branch Distribution Units
Multi F MAX Outdoor Unit Piping Length and Elevation Limitations
Table 12: Multi F MAX Refrigerant Piping System Limitations.
h1
C
Branch Pipe
Main Pipe
BD Unit
BD Unit
A
B
h2
Figure 25: Multi F MAX Refrigerant Piping
System Limitations.
Table 13: Multi F MAX Piping Sizes.