LG Multi V Water V ARWM072CAS5 Engineering Manual page 35

PIPING LIMITATIONS
For Systems Designed for Heat Recovery Configuration
Following pages present Multi V Water V piping limitations and are for illustrative purposes only. Designers MUST use LATS when designing LG VRF
systems.
Table 35: Piping Limitations for Heat Recovery Operation.
Total pipe length
Length
A + ΣB + ΣC ≤ 1,640 feet
ℓ
≤131 feet (295 feet conditional application)
Elevation differential (Water Source Unit ↔ Indoor Unit)
Elevation 1
Elevation differential (Indoor Unit ↔ Indoor Unit) [IDUs connected to separate HRUs which are parallel (Y-branch) connected.]
Elevation 2
Elevation differential (Indoor Unit ↔ Connected HRU or Series Connected HRU]
Elevation 3
Elevation differential (Indoor Unit ↔ Indoor Unit [connected to same Heat Recovery Unit])
Elevation 4
Elevation differential (Highest WSU ↔ Lowest WSU unit)
Elevation 5
Distance between WSU to WSU
Distance between fittings and Indoor Unit
Distance between fittings and Y-branches / Headers
Distance between two Y-branches / Headers
Height differential between two Heat Recovery Units if installed with a Y-branch
Height differential between two series-piped Heat Recovery Units
Maximum number of Heat Recovery Units per system
Assume equivalent pipe length of Y-branch is 1.6 feet, and equivalent pipe length of header is 3.3 feet.
1
For Heat Recovery Unit information, refer to the applicable Engineering Manual on www.lghvac.com.
© LG Electronics Canada, Inc., North York, ON Canada. All rights reserved. "LG" is a registered trademark of LG Corp.
64 | LIMITS / PLACEMENT
Longest actual pipe length Equivalent pipe length
≤656 feet ≤738 feet
Longest pipe length after first branch
Height ≤164 feet
Height ≤131 feet
Height ≤49 feet
Height ≤49 feet
Height ≤16 feet
≤33 feet
≥20 inches
≥20 inches
≥20 inches
≤98 feet
≤16 feet
16
.
Following pages present Multi V Water V piping limitations and are for illustrative purposes only. Designers MUST use LATS when designing LG VRF
systems.
Example of Pipe Sizing When Installing a Heat Recovery System
1
Example: Triple-frame system,
four (4) heat recovery units, one
(1) header, and twelve (12) indoor
units connected
WSU: Water Source Unit
HRU: Heat Recovery Unit
IDU: Indoor Unit
A: Main Pipe from Water Source Unit
to First Y-branch.
B: HRU to HRU, Y-branch to HRU, HRU
to Header, or Y-branch to Y-branch.
C: Heat Recovery Unit / Header to
Indoor Unit.
• Always reference the LATS Multi V
software report.
• Largest capacity WSU must be the
master in a multi-frame system.
• Master WSU capacity must be greater
than or equal to the slave1 WSU
capacity, and, where applicable, slave1
WSU capacity must be greater than or
equal to the slave2 WSU capacity.
• Connection piping from branch to branch cannot exceed the main pipe diameter (A) used by the water source unit.
• Install the header branches or heat recovery units so that the pipe distances between the between the connected indoor units are mini-
mized. Large differences in pipe distances can cause indoor unit performances to fluctuate.
• Y-branches and other header branches cannot be installed downstream of the initial header branch.
• Total capacity of indoor units in series connection of heat recovery units ≤192,400 Btu/h.
• If large capacity indoor units (>12,000 Btu/h with piping sizes >5/8Ø / 3/8Ø) are installed, the valve group setting must be used. (Refer to
the PCB of the heat recovery unit for the valve group control setting.)
© LG Electronics Canada, Inc., North York, ON Canada. All rights reserved. "LG" is a registered trademark of LG Corp.
PIPING LIMITATIONS
For Systems Designed for Heat Recovery Configuration
Figure 28: Heat Recovery Triple-Frame Connections.
S lav e 2 WS U
S lav e 1 WS U
M aster WS U
E lev ation 5
≤16 ft
M ulti-Frame
Connector
A
Closest
Y -branch ( first)
IDU
C
B
IDU
C
B
H RU
Y -branch ( second)
C
B
IDU
H RU
C
C
B
IDU
H RU
IDU
IDU
C
C
IDU
IDU
Y -branch
To WS U
To indoor units
B
H RU
C
C
B
H eader
Brazed
cap
x
C C C
Farthest
IDU IDU IDU
IDU
LIMITS / PLACEMENT | 65