48 | REFRIGERANT DESIGN
Single Zone Wall Mounted Extended Piping Engineering Manual
Due to our policy of continuous product innovation, some specications may change without notication.
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LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. “LG ” is a registered trademark of LG Corp.
INSTALLATION & LAYOUT BEST PRACTICES
Refrigerant Piping System Layout
Physical Pipe Length: Actual length of straight segment(s) of pipe.
Equivalent Pipe Length: Actual length of pipe plus equivalent lengths of long radius elbows, Y-branches, and valves.
1. Draft a one-line diagram of the proposed piping system connecting outdoor unit to indoor units. Follow the pipe limitations listed on the
previous page.
2. Calculate the physical length of each pipe segment and note it on the drawing.
3. Calculate the equivalent pipe length of each pipe segment.
Using Elbows
Field-supplied elbows are allowed as long as they are long radius and designed
for use with R410A refrigerant. The designer, however, should be cautious with
the quantity and size of fittings used, and must account for the additional pressure
losses in equivalent pipe length calculation. The equivalent pipe length of each
elbow must be added to each pipe segment. See the table for equivalent lengths.
Table 23: Equivalent Piping Length for Piping Components.
Definitions
Layout Procedure
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
Obstacles
When an obstacle, such as an I-beam or concrete T, is in the path
of the planned refrigerant pipe run, it is best practice to route the
pipe over the obstacle. If adequate space is not available to route
the insulated pipe over the obstacle, then route the pipe under the
obstacle. In either case, it is imperative the horizontal section of pipe
above or below the obstacle be a minimum of three (3) times greater
than the longest vertical rise (or fall) distance.
Figure 14: Installing Piping Above and Below an Obstacle
MINIMUM
MINIMUM
3X
X
3X
X
Field-Provided Isolation Ball Valves
LG maintains a neutral position on using isolation valves in VRF refrigerant piping systems. LG does not endorse any manufacturer of isola-
tion valves. It is recognized that installing isolation valves may simplify future maintenance requirements, and, if used, considerations should
be taken including, but not limited to, the following:
• Pressure drops for any component used, including isolation valves, must be known in equivalent pipe length and calculated into the total
and segment equivalent piping lengths and compared to product design limitations.
• In all cases, materials must be suitable for the application and any applicable codes, including, but not limited to, diameter and wall thick-
ness continuity per ACR standards.
Failure to do so may cause significant performance degradation. Proper leak checks must be performed. Using isolation valves does not
automatically void any LG product warranty, however, a limited warranty may be voided in whole or part should any field supplied accessory
fail in any way that causes product failure.
In-line Refrigeration Components
Components such as oil traps, solenoid valves, filter-dryers, sight glasses, tee fittings, and other after-market accessories are not permit-
ted on the refrigerant piping system between the outdoor unit and the indoor unit. Single Zone Wall Mounted Extended Piping systems are
provided with redundant systems that ensure oil is properly returned to the compressor. Sight-glasses and solenoid valves may cause vapor
to form in the liquid stream. Over time, dryers may deteriorate and introduce debris into the system. The designer and installer should verify
the refrigerant piping system is free of traps, sagging pipes, sight glasses, filter dryers, etc.
No Pipe Size Substitutions
Using a different size is prohibited and may result in a system malfunction or failure to work at all.
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