Refrigerant Piping - Lennox HP21 Series Installation Instructions Manual

Refrigerant Piping

Field refrigerant piping consists of liquid and vapor lines
from the outdoor unit (sweat connections) to the indoor
evaporator coil (typically flare connections). Use Lennox
L15 line sets as shown in table 1 or use field−fabricated re-
frigerant lines. Refer to Refrigerant Piping Guide (Corp.
9351−L9) for proper size, type, and application of field−fab-
ricated lines. Valve sizes are also listed in table 1.
Table 1
Refrigerant Line Sets
Valve Field Size
Connections
Model M d l
Liquid Vapor
Line Line
3/8 in. 3/8 in.
−36
(10 mm) (10 mm)
3/8 in. 7/8 in.
−48
(10 mm) (22 mm)
3/8 in. 7/8 in.
−60
(10 mm) (22 mm)
NOTE − Units are designed for line sets of up to 50 feet (15
m). For applications longer than 50 feet, consult the Len-
nox Refrigerant Piping Guide (Corp. 9351−L9). Select line
Recommended Line Set
L15
Liquid Vapor
Line Sets
Line Line
3/8 in. 3/4 in. L15−41
(10 mm) (19 mm) 15 ft − 50 ft
(4.6 m − 15 m)
L15−65
3/8 in. 7/8 in.
15 ft− 50 ft
(10 mm) (22 mm)
(4.6 m − 15 m)
3/8 in. 1−1/8 in.
(10 mm) (29 mm) Field
Fabricated
set diameters from table 1 to ensure that oil returns to the
compressor.
Installing Refrigerant Line
During the installation of any heat pump or a/c system, it is
important to properly isolate the refrigerant lines to prevent
unnecessary vibration. Line set contact with the structure
(wall, ceiling or floor) causes some objectionable noise
when vibration is translated into sound. As a result, more
energy or vibration can be expected. Closer attention to
line set isolation must be observed.
Following are some points to consider when placing and
installing a high−efficiency outdoor unit:
1- Placement − Be aware some localities are adopting
sound ordinances based on how noisy the unit is from
the adjacent property not at the original installation.
Install the unit as far as possible from the property line.
When possible, do not install the unit directly outside a
window. Glass has a very high level of sound transmis-
sion.
2- Line Set Isolation − The following illustrations demon-
strate procedures which ensure proper refrigerant line
set isolation. Figure 8 shows how to install line sets on
vertical runs. Figure 9 shows how to install line sets on
horizontal runs. Figure 10 shows how to make a transi-
tion from horizontal to vertical. Finally, figure 11 shows
how to place the outdoor unit and line set.
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