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505361M 09/07
PLACING OUTDOOR UNIT ON SLAB
Slab may be level or have a slope tolerance away from the
building of not more than two degrees, or two inches per
five feet (51 mm per 1524 mm).
When installing a unit at grade level, the top of the slab
should be high enough above the grade so that water from
higher ground would not collect around the unit as
illustrated in figure 9.
GROUND LEVEL
MOUNTING
SLAB
BUILDING
STRUCTURE
DISCHARGE AIR
Figure 9. Ground Level Slab Mounting
INSTALLING OUTDOOR UNIT ON ROOF
Install the unit a minimum of six inches (152 mm) above the
roof surface to avoid ice build−up around the unit. Locate
the unit above a load bearing wall or area of the roof that
can adequately support the unit. Consult local codes for
rooftop applications.
If unit coil cannot be mounted away from prevailing winter
winds, a wind barrier should be constructed as illustrated in
figure 10. Size barrier at least the same height and width as
outdoor unit. Mount barrier 24 inches (610 mm) from the
sides of the unit in the direction of prevailing winds.
wind barrier
inlet air
Prevailing Winter Winds
inlet air
inlet air
inlet air
Figure 10. Rooftop Application and Wind Barrier
New or Replacement Refrigerant Line Set
This section provides information on new installation or
replacement of existing line set. If a new or replacement
line set is not required, then proceed to
Brazing
Connections
on page 9.
If refrigerant lines are routed through a wall, seal and
isolate the opening so vibration is not transmitted to the
building. Pay close attention to line set isolation during
installation of any HVAC system. When properly isolated
from building structures (walls, ceilings. floors), the
refrigerant lines will not create unnecessary vibration and
subsequent sounds.
REFRIGERANT LINE SET
Field refrigerant piping consists of liquid and vapor lines
from the outdoor unit (braze connections) to the indoor unit
coil (flare or braze connections). Use Lennox L15 (braze,
non−flare) series line set, or use field−fabricated refrigerant
lines as listed in table 2.
Table 2. Refrigerant Line Set
Model
Field
Connections
Recommended Line Set
Liquid
Line
Vapor
Line
Liquid
Line
Vapor
Line
L15
Line Sets
−018
−024
−030
3/8 in.
(10 mm)
3/4 in
(19 mm)
3/8 in.
(10
mm)
3/4 in
(19 mm)
L15−41
15 ft. − 50 ft.
(4.6 m − 15 m)
−036
−042
−048
3/8 in.
(10 mm)
7/8 in
(22 mm)
3/8 in.
(10
mm)
7/8 in
(22 mm)
L15−65
15 ft. − 50 ft.
(4.6 m − 15 m)
−060
3/8 in.
(10 mm)
1−1/8 in.
(29 mm)
3/8 in.
(10
mm)
1−1/8 in.
(29 mm)
Field
Fabricated
NOTE − When installing refrigerant lines longer than 50
feet, contact Lennox Technical Support Product
Applications for assistance or Lennox piping manual. To
obtain the correct information from Lennox, be sure to
communicate the following points:
Model (13HPD) and size of unit (e.g. −060).
Line set diameters for the unit being installed as listed
in table 2 and total length of installation.
Number of elbows and if there is a rise or drop of the
piping.
MATCHING WITH NEW OR EXISTING INDOOR COIL
AND LINE SET
The RFC1−metering line consisted of a small bore copper
line that ran from condenser to evaporator coil. Refrigerant
was metered into the evaporator by utilizing
temperature/pressure evaporation effects on refrigerant in
the small RFC line. The length and bore of the RFC line
corresponded to the size of cooling unit.
If the 13HPD is being used with either a new or existing
indoor coil which is equipped with a liquid line which served
as a metering device (RFCI), the liquid line must be
replaced prior to the installation of the 13HPD unit.
Typically a liquid line used to meter flow is 1/4" in diameter
and copper.
