Page 11
New or Replacement Line Set
This section provides information on new installation or re-
placement of existing line set. If a new or replacement line
set is not required, then proceed to Brazing Connections
on page 13.
Field refrigerant piping consists of liquid and suction 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 – INCHES (MM)
Model
Valve Field
Connections
Recommended Line Set
Liquid
Line
Suction
Line
Liquid
Line
Suction
Line
L15 Line Sets
-036
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)
-042
-048
-060
3/8 in.
(10 mm)
1-1/8 in.
(28 mm)
3/8 in.
(10 mm)
1-1/8 in.
(28 mm) Field Fabricated
NOTE - Some applications may require a field-provided 7/8"
to
1-1/8
"
adapter.
NOTE
-
When installing refrigerant lines longer than 50
feet, refer to the Refrigerant Piping Design and Fabrica
-
tion Guidelines manual available on LennoxPros.com
(Corp. 9351-L9), or contact the Technical Support Depart
-
ment Product Application group for assistance.
NOTE
-
For new or replacement line set installation, refer
to Service and Application Note - Corp. 9112-L4 (C-91-4)
.
WARNING
When using a high pressure gas such as
nitrogen to pressurize a refrigeration or air
conditioning system, use a regulator that can
control the pressure down to 1 or 2 psig (6.9
to 13.8 kPa).
WARNING
Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.
Failure to follow this warning may result in personal
injury or death.
WARNING
Fire, Explosion and Personal Safety hazard.
Failure to follow this warning could result in
damage, personal injury or death.
Never use oxygen to pressurize or purge
refrigeration lines. Oxygen, when exposed
to a spark or open flame, can cause fire and/
or an explosion, that could result in property
damage, personal injury or death.
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 refrig
-
erant lines will not create unnecessary vibration and sub-
sequent sounds.
The compressor is charged with sufficient Polyol ester oil
for line set lengths up to 50 feet. Recommend adding oil to
system based on the amount of refrigerant charge in the
system. No need to add oil in a system with 20 pounds of
refrigerant or less. For systems over 20 pounds - add one
ounce for every five pounds of refrigerant over 20 pounds.
Recommended topping-off POE oils are Mobil EAL ARC
-
TIC 22 CC or ICI EMKARATE RL32CF.
LIQUID LINE FILTER DRIER INSTALLATION
The filter drier (one is shipped with each ML14XC1 unit)
must be field installed in the liquid line between the out
-
door unit's liquid line service valve and the indoor coil's
metering device as illustrated in figure 6. This filter drier
must be installed to ensure a clean, moisture-free sys-
tem. Failure to install the filter drier will void the warranty.
A replacement filter drier is available from Lennox. See
Brazing Connections on page for special procedures on
brazing filter drier connections to the liquid line.
OUTDOOR
UNIT
LIQUID LINE
SERVICE VALVE
LIQUID LINE
FILTER DRIER
LINE
LIQUID
LINE
BRAZE CONNECTION POINTS
FIGURE 6. Typical Liquid Line Filter Drier
Installation
