Lennox Merit ML17XC1 Series Installation Instructions Manual page 3

IMPORTANT
If this unit is being matched with an approved line set
or indoor unit coil that was previously charged with
mineral oil, or if it is being matched with a coil which
was manufactured before January of 1999, the coil
and line set must be flushed prior to installation. Take
care to empty all existing traps. Polyvinyl ether (PVE)
oils are used in Lennox variable-capacity units charged
with HFC-410A refrigerant. Residual mineral oil can
act as an insulator, preventing proper heat transfer. It
can also clog the expansion device and reduce system
performance and capacity. Failure to properly flush the
system per this instruction and the detailed Installation
and Service Procedures manual will void the warranty.
Flush the existing line set per the following instructions.
For more information, refer to the Installation and Ser-
vice Procedures manual available on LennoxPros.com.
CAUTION - DO NOT attempt to flush and re-use existing
line sets or indoor coil when the system contains contam-
inants (i.e., compressor burn out).
If a new line set is being installed, size the piping per table 2.
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
Polyol ester (POE) oils used with HFC-410A refrigerant
absorb moisture very quickly. It is very important that the
refrigerant system be kept closed as much as possible.
DO NOT remove line set caps or service valve stub caps
until you are ready to make connections.
Model Number
ML17XC1-018-230
ML17XC1-024-230
ML17XC1-030-230
ML17XC1-036-230
ML17XC1-041-230
ML17XC1-042-230
ML17XC1-047-230
ML17XC1-048-230
ML17XC1-060-230
NOTE - When installing refrigerant lines longer than 50 feet, refer to the Refrigerant Piping Design and Fabrication Guidelines manual
available on LennoxPros.com (Corp. 9351-L9), or contact the Technical Support Department 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).
REFRIGERANT LINE SET – INCHES (MM)
Valve Size Connections
Liquid Line Suction Line
3/8" (10 mm) 3/4" (19 mm)
3/8" (10 mm) 7/8" (22 mm)
3/8" (10 mm) 1-1/8" (29 mm) *
* Some applications may require a field-provided 1-1/8" to 7/8" adapter.
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.
LIQUID LINE FILTER DRIER INSTALLATION
The provided filter drier must be field installed in the liq-
uid line between the outdoor unit's liquid line service valve
and the indoor coil's metering device (fixed orifice or TXV)
as illustrated in figure 5. This filter drier must be installed
to ensure a clean, moisture-free system. Failure to install
the filter drier will void the warranty. A replacement filter
drier is available from Lennox. See Brazing Connections
page 6 for special procedures on brazing filter drier con-
nections to the liquid line.
Typical Liquid Line Filter Drier Installation
LIQUID LINE
SERVICE VALVE
OUTDOOR
UNIT
TABLE 2
Recommended Line Sets
L15 Line Set
Line Set Length
Model
L15-41-20
L15-41-30
L15-41-40 40 feet (12.2 m)
L15-41-50 50 feet (15.2 m)
L15-65-30
L15-65-40 40 feet (12.2 m)
L15-65-50 50 feet (15.2 m)
Field-fabricated
Page 3
WARNING
BRAZE CONNECTION POINTS
LINE
LIQUID LINE
FILTER DRIER
FIGURE 5
Catalog Number
20 feet (6.1 m)
30 feet (9.1 m)
30 feet (9.1 m)
N/A
LIQUID
LINE
89J56
89J57
89J58
89J59
89J60
89J61
89J62
N/A