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REFRIGERANT PIPING
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 Service
Procedures manual available on LennoxPros.com. CAU-
TION - DO NOT attempt to flush and re-use existing line
sets or indoor coil when the system contains contaminants
(i.e., compressor burn out).
Polyvinyl ether (PVE) oil is used in the EL18XCV com-
pressors. For installations of the EL18XCV unit with re-
frigerant lines or coils previously charged with R410A and
POE oil, Lennox recommends flushing the existing lines
and coil with R410A refrigerant to remove excess POE oil
that may be in the system.
If a new line set is being installed, size the piping per table 1.
TABLE 1
REFRIGERANT LINE SET – INCHES (MM)
Valve Field
Connections
Model
Liquid
Vapor
Line
Line
3/8 in.
3/4 in.
-024
(10 mm)
(19 mm)
-036
3/8 in.
7/8 in.
(10 mm)
(22 mm)
-048
3/8 in.
1-1/8 in.
-060
(10 mm)
(28 mm)
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).
Recommended Line Set
Liquid
Vapor
L15 Line Sets
Line
Line
L15-41
3/8 in.
3/4 in.
15 ft. - 50 ft.
(10 mm)
(19 mm)
(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.
Field Fabricated
(10 mm)
(28 mm)
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).
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.
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.
Polyvinyl ether (PVE) 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.
Some 5-ton units use scroll compressors equipped with
an internal vacuum protector that will unload scrolls
when suction pressure goes below 20 psig. A hissing
sound will be heard when the compressor is running
unloaded. Protector will reset when low pressure in
system is raised above 40 psig. DO NOT REPLACE
COMPRESSOR.
The EL18XCV is a variable-capacity cooling system uti-
lizing variable speed compressor technology. With the
variable speed compressor and variable pumping capac-
ity, additional consideration must be given to refrigerant
piping sizing and application. The guidelines below are to
be used exclusively for the EL18XCV systems.
COOLING SYSTEM (HFC410A)
• Total equivalent length equals 180 feet (piping and all
fittings included).
NOTE – Length is general guide. Lengths may be more or
less, depending on remaining system design factors.
• Maximum linear (actual) length = 150 feet.
• Maximum linear liquid lift = 60 feet.
Page 4
WARNING
WARNING
WARNING
WARNING
IMPORTANT
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