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STEP 3 -- REFRIGERANT PIPING —
Flushing Existing Line Set & Indoor Coil
F
lush the existing line set per the following instruc
tions. For more information, refer to the Installation
and Service 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
contaminants (i.e., com
pressor burn out).
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).
TABLE 1
REFRIGERANT LINE SET — INCHES (MM)
Model
Liquid
Line
Vapor
Line
L15
Line Sets
Feet (Meters)
-024 and
-030
3/8” (10)
3/4” (19)
L15 line set sizes are depen
dent on matching system com
ponents. See SL18XP1 Engi
neering Handbook to determine
correct line set sizes.
-036, -042
and -048
3/8” (10)
7/8” (22)
-060
3/8” (10)
1-1/8”
(29)
Field-Fabricated
NOTE — Some applications may require a field-provided 7/8” to
1-1/8” adapter.
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 installa
tion. Take care to empty all existing traps. Polyol es
ter (POE) oils are used in Lennox 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 sys
tem performance and capacity.
Failure to properly flush the system per this instruc
tion and the detailed Installation and Service Proce
dures manual will void the warranty.
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 Haz
ard. Failure to follow this warning could re
sult 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.
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.
IMPORTANT !
Some scroll compressors have an internal vacuum
protection devices that will unload scrolls when
suction pressure goes below 20 psig. A hissing
sound will be heard when the compressor is run
ning unloaded. The protection device will reset
when pressure in system rises above 40 psig. This
is normal operation. DO NOT replace compressor.
