Page 4
STEP 2 −− REFRIGERANT PIPING −− Flush-
ing 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 Dave-
Net.
CAUTION −
DO NOT attempt to flush and re−use ex-
isting line sets or indoor coil when the system con-
tains
contaminants (i.e., compressor burn out).
NOTE − When installing refrigerant lines longer than 50
feet, refer to the Refrigerant Piping Design and Fabrication
Guidelines manual available on DaveNet (Corp. 9351−L9),
or contact the Technical Support Department Product Ap-
plication 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
Field Connec-
tions
Recommended Line Set
Liquid
Line
Suction
Line
Liquid
Line
Suction
Line
L15 Line Set
−018
3/8"
(10
mm)
3/4" (19
mm)
3/8"
(10
mm)
3/4" (19
mm)
L15−41 15 ft. −
50 ft. (4.6 m − 15
m)
−024
−030
−036
−042
3/8"
(10
mm)
7/8" (22
mm)
3/8"
(10
mm)
7/8" (22
mm)
L15−65 15 ft. −
50 ft. (4.6 m − 15
m)
−048
−060
3/8"
(10
mm)
1−1/8"
(29
mm)
3/8"
(10
mm)
1−1/8"
(29
mm)
Field Fabricated
NOTE Some applications may required 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
protector that will unload scrolls when suction pres-
sure 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 COM-
PRESSOR.
