New Or Replacement Line Set - Lennox Merit Series 14HPX Installation Instructions Manual

New or Replacement Line Set

This section provides information on new installation or
replacement of existing line set. If a new or replacement
line set is not required, then proceed to Brazing
Connections on Page 9.
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
refrigerant lines will not create unnecessary vibration and
subsequent sounds.
Also, consider the following when placing and installing a
high−efficiency air conditioner:
REFRIGERANT LINE SET
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 (MM)
Field
Connections
Model
Liquid Vapor
Line Line
−018
3/8 in. 3/4 in
−024
(10 mm) (19 mm)
−030
−036
3/8 in. 7/8 in
−042
(10 mm) (22 mm)
−048
3/8 in. 1−1/8 in.
−060
(10 mm) (29 mm)
NOTE Some applications may required a field provided 7/8" to
1−1/8" adapter
NOTE When installing refrigerant lines longer than 50
feet, contact Lennox
Applications for assistance or Lennox piping manual. To
obtain the correct information from Lennox, be sure to
communicate the following points:
S
Model (14HPX) and size of unit (e.g. −060).
S
Line set diameters for the unit being installed as listed
in Table 2 and total length of installation.
S
Number of elbows and if there is a rise or drop of the
piping.
Recommended Line Set
Liquid Vapor L15
Line Line Line Sets
L15−41
3/8 in. 3/4 in
15 ft. − 50 ft.
(10 (19
(4.6 m − 15
mm) mm)
m)
L15−65
3/8 in. 7/8 in
15 ft. − 50 ft.
(10 (22
(4.6 m − 15
mm) mm)
m)
1−1/8
3/8 in.
in. Field
(10
Fabricated
(29
mm)
mm)
Technical Support Product
MATCHING WITH NEW OR EXISTING INDOOR COIL
AND LINE SET
The RFC1−metering line consisted of a small bore copper
line that ran from condenser to evaporator coil. Refrigerant
was metered
temperature/pressure evaporation effects on refrigerant in
the small RFC line. The length and bore of the RFC line
corresponded to the size of cooling unit.
If the 14HPX is being used with either a new or existing
indoor coil which is equipped with a liquid line which served
as a metering device (RFCI), the liquid line must be
replaced prior to the installation of the 14HPX unit.
Typically a liquid line used to meter flow is 1/4" in diameter
and copper.
LINE SET ISOLATION
Brazing alloys and flux contain materials which are
hazardous to your health.
Avoid breathing vapors or fumes from brazing
operations. Perform operations only in well ventilated
areas.
Wear gloves and protective goggles or face shield to
protect against burns.
Wash hands with soap and water after handling brazing
alloys and flux.
IMPORTANT
The Environmental Protection Agency (EPA) prohibits
the intentional venting of HFC refrigerants during
maintenance, service, repair and disposal of appliance.
Approved methods of recovery, recycling or reclaiming
must be followed.
IMPORTANT
If this unit is being matched with an approved line set
or indoor unit coil which 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. Polyol ester (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 the system
performance and capacity.
Failure to properly flush the system per the
instructions below will void the warranty.
Page 7
into the evaporator
CAUTION
by utilizing
14HPX SERIES