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III − REFRIGERANT SYSTEM
A − Plumbing
Field refrigerant piping consists of liquid and suction lines
from the condensing unit (sweat connections) to the indoor
evaporator coil (sweat connections). Use Lennox L15
(sweat) series line sets as shown in table 1.
TABLE 1
Unit
Liquid
Line
Suction
Line
L15 Line Sets
−018
−024
−030
3/8 in.
(10 mm)
3/4 in.
(19 mm)
L15−41
15 ft. − 50 ft.
(4.6 m − 15 m)
−036
−042
−048
3/8 in.
(10 mm)
7/8 in.
(22 mm)
L15−65
15 ft. − 50 ft.
(4.6 m − 15 m)
−060
3/8 in.
(10 mm)
1−1/8 in.
(29 mm)
Field
Fabricated
The liquid line and vapor line service valves (figures 9 and
10) and gauge ports are accessible from the outside of the
unit. Use the service ports for leak testing, evacuating,
charging and checking charge.
Each valve is equipped with a service port which has a facto-
ry−installed Schrader valve. A service port cap protects the
Schrader valve from contamination and serves as the pri-
mary leak seal.
Service valves are not rebuildable. If a valve
has failed, you must replace it.
To Access Schrader Port:
1 − Remove service port cap with an adjustable wrench.
2 − Connect gauge to the service port.
3 − When testing is complete, replace service port cap. Tight-
en finger tight, then an additional 1/6 turn.
To Open Service Valve:
1 − Remove the stem cap with an adjustable wrench.
2 − Using the adjustable wrench to keep the valve station-
ary, use a service wrench with a hex−head extension to
back the stem out counterclockwise as far as it will go.
NOTE − Use a 3/16" hex head extension for 3/8" line
sizes or a 5/16" extension for large line sizes.
3 − Replace the stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.
To Close Service Valve:
1 − Remove the stem cap with an adjustable wrench.
2 − Using the adjustable wrench to keep the valve station-
ary, use a service wrench with a hex−head extension to
turn the stem clockwise to seat the valve. Tighten the
stem firmly.
NOTE − Use a 3/16" hex head extension for 3/8" line
sizes or a 5/16" extension for large line sizes.
3 − Replace the stem cap. Tighten finger tight, then tighten an
additional 1/6 turn.
NOTE − Stem cap must be replaced to help prevent
valve leakage.
Service Valve
(Valve Closed)
Schrader valve open
to line set when valve is
closed (front seated)
service
port
service
port cap
stem cap
insert hex
wrench here
(valve front seated)
to outdoor coil
to indoor coil
Service Valve
(Valve Open)
Schrader
valve
service
port
service port
cap
insert hex
wrench here
to indoor coil
to outdoor coil
stem cap
FIGURE 9
Vapor Line Ball Valve – 5 Ton Units Only
Vapor line service valves function the same way as the other
valves, the difference is in the construction. A ball valve is
illustrated in figure 10.
The ball valve is equipped with a service port with a factory−
installed Schrader valve. A service port cap protects the
Schrader valve from contamination and assures a leak−free
seal.
Ball Valve (Valve Open)
FIGURE 10
Schrader valve
service port
service port
cap
stem cap
stem
Use Adjustable Wrench
To open: rotate Stem Clockwise 90°.
To close: rotate Stem Counter-clockwise 90°.
ball
(shown open)
to outdoor coil
to indoor coil