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A − Plumbing
Field refrigerant piping consists of liquid and vapor lines
from the outdoor unit (sweat connections). Use Lennox
L15 (sweat) series line sets as shown in table 3.
TABLE 3
Refrigerant Line Sets
Field
Connections
Recommended Line Set
Mod-
el
Liquid
Line
Vapor
Line
Liquid
Line
Vapor
Line
L15
Line Sets
−018
−024
−030
−036
3/8 in.
(10 mm)
3/4 in
(19 mm)
3/8 in.
(10 mm)
3/4 in
(19 mm)
L15−41
15 ft. − 50 ft.
(4.6 m − 15 m)
−037
−042
−048
3/8 in.
(10 mm)
7/8 in
(22 mm)
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)
3/8 in.
(10 mm)
1−1/8 in.
(29 mm)
Field
Fabricated
B − Service Valves
IMPORTANT
Only use Allen wrenches of sufficient hardness
(50Rc − Rockwell Harness Scale min). Fully in-
sert the wrench into the valve stem recess.
Service valve stems are factory torqued (from 9
ft lbs for small valves, to 25 ft lbs for large
valves) to prevent refrigerant loss during ship-
ping and handling. Using an Allen wrench rated
at less than 50Rc risks rounding or breaking off
the wrench, or stripping the valve stem recess.
Service valves (figures 13 and 14) and gauge ports are ac-
cessible 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 fac-
tory−installed Schrader valve. A service port cap protects
the Schrader valve from contamination and serves as the
primary leak seal.
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 − 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 − 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.
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 13
Vapor Line Ball Valve – 5 Ton Only
Vapor line service valves function the same way as the oth-
er valves, the difference is in the construction. If a valve has
failed, you must replace it. A ball valve is illustrated in figure
14.
