Lennox MCB Series Installation Instruction

11
15. Align the threaded connections with the
ared refrigerant lines. Tighten the are nuts
lightly at rst to obtain a smooth match as
illustrated in “Figure 24. Making Connections
(Male to Female Connection)”.
Table 3. Refrigerant Piping and Indoor Unit
Connection Sizes
Size
(Btuh)
Liquid Line
in.
Suction Line
in.
9K 1/4 3/8
12K 1/4 1/2
18K 1/4 1/2
24K
3/8 5/8
A
B
CANT ON THE OUTSIDE OF
THE FLARE
MALE FLARE
CONNECTION
Figure 24. Making Connections
(Male to Female Connection)
16. Once snug, continue another half-turn on each nut
which should create a leak-free joint. A torque wrench
may be used to tighten are nuts using “Table 4. Flare
Nut Torque Recommendations”.
17. After refrigerant piping has been installed and checked
for leaks, apply insulation over all ared connections.
IMPORTANT
Always use two wrenches when tightening are nuts to
avoid twisting refrigerant piping. DO NOT over-tighten
are nuts.
TORQUE WRENCH
TO INDOOR
UNIT
TO OUTDOOR UNIT
BACKUP
WRENCH
Figure 25. Tighten Flare Nut
Table 4. Flare Nut Torque Recommendations
Outside
Diameter
Recommended
Torque
No torque wrench
available
Finger tighten and
use an appropriately
sized wrench to turn an
additional:
Inches
1/4 15 ft.-lb. (20 N) 1/4 turn
3/8 26 ft.-lb. (35 N) 1/2 turn
1/2 41 ft.-lb. (56 N) 7/8 turn
5/8 48 ft.-lb. (65 N) 1 full turn
IMPORTANT
Do not allow for excess length of line sets to be left rolled
up as part of the required, or in general. This will also
cause additional performance issues.
IMPORTANT
Do not over-tighten a ared joint. Flared connections
should always be accessible and must be insulated to
prevent condensation.
OUTDOOR UNIT
OUTDOOR UNIT
INDOOR UNIT
INDOOR UNIT
Maximum Line Set
Length
Maximum Line Set
Length
Maximum
Elevation -
Outdooor
Unit BELOW
Indoor Unit
Maximum
Elevation -
Outdooor
Unit ABOVE
Indoor Unit
Minimum Line Set
Length - 10 ft. (3m)
Minimum Line Set
Length - 10 ft. (3m)
Outside Unit BELOW Indoor Unit Outside Unit ABOVE Indoor Unit
Figure 26. Indoor and Outdoor Unit Elevation Relationships

Lennox MCB Series Specifications

General

Brand	Lennox
Model	MCB Series
Category	Air Conditioner
Language	English