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SIDE RETURN AIR APPLICATIONS
The CB30U unit is shipped from the factory ready for
bottom return air application. You can order an optional
side return air filter kit as listed in table 2.
Table 2. Optional Side Return Air Filter Kit
Model
−21 and −26
All other models
Use the following procedures to configure the unit for side
return air operations:
Step 1.
Remove the coil access panel.
Step 2.
Remove the coil assembly from the cabinet.
Step 3.
Cut the side or sides of the cabinet used for
return air according to the dimensions given in
figure 1 and table 1. For −41, 46, −51 and −65
units, it is recommended that return air come into
the unit from both sides. Therefore, both sides of
the cabinet should be cut for these units.
Step 4.
Set the unit so that it is level. Seal the bottom
opening of the cabinet.
Step 5.
Connect the return and supply air plenums as
required.
SIDE VIEW
B
(EITHER SIDE)
CUT BOTH SIDES OF CABINET FOR −41/46, −51 AND −65 UNITS.
Figure 1. CB30U Side Return Air Dimensions
Table 3. Side Return Air Dimensions
CB30U
-21/26
Model #
inch (mm)
inch (mm)
A
14-1/4 (362)
18-1/4 (464)
B
1-1/8 (29)
1-1/8 (29)
505340M 07/07
Kit Number
65K23
65K24
18-1/4
(464)
A
SIDE
RETURN
AIR
2-3/4
(70)
CB30U
CB30U
CB30U-51
CB30U-65
-31
-41/46
inch (mm)
inch (mm)
18-1/4
18-1/4 (464)
(464)
2-1/8 (54)
3-1/8 (79)
Brazing Connections
All CB30U coils are equipped with a factory−installed,
internally mounted expansion valve. Use Lennox L15
(sweat) series line sets as shown in table 2 or use
field−fabricated refrigerant lines. L10 (flare) line sets may
be used by cutting off flare nut. Refer to the piping section
of the Lennox Unit Information Service Manual for proper
size, type, and application of field−fabricated lines.
Danger of explosion!
Can cause equipment damage, injury,
or death.
When using a high pressure gas such
as dry nitrogen to pressurize a
refrigeration
system, use a regulator that can control
the pressure down to 1 or 2 psig (6.9 to
13.8 kPa).
SUCTION LINE
LIQUID LINE
Figure 2. Brazing Connections
To prevent the build up of high levels of nitrogen
when purging, be sure it is done in a well ventilated
area. Purge low pressure nitrogen (1 to 2 psig)
through the refrigerant piping during brazing. This
will help to prevent oxidation and the introduction of
moisture into a system.
Table 4. Refrigerant Line Sets
CB30MV
LIQUID
UNIT
LINE
3/8 in
−21/26
(10 mm)
3/8 in
−31 −41/16
(10 mm)
3/8 in
−51
(10 mm)
3/8 in
−65
(10 mm)
Page 4
WARNING
or
air
AIR HANDLER UNIT
IMPORTANT
VAPOR/
L10
SUCTION
LINE SETS
LINE
L10−26
5/8 in.
20 ft. − 50 ft.
(16 mm)
(6 m − 15 m)
L10−41
3/4 in.
20 ft. − 50 ft.
(19 mm)
(6 m − 15 m)
L10−65
7/8 in.
30 ft. − 50 ft.
(22 mm)
(9 m − 15 m)
1−1/8 in.
FIELD
(29 mm)
FABRICATED
conditioning
L15
LINE SETS
L15−26
20 ft. − 50 ft.
(6 m − 15 m)
L15−41
20 ft. − 50 ft.
(6 m − 15 m)
L15−65
30 ft. − 50 ft.
(9 m − 15 m)
FIELD
FABRICATED
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