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504719M 09/05
Downflow Application
NOTE
−
If downflow application is required, separately or-
der kit number 83M57 and install per kit’s instructions.
Also, use metal or class I supply and return air plenums.
WARNING
If electric heat section with circuit breakers (ECB29)
are applied to downflow CB29M or CB30M unit, cir-
cuit breakers must be rotated 180
_
to the UP posi-
tion. See ECB29 installation instructions for more
details.
Figure 6
Combustible
Floor Additive
Base
Properly−Sized
Floor Opening
BLOWER
COIL UNIT
Combustible Flooring Additive Base
On combustible flooring, use an additive base (figure 6).
Cut an appropriately sized opening for combustible base
(see dimensions in figure 7). Set the additive base into
opening. Connect supply air plenum to the additive base.
Set the unit on the additive base so flanges of the unit drop
into the base opening and seal against the insulation strips.
The unit is now locked in place. Install return air plenum
and secure with sheet metal screws.
TOP VIEW
OPENING
SIDE VIEW
1-5/8 (41)
11-3/8
(289)
2 (51)
22-1/8 (562)
5/8 (16)
13-3/8 (340)
SUPPLY
AIR
OPENING
Figure 7
18−1/4 (464)
CB29M−21/26 & 31
CB30M−21/26
23−1/4 (591)
CB29M−41 to −65
CB30M−31 to 65
Downflow Combustible Base Dimensions
15 (381)
CB29M−21/26 & 31
CB30M−21/26
20 (508)
CB29M−41 to −65
CB30M−31 to 65
1-5/8 (41)
1-5/8 (41)
inches
(mm)
If the homeowner reports water dripping from supply air dif-
fusers, check the shields and tape. Make sure the tape is
completely attached to the edges of the drip shield, and
that the drip shield is wedged firmly in place.
Field Piping Connections
All CB29M/CB30M coils are equipped with a factory−
installed, internally mounted expansion valve. Use Lennox
L15 (sweat) series line sets as shown in Table 1 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.
Table 1
Refrigerant Line Sets
CB29M
CB29M
Unit
Liquid
Line No.
Vapor/
Suction Line
L10
Line Sets
L15
Line Sets
−21/26
3/8 in
(8 mm)
5/8 in
(16 mm)
L10−26
20 ft. − 50 ft.
(6 m − 15 m)
L15−26
20 ft. − 50 ft.
(6 m − 15 m)
−31 −41
3/8 in
(10 mm)
3/4 in.
(19 mm
L10−41
20 ft. − 50 ft.
(6 m − 15 m)
L15−41
20 ft. − 50 ft.
(6 m − 15 m)
−46 −51
3/8 in
(10 mm)
7/8 in.
(22 mm)
L10−65
30 ft. − 50 ft.
(9 m − 15 m)
L15−65
30 ft. − 50 ft.
(9 m − 15 m)
−65
3/8 in
(10 mm)
1−1/8 in.
(29 mm)
FIELD
FABRI-
CATED
FIELD
FABRI-
CATED
NOTE − CB29M/CB30M series evaporators use nitro-
gen or dry air as a holding charge. If there is no pressure
when the rubber plugs are removed, check the coil or line
set for leaks before installing. After installation, pull a
vacuum on the line set and coil before releasing the unit
charge into the system.
1. Use a wet rag to protect TXV bulb (or remove it) when
brazing suction line.
2. Be aware of filter access panel when connecting lines.
Filter must be accessible.
3. Place heat shield (damp rag) against piping plate and
around the suction line connection. Heat shield must
be in place to guard against damage to the paint.
4. With heat shield in place, sweat in suction line elbow,
provided, and line set. After procedure is completed,
remove heat shield.
5. Place heat shield against piping plate and around the
liquid line connection. Sweat in the liquid line elbow
(provided) and the line set.
6. Refer to instructions provided with outdoor unit for leak
testing, evacuating and charging procedures.
