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Cut an opening appropriately sized for combustible base.
Base dimensions are illustrated in figure 11.
1-5/8
(41)
11-3/8
1-5/8
(289)
(41)
20 (508)
SUPPLY
AIR
OPENING
1-5/8
(41)
TOP VIEW
22-1/8 (562)
13-3/8 (340)
5/8
OPENING
(16)
SIDE VIEW
Figure 11. Combustible Base Dimensions
After opening has been cut, set the additive base into
opening. Connect outlet 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.
Brazing Connections
WARNING
Danger of explosion!
Can cause equipment damage, injury,
or death.
When using a high pressure gas such
as dry nitrogen to pressurize a refrig-
eration or air conditioning system, use
a regulator that can control the pres-
sure down to 1 or 2 psig (6.9 to 13.8
kPa).
IMPORTANT
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.
All CB31MV air handlers are equipped with a
factory−installed, internally mounted check/expansion
valve, which is suitable for use in
Lennox L15 (sweat) series line sets as listed in table 2 on
page 9, or use field−fabricated refrigerant lines. L10 (flare)
505341M 04/08
Inches
(mm)
23−1/4
(591)
FOR DOWN−FLOW
APPLICATIONS
2 (51)
applications. Use
R410−A
Page 8
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.
SUCTION LINE
LIQUID LINE
Figure 12. Brazing Connections
NOTE: CB31MV series evaporators use nitrogen 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.
NOTE: See outdoor unit instructions on how to flow
nitrogen through line sets.
Step 1.
Remove access panel.
Step 2.
Remove the refrigerant line caps from the
refrigerant lines.
Step 3.
Use a wet rag to protect TXV sensing bulb (or
remove
it)
connections.
Step 4.
Place a wet rag against piping plate and around
the suction line connection. The wet rag must be
in place to guard against damage to the paint.
Step 5.
With the wet rag in place, position field provided
elbow fitting to air handler's suction line and line
set. Start nitrogen flow before brazing.
Step 6.
After the procedure is completed then remove
the wet rag.
Step 7.
Place wet rag against piping plate and around
the liquid line connection. Position liquid line
elbow to air handler's suction line and to line set.
Start nitrogen flow and begin brazing both
connections and after procedure is completed
then remove both wet rags.
Step 8.
Refer to instructions provided with outdoor unit
for leak testing, evacuating and charging
procedures.
Step 9.
Install access panel.
AIR HANDLER UNIT
when
brazing
suction
line
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