Duct System And Filters - Lennox CB26UH series Installation Instructions Manual

ABOVE
ALWAYS RUN AN OVERFLOW DRAIN LINE. IF NOT POSSIBLE TO
FINISHED
ROUTE OVERFLOW DRAIN LINE, INSTALL LOW VOLTAGE
SPACE?
OVERFLOW
COMPRESSOR PER INSTRUCTIONS.
COMPACT OVERFLOW SWITCH WITH 3/4" FEMALE SLIP INLET
NO
AND MALE ADAPTER, TWO PART DESIGN FOR USE WHERE
OBSTRUCTIONS PREVENT DIRECT THREADING
OVERFLOW
DRAIN
YES
NOTE WHEN A AIR HANDLER IS LOCATED ABOVE A FINISHED SPACE THE SECONDARY
DRAIN PAN MUST HAVE A LARGER FOOTPRINT THAN THE AIR HANDLER.
SECONDARY
DRAIN PAN
OPTIONAL
SAFETY
PAN
WHEN A COIL IS LOCATED ABOVE A FINISHED SPACE, A 3/4" (19.1MM) SECONDARY DRAIN
LINE MUST BE:
S
CONNECTED TO SECONDARY DRAIN PAN
OR
S
CONNECTED TO THE OVERFLOW DRAIN OUTLET OF THE AIR HANDLER DRAIN PAN.
PRIMARY AND SECONDARY TRAPS MUST BE DEEP ENOUGH TO OFFSET MAXIMUM STATIC
DIFFERENCES GENERALLY, TWO INCHES (51MM).
*LENNOX P−TRAP 49P66 REQUIRES A LARGER INSTALLATION SPACE THAN THE J−TRAP 91P90.
TEST CONDENSATE DRAIN
Test the drain pan and drain line after installation:
1. Pour several quarts of water into drain pan, enough to
fill drain trap and line.
2. Check to make sure the drain pan is draining
completely, no leaks are found in drain line fittings, and
water is draining from the end of the primary drain line.
3. Correct any leaks found.

Duct System and Filters

DUCT SYSTEM
The air handler is provided with flanges for the connection
of the plenum and ducts. The air handler is equipped with
flanges that can form a filter rack for the installation of the
air filter, or the filter may be installed as part of the return air
duct system.
Supply and return duct system must be adequately sized
to meet the system's air requirements and static pressure
capabilities. The duct system should be insulated with a
minimum of 1" thick insulation with a vapor barrier in
conditioned areas or 2" minimum in unconditioned areas.
505059M 0511
OVERFLOW DRAIN LINE
SWITCH KIT. WIRE KIT TO
LENNOX #
X3169
MAIN
AIR HANDLER DRAIN PAN
DRAIN
Figure 11. Typical Main and Overflow Drain
VENT MUST EXTEND
SHUT DOWN
ABOVE HEIGHT OF
COIL DRAIN PAN BY
TWO INCHES (51MM)
CLEAN OUT
PRESS IN
(DO NOT GLUE)
1" X 3/4" X 3/4"
REDUCING
LENNOX* P−TRAP
49P66, J−TRAP #
91P90 OR ANY
PVC SCH 40 P− OR
J−TRAP 3/4"
FOR NEGATIVE PRESSURE COILS (BLOWER
AFTER COIL) TRAPS ARE REQUIRED ON ALL
DRAIN LINES CONNECTED TO COIL.
Table 3. Unit Air Filter Size Chart
Model
−018 / −024
−030 / −036
−037 through −060
Supply plenum should be the same size as the flanged
opening provided around the blower outlet and should
extend at least 3 ft. from the air handler before turning or
branching off plenum into duct runs. The plenum forms an
extension of the blower housing and minimizes air
expansion losses from the blower.
INSTALLING DUCT SYSTEM
Install the conditioned air plenum, ducts and air filters (not
provided) in accordance with NFPA 90B Standard for the
Installation of Warm Air Heating and Air−Conditioning
Systems (latest edition).
Connect supply air duct to the flange on top of the air
handler. If an isolation connector is used, it must be
nonflammable.
Page 8
VENT
TEE WITH
PLUG
2"
(51MM)
TRAP DEPTH
DRAIN LINE SHOULD
SLOPE A MINIMUM OF
ONE INCH PER 10
FEET (25MM PER 3
METERS)
Filter Size
15" x 20" (Effective 22 Mar 11)
18" x 20"
18" x 25"
TO APPROVED
DRAIN