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Install Ductwork
IMPORTANT:
Install ductwork in accordance with NFPA 90B and any local
codes.
When the furnace is installed so that the supply ducts carry
air circulated by the furnace to areas outside the space
containing the furnace, the return air shall be handled by a
duct or ducts sealed to the furnace casing and terminated
outsides the space containing the furnace.
If there is no complete return air duct system, the return air
connection must be sealed to the furnace casing and run full
size to a location outside the utility room or space housing
the furnace to avoid a negative pressure on the venting
system.
Installation with Return Ducts
A return air duct system is recommended. If the furnace is
installed in a confined space or closet, a return connection must
be run, full size, to a location outside the closet. The air duct in
the closet must be tight to avoid any entrance of air from the
closet into the circulating air.
Installation with an Evaporator Coil
IMPORTANT: When an air conditioning unit is used in
conjunction with the furnace, the evaporator coil must be
installed in the discharge (supply) air. Do not install an evaporator
coil in the return air; excessive condensation will occur within the
furnace.
When installing a WEC coil in a horizontal position with a
horizontal gas furnace, the open end of the A-coil must face the
supply air outlet of the furnace (blow into the open end of the A-
coil). The A-coil should point away from the supply air outlet of
the furnace as shown.
Minimum Filter Requirements Chart
Cooling Airflow Requirement (CFM)—Permanent Minimum Filter Area (sq. in.) Based On 600 ft (182.9 m)
Per Minute Filter Face Velocity
Input Airflow
600
0453BXA
194*
0703BXA
-
0704CXA
-
0904CXA
-
0905DXA
-
1155DXA
-
Cooling Airflow Requirement (CFM)—Disposable Minimum Filter Area (sq. in.) Based On 300 ft (91.4 m) Per
Minute Filter Face Velocity
0453BXA
388*
0703BXA
-
0704CXA
-
0904CXA
-
0905DXA
-
1155DXA
-
*Minimum filter area dictated by heating airflow requirement.
26
800
1,000
194*
240
324*
324*
-
291*
-
432*
-
-
-
-
388*
480
647*
647*
-
583*
-
863*
-
-
-
-
A
Installation without an Evaporator Coil
If a cooling coil is not installed with the furnace, then a removable
access panel should be provided in the supply plenum for
purposes of inspecting the heat exchanger. This opening must be
accessible when the furnace is installed. It must be large enough
that the heat exchanger can be viewed for possible openings
using light assistance or so that a probe can be inserted for
sampling the airstream. The cover for the opening must be leak
tight.
Filter Specifications
Filters are not supplied with these furnaces. It is the furnace
installer's responsibility to install properly sized filters in
accordance with the Minimum Filter Requirements Chart.
Filters must comply with UL900 or CAN/ULCS111 Standards.
If the furnace is installed without filters, the warranty will be
voided.
Areas and dimensions shown for cleanable filters are based
on filters rated at 300 ft (91.4 m) per minute face velocity.
On upflow models, guide dimples show the location of the
side return cutout. Use a straight edge to scribe lines
connecting the guide dimples. Cut out the opening along
these lines
An undersized opening will cause reduced airflow.
1,200
1,400
288
-
324*
336
291*
336
432*
432*
388*
388*
486*
486*
576
-
647*
672
583*
672
863*
863*
777*
777*
971*
971*
A. Supply
B. Return
1,600
2,000
-
-
-
-
384
-
432*
-
388*
480
486*
486*
-
-
-
-
768
-
863*
-
777*
960
971*
971*
B
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