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18-CD31D1-5
Installer’s Guide
RETURN AIR FILTERS FOR UPFLOW FURNACE
IN HORIZONTAL CONFIGURATION
When the Upflow Furnace is installed in the horizontal con-
figuration, the return air filters must be installed exterior
to the furnace cabinet. Remote filter grilles may be used for
homeowner convenience or the filters may be installed in
the duct work upstream of the furnace. See Figure 21.
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UPFLOW FILTER CLIP / BRACKET INSTALLATION
1. Determine the location to be used. The furnace cabinet
has dimples for location of the alternate furnace clips
(
Side return only
). Pre-drill clearance holes with a
3/16" drill. Bottom return holes are pre-drilled. Attach
clip to bottom channel and rear of unit with screws
provided for bottom return.
2. Install the clips in front and rear of the desired location
using the screws provided. The filter clip with the leaf
spring mounts in the rear of the cabinet. See Figure
22.
UNIT
SIZE
RETURN AIR
BOTTOM
SIDE
17-1/2"
DO NOT CUT DO NOT CUT
21"
DO NOT CUT CUT ON LINE
24-1/2"
DO NOT CUT CUT ON LINE
INSTALLING THE FILTER
The filter may need to be cut to fit the unit depending on
the location of the return air filter.
A score line and the words “CUT HERE” are located on the
end of the filter. If your application requires cutting the
filter, do so as indicted by the score mark.
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TYPICAL DOWNFLOW FURNACE
RETURN AIR FILTER INSTALLATIONS
Two filters are factory supplied for each downflow furnace.
These furnaces require high velocity type air filters. Down-
flow furnace filters must be located outside the furnace
cabinet. Typical installations are shown in Figure 23.
Tables 5 and 6 provide information for installation of the
filter retaining brackets shipped with downflow furnaces.
Conversion kits for horizontal filters are BAYFLTR203
for 17 1/2" width cabinets, BAYFLTR204 for 21" width
cabinets, and BAYFLTR205 for 24" width cabinets. These
include filters and brackets necessary for horizontal filters.
In addition, optional door kit BAYFLTR206 is also avail-
able. See Figures 21 and 23.
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Typical Horizontal Filter Installation
Optional door kit
BAYFLTR206
Optional door kit
BAYFLTR206
SIDE
CUT
-OUT
ALTERNATE SIDE
FILTER CLIPS
LOCATIONS
ALTERNATE BOTTOM
FILTER CLIPS LOCATIONS
