46
Rev. 2
PRODUCT DESIGN
A closed return duct system must be used, with the return
duct connected to the furnace. Supply and return connec-
tions to the furnace may be made with flexible joints to re-
duce noise transmission, if desired. If a central return is
used, a connecting duct must be installed between the unit
and the utility room wall so the blower will not interfere with
combustion air or draft. The room, closet, or alcove must
not be used as a return air chamber.
When the furnace is used in connection with a cooling unit,
the furnace should be installed in parallel with or on the up-
stream side of the cooling unit to avoid condensation in the
heating element. With a parallel flow arrangement, the damp-
ers or other means used to control the flow of air must be
adequate to prevent chilled air from entering the furnace and,
if manually operated, must be equipped with means to pre-
vent operation of either unit unless the damper is in the full
heat or cool position.
When the furnace is heating, the temperature of the return
air entering the furnace must be between 55°F and 100°F.
COUNTERFLOW INSTALLATIONS
A filter rack is shipped with the furnace for counterflow in-
stallation. If this filter rack is used, the side of the plenum
must be at least as tall as dimension "A" shown below.
"A"
Min
Return Air
Optional
Access
Door
Counterflow Filter Rack
Disposable Permanent
Disposable
Permanent
GCI_045_30
15 1/2
8
2 - 16 x 20 x 1
2 - 10 x 20 x 1
GCI_070_30
15 1/2
8
2 - 16 x 20 x 1
2 - 10 x 20 x 1
GCI_070_35/40
19 3/4
8
2 - 20 x 20 x 1
2 - 10 x 20 x 1
GCI_090_30
14 1/4
13
2 - 16 x 20 x 1
2 - 15 x 20 x 1
GCI_090_50
24 1/4
13
2 - 25 x 20 x 1
2 - 15 x 20 x 1
GCI_115_40
17 3/4
11
2 - 20 x 20 x 1
2 - 15 x 20 x 1
GCI_115_50
23 1/2
11
2 - 25 x 20 x 1
2 - 15 x 20 x 1
GCI_140_50
23 1/2
11
2 - 25 x 20 x 1
2 - 15 x 20 x 1
All filter sizes are based on high speed operation.
COUNTERFLOW FILTER SIZE CHART
Minimum Recommended Filter Sizes
Qty. - Nominal Size Inches
Furnace Model
(Square Inch Surface Area)
Dimension
"A"
HORIZONTAL INSTALLATIONS
Filter(s) must be installed external to the furnace casing for
horizontal installations. For most installations it is prefer-
able to use a central return with filters installed in the duct
behind the return air grill. In this way filter replacement is
relatively simple by merely removing the grille, rather than
going into the attic or crawl space.
Refer to the Upflow/Horizontal Filter Size chart on Recom-
mended Minimum Filter Sizes.
NOTE: The HFC Filter cabinets (used with Amana GSI fur-
naces) will not match the bottom opening of a GUIA fur-
nace.
ADDITIONAL FILTERING ACCESSORIES
External Filter Rack Kit (EFR)
The external filter rack kit is intended to provide a location
external to the furnace casing, for installation of a perma-
nent filter on upflow model furnaces. The rack is designed to
mount over the indoor blower compartment area of either
side panel, and provide filter retention as well as a location
for attaching return air ductwork.
Electronic Air Cleaner (EAC) or Media Air Cleaner
(MAC)
The electronic air cleaner and media air cleaner are multi-
positional high efficiency air filtration devices that can be
installed in any position, except with the access door facing
down. The best location for the air cleaner is in the return air
duct next to the blower compartment. Before installing the
air cleaner, consider the application. The electronic air cleaner
must be readily accessible for periodic inspection and clean-
ing of the pre-filters and electronic cells while the media air
cleaner must be readily accessible for periodic inspection
and replacement of the media cartridge (MAF), to maintain
maximum efficiency and trouble-free operation.
Accomodator (ACG1625 or ACG2025) (Filter Cabinet)
The Accomodator ia a filter cabinet that provides a location
external to the furnace casing for installation of a filter on
upflow model furnaces using bottom return. The
Accomodater gives the homeowner the option of using many
choices of filter types and sizes. The filter sizes that may be
used are 1", 2" and 4".
Horizontal Filter Housing (HR20or 25 & HRB20 or25)
The Horizontal Filter Housing provides a location external to
the furnace casing for installation of a filter(s) on upflow model
furnaces using side air return(s). The Horizontal Filter Hous-
ing gives the homeowner the option of using many choices
of filter types and sizes. The filter sizes that may be used
are 1", 2" or 4".
Note: For complete details on each of the additional filtering
accessories, refer to the instructions provided with each ac-
cessory.
