Goodman Amana AMH8 Service Instructions Manual page 36

PRODUCT DESIGN
A return air filter is not supplied with the furnace. The
installer must supply a means of filtering all of the re-
turn air. Filter(s) shall comply with UL900 or CAN/ULC-
S111 Standards. Damage to furnace caused by operating
the unit without filters is not covered by the warranty.
MINIMUM FILTER SIZES for DISPOSABLE FILTERS
FURNACE INPUT
40M / 45M
60M / 70M
80M / 90M
100M / 115M
120M
140M
DISPOSABLE NOMINAL 300 F.M. FACE VELOCIT Y
SIDE RETURN
Cabinet Nominal Approx.
Width Filter Flow Area
(In.) Size (In.) (In.)
All 16x25x1 400
Refer to Minimum Filter Area tables to determine filter area
requirement. NOTE: Filters can also be installed elsewhere
in the duct system such as a central return.
One inch throwaway filters should be sized for a face
velocity of 300 feet per minute or less (14x25x1 throw-
away = 730 CFM maximum, 16x25x1 throwaway = 830
CFM maximum, 18x25x1 throwaway = 940 CFM maxi-
mum, 20x25x1 throwaway = 1040 CFM maximum) All
other filters should be sized according to their
manufacturer's instructions.
To find the minimum filter requirement (in
permanent or disposable filters divide the required air-
flow (CFM) by the rated velocity of the filter, either
300ft/min for disposable filter or 600ft/min for perma-
nent filter. Multiply the number by 144 in.
minimum filter requirement (in
EXAMPLE:
2
Filter Size (in ) =
2
Filter Size (in ) =
Filter Size
Filter Size
36
FILTER SIZE
2
320 in
2
483 in
2
640 in
2
800 in
2
738 in
2
738 in
BOTTOM RETURN
Cabinet Nominal Approx.
Width Filter Flow Area
(In.) Size (In.) (In.)
14" 14X25X1
17-1/2 14X25X1
21 16x25x1
24-1/2 20X25X1
) for either
2
to obtain the
2
).
2
2
1400 CFM x 144 in
600 ft./min. (Permanent)
2
1400 CFM x 144 in
300 (Disposable) ft./min.
2
= 672in Disposable
2
= 336in Permanent
Upflow furnaces with air delivery of less than 1800 CFM:
Use one side return or one bottom return ductwork con-
nection.
Upflow furnaces with air delivery of 1800 CFM or higher:
Use two side returns or one side return and one bottom
return connection.
Guide dimples locate the side and bottom return cutout
locations. Use a straight edge to scribe lines connecting
the dimples. Cut out the opening on these lines. An un-
dersized opening will cause reduced airflow. For bottom
return connection, remove the bottom of the cabinet
before setting the furnace on the raised platform or re-
turn air duct.
A closed return duct system must be used, with the re-
turn duct connected to the furnace. NOTE: Ductwork
must never be attached to the back of the furnace. Sup-
ply and return connections to the furnace may be made
with flexible joints to reduce noise transmission, if de-
sired. If a central return s used, a connecting duct must
be installed between the unit and the utility room wall
350
so the blower will not interfere with combustion air or
350
draft. The room, closet, or alcove
400
must not be used as a return air chamber.
500
When the furnace is used in connection with a cooling
unit, the furnace should be installed in parallel with or
on the upstream side of the cooling unit to avoid con-
densation in the heating element. With a parallel flow
arrangement, the dampers or other means used to con-
trol 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 prevent 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.
UPRIGHT FILTER INSTALLATIONS
Depending on the installation and/or customer prefer-
ence, differing filter arrangements can be applied. Fil-
ters can be installed in the central return register and a
side panel external filter rack kit (upflow filter kit #
EFR01). As an alternative a media air filter or electronic
air cleaner can be used as the requested filter. Refer to
the following minimum filter requirement charts for de-
termination of the minimum filter area to ensure proper
unit performance. The following figures show possible
filter locations. NOTE: A ductwork access door must be
used in counterflow applications to allow filter removal.
If the filter rack is used, the side of the plenum must be
at least as tall as dimension "A" shown in the following
illustration. For dimension of "A" refer to the following
chart.