6
Install the base pan around the feeder duct with
the (2) screws through the holes towards the
rear of the base pan.
Slit the corners of the feeder duct down to the
top of the base pan. While the top of the
distribution duct is pulled up with one hand, bend
down each side of the feeder duct tightly to the
base with the other hand. Trim the metal to allow
a one inch flange over the top of the base pan
and seal that flange with the metal tape.
If a “V” or “U”-box crossover system is to be
used, see the instructions provided with the
crossover system.
Figure 4. MA-100 Universal Base,
Bottom Panel
12-1/8
12-1/8
Feeder Duct
Opening
7-1/8 X 2-3/16 Knock-outs
Combustion Air
18-1/4
24-1/2
Figure 5. Feeder Duct Installation
Heat Duct Below Joists
Base
Feeder Duct
Floor
Joists
Cut This Line
Bend Over
Along This Line
1"
Figure 3. Transition and Offset Ducts
Heater Duct Below Joists
Flange
Bend Over Tabs
Base
Floor
Joists
Slit 4 Corners
Bend Down 4 Sides
TRANSITION
DUCT
Floor
Joists
Heater Duct Below Joists
Bend Over Tabs
Flange
Slit 4 Corners
Base
Bend Down 4 Sides
MA-100 Universal Base Installation
The MA-100 base is designed primarily for
replacement installation of the CMF series fur-
nace where the manufactured home duct sys-
tem may be small and restrictive to proper air
flow. The MA-100 base provides approxi-
mately four (4) inches of additional plenum
space before the discharge air enters the manu-
factured home duct system. (See Figures 4
and 5)
Use the bottom panel of the base assembly to
mark the 12-1/8" x 12-1/8" center opening for
the feeder duct. If using the combustion air duct,
select and knock out the combustion air open-
ing to be used. Then mark the 2-1/4" x 7-1/4"
opening for the combustion air duct.
Cut the opening for the feeder duct 14-1/8" x 14-
1/8" in flooring (cutting opening 1" larger all the
way around 12-1/8" x 12-1/8" template mark-
ing). This will allow the four flanges on the
underside of the panel to fit into the opening.
If using the combustion air duct, cut the opening
for the duct about 1/8" larger than the marking
on the floor. Be sure to cut through all insulation
and the bottom board so that the combustion air
duct is unobstructed to the outside air.
Drill a 1" hole for the fuel line through the floor and
bottom board to the outside. Fuel lines are not
supplied with the furnace. They should be
installed to comply with local codes.
Put the bottom base panel in place (See Figure
5). Drop the transition feeder duct upside down
through the opening and mark a 12" x 12"
opening to be cut into the distribution duct.
Remove the bottom panel and transition feeder
duct; then cut the opening into the distribution
duct.
Summary of Contents for CMF 100-PG
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