6
all tabs fl at on the inside of the heat duct. After
inserting the damper into the duct, bend over all
tabs fl at on the inside of the heat duct. Seal the
opening between the fi berboard and damper or
fl exible duct.
DUCTING SYSTEM
DUCT REQUIREMENTS
The supply duct system, including the number
and type of registers, will have much more
effect on the performance of the system than
any other factor. The duct must be suffi ciently
large to conduct an adequate amount of air to
each register.
Air ducts should be installed in accordance
with the standards of the National Fire Protec-
tion Association “Standard for Installation of Air
Conditioning and Ventilation Systems” (NFPA
90A), “Standard for Installation of Residence
Type Warm Air Heating and Air Conditioning
Systems” (NFPA 90B), these instructions, and
all applicable codes.
TYPICAL APPLICATIONS
Figure 6. Drain Trap
Elbow
P-Trap
MULTIPLE DUCT APPLICATION
SINGLE DUCT APPLICATION
6
6
4
4
5
2
3
1
5
2
3
6
4
1
7
1
3
2
4
5
6
7
Figure 7. Typical Applications
Note: For highly resistive duct systems it may
be necessary to add an additional return air duct
and or supply to achieve maximum performance
and prevent coil icing and refrigerant fl ood
back.
Ref. No.
Description
12” x 20” Return Air
16” x 20” Air Filter
12” x 20” Grille
Supply Damper
12” or 14” Diameter Flex Return Duct
12” Diameter Flex Supply Duct
12” x 12” x 12” “Y” Fitting
