24
441 01 2613 05
Specifications are subject to change without notice
low
!
velocity filters meet the minimum size areas for 300 FPM or
less.
Figure 22
Optional Duct Standoff
!
NAHA001TK
in(mm)
Filter
20 x 25 (508 x 635 mm)
Optional Filter Rack
16
(406)
14.5
(368)
25
1/16
(637)
25
1/16
(637)
6
7/8
(175)
23
1/2
(570)
18
1/2
(470)
22
1/2
(572)
20
(508)
Optional Filter Rack Installation: Side Return
Center the filter rack on the side panel, flush with the bottom edge
of the furnace. Mark the fastening holes. Drill the fastening holes
in the side panel and fasten the filter rack in place with sheet metal
screws. See
Figure 23
and
Figure 24
.
Figure 23
Side Return Filter Rack
Filter
25-23-05-4a
25-23-05-3
Filter
Filter
Using Two
Filter Racks
Figure 24
Filters Installed on Two Sides
Internal Filter in Bottom-Return Installation
When installing a bottom
!
mounted filter inside the furnace, install
the filter clips on the edge of the bottom duct opening with the wider
end of the clips toward the blower, as shown in
Figure 25.
Clips
may be obtained from your distributor or fabricated from sheet
metal (
Figure 26
). Insert filter into side clips first and push filter
back until it is fully engaged into back clip.
Center Clip
side-to-side
Figure 25
Bottom Mounted Filter
25-24-18-1
9
″
Figure 26
Filter Clip Construction
!
in(mm)
26 Ga. Galvanized Steel
FAST part number 1008482
3
″
1
1
/
4
″
1
1
/
2
″
11
/
16
″
(76.2)
(38.1)
(31.8)
(27)
NOTE:
If filters are only suitable for heating application, advise
homeowner that filter size may need to be increased if air
conditioning is added.
Addition Of Air Conditioning
When a refrigeration coil is used in conjunction with this furnace, it
must be installed on the discharge side of the furnace to avoid
condensation in the heat exchanger. All furnaces are designed
with a break
!
away duct flange on the supply air side of the furnace.
This allows for installation in the horizontal right or downflow
applications. The coil installation instructions must be consulted
for proper coil location and installation procedures. With a parallel
flow arrangement, dampers must be installed to prevent chilled air
from entering the furnace. If manually operated dampers are
used, they must be equipped with a means to prevent operation of
either unit unless the damper is in full heat or full cool position.
Copper or plastic tubing may be used for the condensate drain line.
National Excelsior Company
www.excelsiorhvac.com
Subject to change without notice.
