CAUTION:
CUT HAZARD
Failure to follow this caution may result in minor
personal injury.
Use care when cutting support rods in filters to protect
against flying pieces and sharp rod ends. Wear safety
glasses, gloves, and appropriate protective clothing.
CAUTION:
UNIT MAY NOT OPERATE
Failure to follow this caution may result in intermittent
unit operation or performance satisfaction.
For airflow requirements above 1800 CFM, see Air
Delivery table in Product Data literature for specific use
of single side inlets. The use of both side inlets, a
combination of 1 side and the bottom, or the bottom only
will ensure adequate return air openings for airflow
requirements above 1800 CFM.
NOTE:
Side return-air openings can ONLY be used in UPFLOW
configurations. Install filter(s) as shown in Fig. 24.
For bottom return-air applications, filter may need to be cut to fit
some furnace widths. Install filter as shown in Fig. 25.
NOTE:
Remove and discard bottom closure panel when bottom
inlet is used.
VI.
BOTTOM CLOSURE PANEL
These furnaces are shipped with bottom closure panel installed in
bottom return-air opening. This panel MUST be in place when side
return air is used.
To remove bottom closure panel, perform the following:
1. Tilt or raise furnace and remove 2 screws holding front
filler panel. (See Fig. 26.)
2. Rotate front filler panel downward to release holding tabs.
3. Remove bottom closure panel.
4. Reinstall front filler panel and screws.
VII.
GAS PIPING
Gas piping must be installed in accordance with national and local
codes. Refer to NFGC in the U.S. Canadian installations must be
made in accordance with NSCNGPIC and all authorities having
jurisdiction. Gas supply line should be a separate line running
directly from meter to furnace, if possible. Refer to Table 3 for
recommended gas pipe sizing. Risers must be used to connect to
furnace and to meter. Support all gas piping with appropriate
TABLE 2—FILTER INFORMATION
AIR FILTER LOCATED IN BLOWER COMPARTMENT
Furnace
Casing
Width (In.)
Filter Size (In.)
Filter Type
Framed
Side Return
Bottom Return
17-1/2
(1) 16 X 25 X 1†
(1) 16 X 25 X 1† Cleanable
21
(1) 16 X 25 X 1*
(1) 20 X 25 X 1† Cleanable
24-1/2
(1 or 2) 16 X 25 X 1* (1) 24 X 25 X 1† Cleanable
* Filters may be field modified by cutting filter material and support rods (3) in
filters. Alternate sizes can be ordered from your distributor or dealer.
† Factory-provided with furnace.
Fig. 24—Filter Installed for Side Inlet
A93045
FILTER
RETAINER
WASHABLE
FILTER
Fig. 25—Bottom Filter Arrangement
A00290
WASHABLE
FILTER
FILTER
SUPPORT
FILTER
RETAINER
17
1
⁄
2
-IN. WIDE
CASINGS ONLY:
INSTALL FIELD-SUPPLIED
FILTER FILLER STRIP
UNDER FILTER.
1
″
24
1
/
2
″
3
″
21-IN. WIDE
CASINGS ONLY:
SUPPORT RODS (3)
EXTEND 1/4" ON EACH
SIDE OF FILTER AND
REST ON CASING FLANGE
Fig. 26—Removing Bottom Closure Panel
A93047
BOTTOM
CLOSURE
PANEL
FRONT FILLER
PANEL
—19—
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Summary of Contents for CONDENSING GAS FURNACE 355MAV
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