30
Table 9 – Minimum Allowable Input Rating of
Space--Heating Appliance in Thousands of Btuh per Hour
VENT HEIGHT
FT. (M)
INTERNAL AREA OF CHIMNEY
SQ. IN. (SQ. MM)
12
(7741)
19
(12258)
28
18064)
38
(24516)
Local 99% Winter Design Temperature: 17 to 26 degrees F
6
0
55
99
141
8
52
74
111
154
10
NR
90
125
169
15
NR
NR
167
212
20
NR
NR
212
258
30
NR
NR
NR
362
Local 99% Winter Design Temperature: 5 to 16 degrees F*
6
NR
78
121
166
8
NR
94
135
182
10
NR
111
149
198
15
NR
NR
193
247
20
NR
NR
NR
293
30
NR
NR
NR
377
Local 99% Winter Design Temperature: ---10 to 4 degrees F*
6
NR
NR
145
196
8
NR
NR
159
213
10
NR
NR
175
231
15
NR
NR
NR
283
20
NR
NR
NR
333
30
NR
NR
NR
NR
Local 99% Winter Design Temperature: ---11 degrees F or
lower
Not recommended for any vent configuration.
*The 99.6% heating (db) temperatures found in the 1997 or 2001
ASHRAE Fundamentals Handbook, Climatic Design Information chapter,
Table 1A (United States) and 2A (Canada) or the 2005 ASHRAE Funda-
mentals handbook, Climatic Design Information chapter, and the CD---
ROM included with the 2005 ASHRAE Fundamentals Handbook.
Air for combustion must not be contaminated by halogen
compounds which include chlorides, fluorides, bromides, and
iodides. These compounds are found in many common home
products such as detergent, paint, glue, aerosol spray, bleach,
cleaning solvent, salt, and air freshener, and can cause corrosion
of furnaces and vents. Avoid using such products in the
combustion--air supply. Furnace use during construction of the
building could cause the furnace to be exposed to halogen
compounds, causing premature failure of the furnace or venting
system due to corrosion.
Vent dampers on any appliance connected to the common vent
can cause condensation and corrosion in the venting system. Do
not use vent dampers on appliances common vented with this
furnace.
Additional Venting Requirements
A 4--in. (102 mm) round vent elbow is supplied with the furnace.
A 5--in. (127 mm) or 6-- in. (152 mm) vent connector may be
required for some model furnaces. A field--supplied 4--in. (102
mm) to 5--in. (127 mm) or 4--in. (102 mm) to 6--in. (152 mm)
sheet metal increaser fitting is required when 5--in. (127 mm) or
6--in. (152 mm) vent connector is used. See Fig. 36 -- 48, Venting
Orientation for approved vent configurations.
NOTE
: Vent connector length for connector sizing starts at
furnace vent elbow. The 4--in. (102 mm) vent elbow is shipped
for upflow configuration and may be rotated for other positions.
Remove the three screws that secure vent elbow to furnace, rotate
furnace vent elbow to position desired, reinstall screws. The
factory--supplied vent elbow does NOT count as part of the
number of vent connector elbows.
The vent connector can exit the furnace through one of five
locations on the casing.
CUT HAZARD
Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care
and wear appropriate protective clothing, safety glasses and
gloves when handling parts, and servicing furnaces.
CAUTION
!
1. Attach the single wall vent connector to the furnace vent
elbow, and fasten the vent connector to the vent elbow
with at least two field--supplied, corrosion--resistant, sheet
metal screws located 180
_
apart.
NOTE
: An accessory flue extension is available to extend from
the furnace elbow to outside the furnace casing. See Table 17 for
accessory listing. If flue extension is used, fasten the flue
extension to the vent elbow with at least two field--supplied,
corrosion--resistant, sheet metal screws located 180
_
apart. Fasten
the vent connector to the flue extension with at least two
field--supplied, corrosion resistant sheet metal screws located
180
_
apart.
2. Vent the furnace with the appropriate connector as shown
in Fig. 36 -- 48.
3. Determine the correct location of the knockout to be re-
moved.
4. Use a hammer and screwdriver to strike a sharp blow
between the tie points and work the slug back and forth
until the slug breaks free.
An accessory Vent Guard Kit is REQUIRED for downflow
applications for use where the vent exits through the lower
portion of the furnace casing. Refer to the Vent Guard Kit
Instructions for complete details. See Table 17 for accessory
listing.
58C
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