Bard Bayrd Furnace 403293A - Manual (Page 43)

10) No portion of the venting system can extend
into, or pass through any circulating air duct or
plenum.
11) All vent pipe passing through floors, walls,
and ceilings must be installed with the listed
clearance to combustible materials and be fire
stopped according to local codes. In the
absence of local codes, refer to NFGC
(2223.1)
12) Vent connectors serving Category 1
appliances shall not be connected to any
portion of mechanical draft systems operating
under positive pressure such as Category 111
or IV Venting Systems.
13) A Category I appliance must never be
connected to a chimney that is servicing a
solid fuel appliance. If a fireplace chimney
flue is used to vent this appliance, the
fireplace opening must be permanently
sealed.
14) A vent connector shall be supported without
any dips or sags and shall slope a minimum of
1/4 inch per lineal foot of connector, back
towards the appliance.
15) Vent connectors shall be firmly attached to
drafthood outlets or flue collars by sheet-
metal screws or other approved means,
except vent connectors of listed Type B vent
material which shall be assembled in
accordance
with the manufacturer's
instructions. Joints between sections of
single wall connector piping shall be fastened
by sheet-metal screws or other approved
means,
16) When the vent connector used for Category 1
appliances must be located in or pass through
a crawl space or other area which may be cold,
that portion of the vent connector shall be of
listed double-wall Type B vent material or
material having equivalent insulation qualities.
17) The entire length of sirigie wall metal vent
connector shall be readily accessible for
inspection, cleaning, and replacement.
18) For appliances with more than one input rate,
the minimum vent or connector (Fan Min)
capacity determined from the tables shall be
less than the lowest appliance input rating
and the maximum vent or connector (Fan or
Nat Max.) capacity determined from the tables
shall be greater than the highest appliance
input rating.
13) For single appliance vents:
a) If the vertical vent or tile lined chimney has a
larger diameter or flow area than the vent
connector, use the vertical vent diameter to
determine the minimum vent capacity and the
vent connector diameter to determine the
maximum vent capacity. The flow area of the
vertical vent, however, shall not exceed 7
times the flow area of the listed appliance
categorized vent area, drafthood outlet area
or flue collar area unless designed in
accordance with approved engineering
methods. See Table 9 for calculated areas.
b) For multiple appliance vents:
The flow area of the largest section of vertical
vent or chimney shall not exceed 7 times the
smallest listed appliance categorized vent
area, flue collar area, or draft hood outlet area
unless designed In accordance with approved
engineering
methods. See Table for
calculated areas.
Maximum vent or tile lined chimney flow area = TTfD*)^ x 7
4
* Drafthood outlet diameter, flue collar diameter, or listed
appliar^ce categorized vent diameter.
c) In no case, shall the vent connector be
upsized more than 2 consecutive table size
diameters over the size of the drafthood
outlet, flue collar outlet, or listed apppliance
categorized vent. Example: An appliance
with a 4 inch diameter flue outlet collar or
drafthood outlet cannot be vented with a
connector diameter larger than 6 inches.
20) Masonry chimneys used to vent Category I
central furnaces must be either tile-lined or
lined with a listed metal lining system or
dedicated gas vent. Unlined masonry
chimneys are prohibited. (See Note 1).
21) A fan assisted furnace may be common
vented into an existing masonry chimney
provided:
a. The chimney is currently serving at least
one drafthood equipped appliance.
b. The vent connectors and chimney are
sized in accordance with Tables 7 & 8.
SINGLE APPLIANCE VENTING OF A FAN
ASSISTED FURNACE INTO A TILE LINED,
MASONRY CHIMNEY IS PROHIBITED, THE
CHIMNEY MUST FIRST BE LINED WITH
EITHER TYPE B VENT SIZED IN
ACCORDANCE WITH TABLES 1 OR 2 OR A
LISTED, SINGLE WALL, METAL LINING
SYSTEM, SIZED IN ACCORDANCE WITH
NOTE 22.
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