American Standard GRWF130A94A0A Installation Manual page 21

Flue gas vent pipe
restrictor orifi ce
(shown installed)
Figure 13A
Flexible
Figure 13B
Gasket
Figure 14
in place. As an alternative, B-Vent may be used for fresh
air. A 3" OD collar for fresh air is shipped loose with the
boiler for connecting to the 3" metal vent pipe. If B-Vent
is used, replace the installed 3.5" OD collar with the 3" OD
collar provided with the boiler. Exhaust vent and fresh air
intake system components to be supplied by the installer.
General Venting Guidelines
a) Connect the vent system to only one appliance.
b) The minimum clearance between vent pipes and com-
bustible materials must be six inches.
c) Avoid an excessive number of bends.
d) Horizontal runs should pitch upward at least 1/4" per
foot. See Figure 14 and Table 7.
e) Horizontal runs should be as short as possible.
f) Horizontal pipe runs must be supported by hangers,
straps, or other suitable material in intervals at a mini-
mum of every 3 feet.
g) When vent pipe connection must pass through walls or
partitions of combustible material, a thimble must be
used and installed according to local codes.
h) Vent pipe through the roof should be extended to a
height determined by the National Fuel Gas Code or
local codes. It should be capped properly to prevent
rain water from entering the vent. Roof exit should be
waterproofed.
Flue gas vent
pipe adapter
Flue gas vent
pipe restrictor
Figure 13C
orifi ce
i) A boiler shall not be con-
nected to a chimney or
fl ue serving a separate
appliance designed to
burn solid fuel.
j) Apply other good venting
practices as stated in the
venting section of the
National Fuel Gas Code
NFPA54/ANSI Z223.1
"latest edition".
k) Vent connectors
serving appliances
vented by natural
draft or non-positive
pressure shall not be
connected into any
portion of a mechani-
zed draft system ope-
rating under positive
pressure.
NOTE:
The manufacturer of your boiler does not test any
detectors and makes no representations regarding
any brand or type of detector.
THROUGH THE WALL VENT TERMINATIONS (excerp-
ted from NFPA54 - National Fuel Gas Code - See illustra-
tion in Appendix C.
A mechanical draft venting system shall terminate at least
3 ft (0.9 m) above any forced air inlet located within 10 ft
(3.0 m).
Exception No. 1: This provision shall not apply to the
combustion air intake of a direct-vent appliance.
Exception No. 2: This provision shall not apply to the
separation of the integral outdoor air inlet and fl ue gas
discharge of listed outdoor appliances.
A mechanical draft venting system of other than direct-vent
type shall terminate at least 4 ft (1.2 m) below, 4 ft (1.2 m)
horizontally from, or 1 ft (300 mm) above any door, operable
window, or gravity air inlet into any building. The bottom of
the vent terminal shall be located at least 12 in. (300 mm)
above grade.
The vent terminal of a direct-vent appliance with an input
of 10,000 Btu/hr (3 kW) or less shall be located at least 6
in. (150 mm) from any air opening into a building and such
an appliance with an input over 10,000 Btu/br (3 kW) but
not over 50,000 Btu/hr (14.7 kW) shall be installed with a 9
in. (230 mm) vent termination clearance, and an appliance
with an input over 50,000 Btu/hr (14.7 kW) shall be at least
a 12 in. (300 mm) vent termination clearance. The bottom
of the vent terminal and the air intake shall be located at
least 12 in. (300 mm) above grade.
Through-the-wall vents for Category II and Category IV
appliances and noncategorized condensing appliances shall
not terminate over public walkways or over an area where
condensate or vapor could create a nuisance or hazard or
could be detrimental to the operation of regulators, relief
valves, or other equipment. Where local experience indi-
cates that condensate is a problem with Category I and
Category III appliances, this provision shall also apply.
TABLE 7
Gas Vent Termination
Roof Pitch Minimum Height
Flat to 7/12 1.0 Feet*
Over 7/12 to 8/12 1.5 Feet
Over 8/12 to 9/12 2.0 Feet
Over 9/12 to 10/12 2.5 Feet
Over 10/12 to 11/12 3.25 Feet
Over 11/12 to 12/12 4.0 Feet
Over 12/12 to 14/12 5.0 Feet
Over 14/12 to 16/12 6.0 Feet
Over 16/12 to 18/12 7.0 Feet
Over 18/12 to 20/12 7.5 Feet
Over 20/12 to 22/12 8.0 Feet
* This requirement covers most instal-
lations
18-CG02D1-4
21