Bryant BFIT 1000, Installation, Operation And Maintenance Manual

Page: 28 / 68

28
D. Optional Room Air for Combustion
1. General Guidelines
a. Room air is optional for commercial
applications. Follow the requirements in
this section when air for combustion is
supplied from boiler room.
b. Avoid combustion air contaminants in
the boiler room. Permanently remove any
contaminants found in the boiler room. If
contaminants cannot be removed, do not
use room air for combustion.
2. Outdoor Openings to Boiler Room
a. P rovide combustion and ventilation air
to the boiler room or enclosure.
Follow
the National fuel Gas Code
, ANSI Z223.1,
or, i
n Canada, Installation Code for Gas
Burning Appliances and Equipment
, CGA
Standard B149 Code
as well as all applicable
local codes. Use one of the following two
methods.
b. Two Permanent Openings Method:
Provide two permanent openings, one
within 12 in. (300 mm) of the top of the
enclosure and one within 12 in. (300 mm)
of the bottom of the enclosure. Openings
must communicate directly, or by ducts,
with the outdoors or spaces that freely
communicate with the outdoors. Ensure
the ducts to communicate with outdoors
have the same cross-sectional area as the
free area of the opening to which they are
connected.
i.
Direct communication or through vertical
ducts:
minimum free area of each
opening shall be 1 in.
2
/4000 Btu/hr
(550 mm
2
/kW)
of total input rating
of all appliances within the enclosure.
ii. Horizontal ducts: minimum free area
of each opening shall be
1 in.
2
/2000
Btu/hr (1100 mm
2
/kW)
of total
input rating of all appliances within
the enclosure.
c. One Permanent Opening Method:
Provide
one permanent opening, commencing
within 12 in. (300 mm) of the top of the
enclosure.
E. Removing Existing Boiler
When an existing boiler is removed from a
common venting system, the common venting
system is likely to be too large for proper
venting of the remaining appliances. At the time
of removal of an existing boiler, the following
steps should be performed with each appliance
remaining connected to the common venting
system. Make sure the appliance are not in
operation while carrying out these stapes.
WARNING
Sources of combustion air contaminants,
including chlorines, chlorofluorocarbons
(CFC’s), petroleum distillates, detergents,
volatile vapors or other chemicals must not
be present in the boiler room. If any of these
contaminants is present, severe boiler corrosion
and failure will result.
d. Motorized Louvers or DBFITers:
M otorized
louvers or dBFITers must be
interlocked with the boiler to allow ignition
and firing of the burner only when louvers
are in the fully-open position. Wire the
interlock to the Auto Reset External Limit
connections. See Section VIII “Electrical”.
3. Terminations
a. For standard horizontal sidewall
terminations, see Figure 7 and 8. For
vertical roof terminations, see Figure 9 and
10.
b. When using room air for combustion,
use 90° elbow or tee for sidewall vent
termination.
The opening shall communicate through a
vertical or horizontal duct to the outdoors
or spaces that freely communicate with the
outdoors and shall have a minimum free
area of the following:
i.
1 in.
2
/3000 Btu/hr (700 mm
2
/kW)
of total input rating of all appliances
located within the enclosure.
ii. Not less than the sum of the areas of all
vent connectors in the space.
VII. Venting
(continued)