Dunkirk XEB-2 Installation Instructions Manual page 5

I Provision forcombustion andventilationairmustbein accordance w ithSection 53, AirforCombustion andVentilation, of theNational f uelGas Code,ANSIZ223.1-1atest revision, orapplicable p rovisions o fthelocalbuilding codes. I
WARNING
Be sure provide enough fresh air for combustion.
Enough air insures proper combustion and
assures that hazard will develop due to the
lack oxygen.
NOTE
If you use a fireplace or a kitchen or bathroom
exhaust fan, you should install an outside air
intake. These devices will rob the boiler and
water heater of combustion air.
You must provide for enough fresh air to assure
proper combustion. The fire in the boiler uses
oxygen. It must have a continuous supply. The air
in a house contains only enough oxygen to supply
the burner for a short time. Outside air must enter
the house to replace that used by the burner. Study
following examples 1 and 2 to determine your fresh
air requirements.
EXAMPLE 1: Boiler Located in Unconfined Space
An unconfined space is defined as a space whose
volume is not less than 50 cubic feet per 1,000
Btu per hour of the total input rating of all appliances
installed in that space.
If your boiler is in an open area (unpartitioned
basement) in a conventional house, the air that
leaks through the cracks around doors and
windows will usually be adequate to provide air
for combustion. The doors should not fit .tightly.
Do not caulk the cracks around the windows.
Equipment located in buildings of unusually tight
construction shall be provided with air for
combustion, ventilation, and dilution of flue gases
using the methods described in example 2B or
shall be specially engineered. The authority having
jurisdiction must approve specially engineered
installations.
EXAMPLE 2: Boiler Located in Confined Space
A. All Air from Inside the Building: The confined
space shall be provided with two permanent
openings communicating directlywith an additional
room(s) of sufficient volume so that the combined
volume of all spaces meets the criteria for an
unconfined space. The total input of all gas
utilization equipment installed in the
combined space shall be considered in making this
determination. Each opening shall have a
minimumfree area of one square inch per 1,000 Btu
per hour of the total input rating of all gas utilization
equipment in the confined space, but not less that
100 square inches. One opening shall be within 12
inches of the top and one within 12 inches of the
bottom of the enclosure. The minimum dimension of
air openings shall not be less than 3 inches.
B. All Air from Outdoors: The confined space
shall communicate with the outdoors in accordance
with methods 1 or 2. The minimum dimension of
air openings shall not be less than 3 in. Where
ducts are used, they shall be of the same cross-
sectional area as the free area of the openings to
which they connect.
1.Two permanent openings, one commencing
within 12 inches of the top, and one commencing
within 12 inches of the bottom, of the enclosure
shall be provided. The openings shall
communicate directly, or by the ducts, with the
outdoors or spaces (crawl or attic) that freely
communicate with the outdoors.
a) Where directly communicating with the
outdoors or where communicating to the
outdoors through vertical ducts, each
opening shall have a minimum free area of
1 sq. in, per 4000 Btu per hour of total input
rating of all equipment in the enclosure.
(See Figure 3A.)
b) Where communicating with the outdoors
throughhorizontal ducts, each opening shall
have a minimum free area of 1 area of sq.
in. per 2000 Btu per hour of total rating of
all equipment in the enclosure. (See Fig.3B.)