Fresh Air For Combustion - Dunkirk Empire II Installation & Operation Manual

FRESH AIR FOR COMBUSTION
WARNING
Be sure to provide enough fresh air for combustion. Enough air ensures proper combustion and
assures that no hazard will develop due to the lack of oxygen.
I NOTE
If you use a fireplace or a kitchen or a 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 enough fresh air to assure proper combustion. The fire in the boiler uses
oxygen. It must have a continuous supply. The air in the house contains only enough oxygen to
supply the burner for a short time. Outside air must enter the house to replace the air used by
the burner. Study the following examples 1 and 2 to determine your fresh air requirements.
I
EXAMPLE 1: Boiler Located in Unconfined Space
If your boiler is in an open area (unpartitioned basement) in a conventional house, the air that leaks
through the cracks around the 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.
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.
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 directly with 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
combustion equipment installed in the combined space shall be considered in making this
determination. Each opening shall have a minimum free area of one square inch per 1,000 Btu
per hour of the total input rating of all combustion equipment in the confined space, but not less
than 100 square inches. One opening shall be within 12 inches of the top and one within 12
inches of the bottom of the enclosure.
Example: Your boiler is rated at 100,000 Btu per hour. The water heater is rated at 30,000 Btu per
hour. The total is 130,000 Btu per hour. You need two grilles, each with 130 square inches of
FREE opening. Metal grilles have about 60% FREE opening. To find the Iouvered area needed,
multiply the free opening required by 1.7 (130 x 1.7 = 221.0 sq. in. Iouvered area). In this
example, two grilles each having an 8"x 30" (240 sq. in.) Iouvered area would be used.
AIR OPENINGS FOR BOILER LOCATED IN CONFINED SPACE {CLOSET OR UTILITY ROOMi