Operating instructions

FRESH AIR FOR COMBUSTION
Provision for combustion and ventilation air must be in accordance with Section 5.3 of NFGC, Air for Combustion and Ventilation, of the or
applicable provisions of local building codes.
Canadian installations must be installed in accordance with NSCNGPIC and all authorities having jurisdiction.
WARNING: Be sure to provide enough fresh air for combustion. Enough air ensures proper combustion and
ASSURES THAT NO HAZARD WILL DEVELOP DUE TO LACK OF OXYGEN. Failure to follow this warning can cause a fire,
personal injury, or death.
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 house to replace oxygen used by burner. Study
the following examples to determine your fresh air requirements.
CAUTION: Air for combustion must not be contaminated by halogen compounds, which include fluoride, chloride,
bromide, and iodide. These elements are found in aerosol sprays, detergents, bleaches, cleaning solvents, salts, air
fresheners, and other household products. Excessive exposure to contaminated combustion air will result in safety and
performances related problems.
CAUTION: If a fireplace or a kitchen or bathroom exhaust fan is used, an outside air intake should be installed. These
devices rob the boiler and water heater of combustion air which may cause a fire, personal injury or death.
PROCEDURE 1—BOILER LOCATED IN UNCONFINED SPACE
EXAMPLE 1:
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, air that leaks through cracks around doors and windows will
usually be adequate to provide air for combustion. The doors should not fit tightly. Do not caulk cracks around windows.
Equipment located in buildings of unusually tight construction shall be provided with air for combustion, ventilation, and dilution of flue gases
using methods described in example 2B or shall be specially engineered. The authority having jurisdiction must approve specially engineered
installations.
PROCEDURE 2—BOILER LOCATED IN CONFINED SPACE
EXAMPLE 2A: 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 combined volume of all spaces meets criteria for an unconfined space. The total input of all gas utilization equipment installed in 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 gas utilization equipment in confined space, but not less than 100 square inches. One opening shall be within 12
inches of top and one within 12 inches of bottom of enclosure. The minimum dimension of air openings shall not be less than 3 inches.
EXAMPLE 2B: ALL AIR FROM OUTDOORS
The confined space shall communicate with the outdoors in accordance with examples 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 free area of openings to which they connect.
1. Two permanent openings, one commencing within 12 inches of top, and one commencing within 12 inches of bottom of enclosure shall
be provided. The openings shall communicate directly, or by 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 enclosure. (See Table 3A.)
b. Where communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 sq. in. per 2000
Btu per hour of total input rating of all equipment in enclosure. (See Table 3B.)
2. One permanent opening commencing within 12 inches of top of enclosure shall be permitted where equipment has clearance of at least 1
inch from sides and back and 6 inches from front of appliance. The opening shall directly communicate with the outdoors or shall
commmunicate through a vertical or horizontal duct to the outdoors or spaces (crawl or attic) that freely communicate with the outdoors
and shall have a minumm free area of:
a. 1 sq. inch per 3000 Btu per hour of the total input of all equipment located in enclosure (see Table 3C), and
b. Not less than the sum of the areas of all vent connectors in confined space.
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