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Installation shall comply with NFPA-31
Standard for the
Installation of Oil Burning Equipment
(latest edition), and
applicable provisions of local building codes to provide
combustion and ventilation air.
Provide enough fresh air to assure proper combustion. Fire
in the boiler uses oxygen. It must have continuous supply.
Air in the house contains only enough oxygen to supply
burner for short time. Outside air must enter house to
replace air used by the burner. Study following examples 1
and 2 to determine your fresh air requirements.
EXAMPLE 1:
Boiler Located in Unconfined Space
If your boiler is in open area (non partitioned basement) in
conventional house, air that leaks through cracks around
doors and windows will usually be adequate to provide
air
for combustion. D
oors should not fit tightly. Do not caulk
cracks around windows.
Unconfined space is defined as space whose volume is not
less than 50 cubic feet per 1,000 Btu per hour of total input
rating of all appliances installed in that space.
EXAMPLE 2:
Boiler Located in Confined Space
A. All Air from Inside the Building:
Confined space
shall be provided with two permanent openings
communicating directly with additional room(s) of
sufficient volume so that combined volume of all spaces
meets criteria for unconfined space. Total input of all
combustion equipment installed in combined space
shall be considered in making this determination. Each
opening shall have minimum free area of one square
inch per 1,000 Btu per hour of total input rating of all
combustion 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 the
enclosure.
Example: Your boiler is rated at 100,000 Btu per hour.
Water heater is rated at 30,000 Btu per hour. 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 louvered area
needed, multiply free opening required by 1.7 (130 x
1.7 = 221.0 sq. in. louvered area). In this example,
two grilles each having 8” x 30” (240 sq. in.) louvered
area would be used.
FRESH AIR FOR COMBUSTION
WARNING
Asphyxiation, fire hazard. Do not obstruct air
openings to combustion area. Follow instructions
below, to maintain adequate combustion air.
!
NOTICE
Install outside air intake if you use fireplace or
kitchen or bathroom exhaust fan. These devices rob
boiler and water heater of combustion air.
Figure 4 - Air Openings For Boiler Located In
Confined Space (Utility Room
)
PN 240013023, Rev. B [12/31/2020]
