Form: 2435-3
Arctic Installation and Operation Manual
Revision: 10
P/N 105641-01
Date: 12-1-2018
Thermal Solutions, 1175 Manheim Pike, Lancaster, PA 17601
Web:
Phone:
717-239-7642
Fax:
877-501-5212
Email:
15
When directly open to the outside or ducted
to the outside by
vertical
ducts, each opening
or duct shall have a minimum fee open area
of 1 in
2
per 4000 BTU total input rating of the
boiler(s) in the room.
If ducted to the outside through
horizontal
ducts, each opening or duct shall have a
minimum free area of 1 in
2
per 2000 BTU
total input rating of the boiler(s) in the room.
3.3.1.2
One Permanent Opening Method
One opening commencing within 12” of the
top of the room shall be provided. The
opening shall be directly to the outside or
shall be ducted to the outside with a
horizontal or vertical duct.
The opening or duct shall have a minimum
free area of:
1 in
2
/ 3000 BTU /hour of the total input
rating of all appliances (boilers) in the room.
Additional area must be provided for other air
consuming equipment in the room.
3.3.1.3
Mechanical Air Supply Systems
The combustion air supply may be provided
by a mechanical air supply system. If utilized,
the combustion air must be provided from
the outside at a minimum rate of 0.35 ft
3
/min.
for every 1000 Btu/hr. input for all appliances
located in the space.
If exhaust fans are utilized, additional air shall
be provided to replace the exhausted air.
Each boiler and other appliance must be
interlocked to prevent operation when the
mechanical air supply system is not in
operation.
If the combustion air is provided by a
buildings mechanical ventilation system, the
system shall be sized to provide the specified
combustion air in addition to the ventilation
air requirements.
3.3.2
Louvers, Grilles, and Screens
3.3.2.1
Louvers and Grilles:
The required size of openings for
combustion, ventilation, and dilution air shall
be based on the net free area of each opening.
Where the free area through a design of
louver, grille, or screen is new, it shall be used
in calculating the size opening required to
provide the free area specified. Where the
louver and grille design and free area are not
new, it shall be assumed that wood louvers
have a 25 percent free area, and met louvers
and grilles have 75 percent free area. Non-
motorized louvers and grilles shall be fixed in
the open position.
3.3.2.2
Screens
Minimum Screen Mesh Size:
Screens shall not be smaller than 1/4" mesh.
3.3.2.3
Motorized Louvers:
Motorized louvers shall be interlocked with
the appliance so they are proven in the full
open position prior to main burner ignition
and during main burner operation. Means
shall be provided to prevent the main burner
from igniting should the louver fail to open
during burner startup and to shut down the
main burner if the louver closes during burner
operation.
