8
111079-01 - 12/20
FR
Installation & Service Manual
WARNING
Adequate combustion and ventilation air must
be provided to assure proper combustion and
to maintain safe ambient air temperatures.
DO NOT install boiler where gasoline or other
flammable vapors or liquids, or sources of
hydrocarbons (i.e. bleaches, fabric softeners,
etc.) are used or stored.
1. Determine volume of space (boiler room).
Rooms communicating directly with the
space in which the appliances are installed,
through openings not furnished with doors, are
considered a part of the space.
Volume(ft
3
) = Length(ft) x Width(ft) x Height(ft)
2. Determine total input of all appliances in the
space.
Add inputs of all appliances in the space and
round the result to the nearest 1000 BTU per
hour.
3. Determine type of space. Divide Volume by
total input of all appliances in space. If the
result is greater than or equal to 50 ft
3
/1000
BTU per hour, then it is considered an
unconfined space
. If the result is less than
50 ft
3
/1000 BTU per hour then the space is
considered a
confined space
.
4. For boiler located in an
unconfined space of a
conventionally constructed building
, the fresh
air infiltration through cracks around windows
and doors normally provides adequate air for
combustion and ventilation.
5. For boiler located in a confined space or an
unconfined space in a building of unusually
tight construction, provide outdoor air.
Outdoor air may be provided with the use of
two permanent openings which communicate
directly or by duct with the outdoors or spaces
(crawl or attic) freely communicating with the
outdoors. Locate one opening within 12 inches
of top of space.
Locate remaining opening within 12 inches of
bottom of space. Minimum dimension of air
opening is 3 inches. Size each opening per
following:
a. Direct communication with outdoors.
Minimum free area of 1 square inch per
4,000 BTU per hour input of all equipment in
space.
b.
Vertical ducts. Minimum free area of 1
square inch per 4,000 BTU per hour input
of all equipment in space. Duct cross-
sectional area shall be same as opening
free area.
c.
Horizontal ducts. Minimum free area of 1
square inch per 2,000 BTU per hour input
of all equipment in space. Duct cross-
sectional area shall be same as opening
free area.
Alternate method for boiler located within
confined space.
Use indoor air if two
permanent openings communicate directly
with additional space(s) of sufficient volume
such that combined volume of all spaces
meet criteria for unconfined space. Size
each opening for minimum free area of 1
square inch per 1,000 BTU per hour input of
all equipment in spaces, but not less than
100 square inches.
6. Louvers and Grilles of Ventilation Ducts
a. All outside openings should be screened
and louvered. Screens used should not be
smaller than 1/4 inch mesh. Louvers will
prevent the entrance of rain and snow.
b. Free area requirements need to consider
the blocking effect of louvers, grilles, or
screens protecting the openings. If the free
area of the louver or grille is not known,
assume wood louvers have 20-25 percent
free area and metal louvers and grilles have
60-75 percent free area.
c. Louvers and grilles must be fixed in the
open position, or interlocked with the
equipment to open automatically during
equipment operation.
2
Pre-Installation
(continued)
!