All Air From Inside Building; All Air From Outdoors - Williams 5508332 Owner's Manual

Combustion & Ventilation Air (cont.)
WARNING,
DANGER OF PROPERTY DAMAGE,
BODILY INJURY OR DEATH
DRAFT HOOD SPILLAGE, WITH UNOBSTRUCTED
VENTS, INDICATES THAT ADDITIONAL AIR MUST
BE BROUGHT iNTO THE STRUCTURE FROM THE
OUTSIDE. KEEP A WINDOW OPEN (MINIMUM 2
INCHES) NEAR THE APPLIANCE UNTIL A PERMA-
NENT AIR DUCT iS INSTALLED.
4. Spillage means air starvation and a fresh air duct
or air intakes must be installed to provide air directly
to the furnace or other gas appliance.
D. If spillage exists or when the furnace is in a building
of tight construction where the windows and doors are
weatherstripped, air for combustion and ventilation
must be obtained from outdoors or space open to the
outdoors.
provided with free air for proper combustion and ventila-
tion of flue gases by one of the following methods.
A. All Air From Inside Building:
If the confined space adjoins an unconfined space as
defined in EXAMPLE 1, provide two permanent openings,
one within 12 inches of the top and one within 12 inches
of the bottom of the room connecting directly to unconfin-
ed space. Each opening must have a free area of at least
100 square inches or 1 square inch per 1000 Btuh com-
bined input of appliances in one room if combined input
exceeds 100,000 Btuh.
WARNING
DANGER OF PROPERTY DAMAGE,
BODILY INJURY OR DEATH
THE ADJOINING UNCONFINED SPACE MUST
HAVE ADEQUATE AIR INFILTRATION AS DEFINED
IN EXAMPLE 1.
Provide an opening(s) having a total free area of 1 sq.
inch per 4000 Btuh of the total of all appliances. The
required area is shown in Fig. 9, page 10 under the
column for (40,000).
FRESH AIR DUCT
HOLES FROM VENTILATED
ATTIC INTO STUD SPACE
SEE FIG 8
AIR GRILLE TO STUD SPACE
12" MAXFROM FLOOR
HOLES FROM VENTILATED
CRAWL SPACE INTO STUD SPACE
SEE FIG 8
HOLE IN BOTTOM OR
BACK OF FURNACE
INTO OPEN STUD SPACE OR CRAWL SPACE
Fig. 5 shows a typical duct going into ventilated crawl
space or attic.
1. Duct must terminate at a point not more than 1 foot
above the floor.
2. Duct size must be at least 1 inch of free area for
each 4000 Btuh of input of all appliances in area.
EXAMPLE 2.
FURNACE LOCATED IN CONFINED SPACE.
If furnace is installed in a confined space, it must be
FOR EXAMPLE: Your furnace is rated at 50,000 Btu per
hour.The water heater is rated at 30,000 Btu per hour.The
total is 80,000 Btu per hour.You need two grilles, each with
100 square inches of free opening. Metal grilles have about
60% free area, so you need two metal grilles each with
160 square inches of Iouvered area.
Refer to Fig. 7, page 10, which shows grille installation.
Using the previous example, the two connecting rooms
plus the closet must equal at least 500 sq. feet to handle
the combined input 50,000 plus 30,000.
4000 Btuh Per
Square lnch
Opening
Round Rectangular
MINIMUM AREA IN SQUARE FEET
Duct
4" DIA.
4" DIA.
4" D[A.
4" DIA,
4" DIA.
4_ '' DIA
Duct
3"x3" SQ.
3"x3" SQ.
3"x4" SQ.
3"x4" SQ.
3"x5" SQ.
3"x5" SQ.
Max. Btuh
Input
30,000
35,000
40,000
45,000
50_00
60_00
*Unconfined Space
Min. Area In Sq. Ft.
8' Ceiling Height
188
219
250
281
312
375
*Can be two or more rooms joined by ventilation grilles.
B. All Air From Outdoors:
If confined space doesn't adjoin an unconfined space
(defined in EXAMPLE 1) then air must be provided from
outdoors or spaces open to outdoors such as attic or crawl
spaces.
Provide two permanent openings, one within 12 inches of
top, one within 12 inches of bottom of room connecting
directly, or by using ducts, with the outdoors or areas open
to outdoors.
If opening connects directly to, or within vertical duets,
the free area of each opening must be at least 1 square
inch per 4000 Btuh combined input of appliances in area.
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