Whirlpool W10100870 User Manual

Page of 28
8
Unconfined Space
A water heater in an unconfined space uses indoor air for 
combustion and requires at least 50 cubic feet for each 
1,000 BTUH of the total input for all gas appliances. The 
table below shows a few examples of the minimum square 
footage (area) required for various BTUH inputs.
30,000
45,000
60,000
75,000
90,000
105,000
120,000
135,000
188
281
375
469
563
657
750
844
9 x 21
14 x 20
15 x 25
15 x 31
20 x 28
20 x 33
25 x 30
28 x 30
Typical Room
with 8' Ceiling
Minimum Square
Feet with
8' Ceiling
BTUH
Input
Table 2
IMPORTANT:
• 
The area must be open and be able to provide the 
proper air requirements to the water heater. Areas that 
are being used for storage or contain large objects may 
not be suitable for water heater installation. 
• 
Water heaters installed in open spaces in buildings with 
unusually tight construction may still require outdoor 
air to function properly. In this situation, outside air 
openings should be sized the same as for a confined 
space. 
• 
Modern home construction usually requires supplying 
outside air into the water heater area. 
Confined Space 
For the correct and proper operation of this water heater, 
ample air must be supplied for the combustion, ventilation, 
and dilution of flue gases. Small enclosures and confined 
areas must have two permanent openings so that sufficient 
fresh air can be drawn from outside of the enclosure. One 
opening shall be within 12 inches of the top and one within 
12 inches of the bottom of the enclosure as shown in 
Figure 4.
The size of each opening (free area) is determined by the 
total BTUH input of all gas utilization equipment (i.e., water 
heaters, furnaces, clothes dryers, etc.) and the method by 
which the air is provided. The BTUH input can be found on 
the water heater data plate. Additional air can be provided 
by two methods:
1.  All air from inside the building.
2.  All air from outdoors.
Figure 4
Opening Locations-
Confined Spaces
12” maximum
Permanent
openings to 
the outside or 
additional
rooms within 
the building
Closet
 or
other
confined
space
12” maximum
All Air from Inside the Building
When additional air is to be provided to the confined area 
from additional room(s) within the building, the total volume 
of the room(s) must be of sufficient size to properly provide 
the necessary amount of fresh air to the water heater 
and other gas utilization equipment in the area. If you are 
unsure that the structure meets this requirement, contact 
your local gas utility company or other qualified agency for 
a safety inspection. 
Each of the two openings shall have a minimum free area 
of 1 square inch per 1,000 BTUH of the total input rating of 
all gas utilization equipment in the confined area, but not 
less than 100 square inches (Figure 5).
Confined
Space
Figure 5
All Air from Inside Building
Confined Space Installation
Permanent
Openings
1 square
inch/1000
BTUH
(minimum
100 sq. In.)