507206-01
Page 8 of 59
Issue 1337
Air from Outside
If air from outside is brought in for combustion and
ventilation, the confined space shall be provided with two
permanent openings. One opening shall be within 12” (305
mm) of the top of the enclosure and one within 12” (305
mm) of the bottom. These openings must communicate
directly or by ducts with the outdoors or spaces (crawl or
attic) that freely communicate with the outdoors or indirectly
through vertical ducts. Each opening shall have a minimum
free area of 1 square inch per 4,000 Btu (645 mm² per .59
kW) per hour of the total input rating of all equipment in the
enclosure (See Figures 5 and 6).
It is also permissible to bring air for combustion from a
ventilated attic (Figure 8) or ventilated crawl space (Figure
9).
When communicating with the outdoors through horizontal
ducts, each opening shall have a minimum free area of 1
square inch (645 mm²) per 2,000 Btu (.56 kW) per hour of
the total input rating of all equipment in the enclosure. See
Figure 7.
When ducts are used, they shall be of the same cross-
sectional area as the free area of the openings to which they
connect. The minimum dimension of rectangular air ducts
shall be no less than 3 inches (75 mm). In calculating free
area, the blocking effect of louvers, grilles, or screens must
be considered. If the design and free area of protective
covering is not known for calculating the size opening
required, it may be assumed that wood louvers will have 20
to 25 percent free area and metal louvers and grilles will
have 60 to 75 percent free area. Louvers and grilles must be
fixed in the open position or interlocked with the equipment
so that they are opened automatically during equipment
operation.
Figure 5
Equipment in Confined Space - All Air from Outside
(Inlet Air from Crawl Space and Outlet Air to Ventilated Attic)
Figure 6
Equipment in Confined Space - All Air from Outside
(All Air Through Ventilated Attic)
Equipment in Confined Space - all Air from Outside
Figure 7
Figure 8
Equipment in Confined Space
(Inlet Air from Ventilated Attic & Outlet Air to Outside)
Summary of Contents for 95G2DFE
Page 3: ...507206 01 Page 3 of 59 Issue 1337 Figure 1 ...
Page 17: ...507206 01 Page 17 of 59 Issue 1337 A95DF2E 95G2DFE Table 7A ...
Page 18: ...507206 01 Page 18 of 59 Issue 1337 A95DF2E 95G2DFE Table 7B ...
Page 19: ...507206 01 Page 19 of 59 Issue 1337 A95DF2E 95G2DFE Table 7C ...
Page 27: ...507206 01 Page 27 of 59 Issue 1337 Figure 32 ...
Page 34: ...507206 01 Page 34 of 59 Issue 1337 Figure 48 TRAP DRAIN ASSEMBLY USING 1 2 PVC or 3 4 PVC ...
Page 36: ...507206 01 Page 36 of 59 Issue 1337 Figure 50 Table 10 ...
Page 40: ...507206 01 Page 40 of 59 Issue 1337 TYPICAL WIRING DIAGRAM Figure 54 ...
Page 56: ...507206 01 Page 56 of 59 Issue 1337 Start UP Performance Check List ...