Duct Connections - Trane UHMB060ACV3VA Installer's Manual

7
CONFINED
SPACE
Confined spaces are installations with less than 50 cu.
ft. of space per 1000 BTU/hr input from all equipment
installed. Air for combustion and ventilation require-
ments can be supplied from inside the building as in
Figure 8 or from the outdoors, as in Figure 9.
1. All air from inside the building as in Figure 8: The
confined space shall be provided with two perma-
nent openings communicating directly with an addi-
tional room(s) of sufficient volume so that the com-
bined volume of all spaces meets the criteria for an
unconfined space. The total input of all gas utiliza-
tion equipment installed in the combined space
shall be considered in making this determination.
Refer to Table 3 for minimum open areas require-
ments.
2. All air from outdoors as in Figure 9: The confined
space shall be provided with two permanent open-
ings, one commencing within 12 inches of the top
and one commencing within 12 inches of the bot-
tom of the enclosure. The openings shall communi-
cate directly, or by ducts, with the outdoors or
spaces (crawl or attic) that freely communicate with
the outdoors. Refer to Table 3, for minimum open
areas requirements.
TABLE 3
MINIMUM FREE AREA IN SQUARE INCHES
EACH OPENING (FURNACE ONLY)
Furnace
Air
Maximum
From
BTUH/INPUT
Inside
Rating
60,000 100
80,000 100
100,000 100
120,000 120

DUCT CONNECTIONS

Air duct systems should be installed in accordance with
standards for air conditioning systems, National Fire
Protection Association Pamphlet No. 90. They should
be sized in accordance with ACCA Manual D or which-
ever is applicable.
Central furnaces, when used in connection with cooling
units, shall be installed in parallel or on the upstream
side of the cooling coil to avoid condensation in the heat
exchanger.
18-CD30D1-9
Air From Outside
Vertical Horizontal
Duct Duct
15 30
20 40
25 50
30 60
Installer's Guide
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