Figure 4
CONFINED SPACE / OUTDOOR AIR
FROM ATTIC
Figure 5
CONFINED SPACE / OUTDOOR AIR
FROM ATTIC & CRAWL SPACE
For an attic installation it is important to keep
insulation 12" or more away from any furnace
openings. Some types of insulating materials may
be combustible.
When horizontal ducts are used to supply air from the
outdoors, they must 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 must not
be less than 3 inches. Each opening must have a free
area of not less than one square inch per 2,000 Btu per
hour of total input of all appliances within the "Confined
Space". These openings must be located 12 in. from the
top and bottom of the furnace area. Neither opening can
be blocked at any time (See Figure 6).
Figure 6
CONFINED SPACE / OUTDOOR
AIR THROUGH HORIZONTAL DUCTS
Furnaces installed with combustion air drawn from
a heated space which includes exhaust fans,
fireplaces, or other devices that may produce a
negative pressure should be considered confined
space installations.
20541501
Issue 0240
Page 10 of 26
Summary of Contents for MPGA 050 B3
Page 1: ...APPLICATION GUIDE GAS FURNACE Fit s All 80 English 02 2004...
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Page 7: ...FURNACE WIRING SPECIFICATIONS 20541501 Issue 0240 Page 5 of 26...
Page 19: ...20541501 Issue 0240 Page 17 of 26 THEORY OF OPERATION...
Page 24: ...SEQUENCE OF OPERATION Direct ignition system control 20541501 Issue 0240 Page 22 of 26...
Page 27: ...TROUBLE SHOOTING With LED Indicator Assistance 20541501 Issue 0240 Page 25 of 26...
Page 28: ...WIRING DIAGRAM 20541501 Issue 0240 Page 26 of 26...
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