24
or suspended furnaces closer than 12--in. (305 mm) to joists. The
sheet metal MUST extend underneath the furnace casing by 1--in.
(25 mm) with the door removed.
The bottom closure panel on furnaces of widths 17--1/2--in. (445
mm) and larger may be used for flame roll--out protection when
bottom of furnace is used for return air connection. See Fig. 25 for
proper orientation of roll--out shield.
ANY COMBINATION OF 1, 2, OR 3 PERMITTED.
A11036
Fig. 22 -- Upflow Return Air Configurations and Restrictions
A11037
Fig. 23 -- Downflow Return Air Configurations
and Restrictions
HORIZONTAL TOP
RETURN NOT
PERMITTED FOR
ANY MODEL
A11038
Fig. 24 -- Horizontal Return Air Configurations and
Restrictions