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F97CMN and G97CMN: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
15
A10493A
Fig. 19 – Duct Flanges
Return Air Connections
The return-air duct must be connected to bottom, sides (left or right), or a
combination of bottom and side(s) of main furnace casing. Bypass
humidifier may be attached into unused return air side of the furnace
casing, see
A11036
Fig. 20 – Upflow Return Air Configurations and Restrictions
A11037
Fig. 21 – Downflow Return Air Configurations
and Restrictions
A11038
Fig. 22 – Horizontal Return Air Configurations
and Restrictions
Bottom Return Air Inlet
These furnaces are shipped with bottom closure panel installed in bottom
return-air opening. Remove this panel when bottom return air is used.
This panel may be used as the bottom closure of an accessory bottom
return air box, or discarded. To remove bottom closure panel, see
A170123
Fig. 23 – Removing Bottom Closure Panel (2 Screws)
WARNING
!
FIRE HAZARD
A failure to follow this warning could cause personal injury, death
and/or property damage.
Never connect return-air ducts to the back of the furnace. Follow
instructions below.
UPFLOW
DOWNFLOW
YES
NO
NO
YES
YES
120
°
MIN
YES
120
°
MIN
90
°
PERFORATED
DISCHARGE DUCT
FLANGE
ANY COMBINATION OF 1, 2, OR 3 PERMITTED.
HORIZONTAL TOP
RETURN NOT
PERMITTED FOR
ANY MODEL
1.
Lay furnace on the back or side
2.
Remove the two (2) screws that secure the bottom
closure panel to the furnace casing and remove the
panel
SCREWS (2)
BOTTOM
CLOSURE
Representative drawing. Models may vary.