International comfort products N9MSB Installation Instructions Manual page 21

INSTALLATION INSTRUCTIONS
subbase, or a factory−approved air conditioning coil casing. DO
NOT cut main furnace casing to attach supply side air duct,
humidifier, or other accessories. All supply−side accessories
MUST be connected to duct external to furnace casing.
Return Air Connections
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.
Figure 22 Duct Flanges
PERFORATED
DISCHARGE DUCT
FLANGE
440 01 4101 03
The return−air duct must be connected to return−air opening
(bottom inlet) as shown in Figure 27. DO NOT cut into casing
sides (left or right). Bypass humidifier connections should be
made at ductwork or coil casing sides exterior to furnace. (See
Figure 27)
UPFLOW
90°
YES
YES
120°
MIN
NO
Specifications subject to change without notice.
Gas Furnace: N9MSB, N9MSE
DOWNFLOW
YES
YES
120°
MIN
NO
HORIZONTAL
90°
YES
YES
120°
MIN
NO
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