INSTALLATION INSTRUCTIONS
Gas Furnace: N9MSE
440 01 4103 03
21
Specifications subject to change without notice.
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.
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
)
Figure 22
Duct Flanges
A10493
UPFLOW
DOWNFLOW
HORIZONTAL
YES
NO
NO
YES
YES
YES
NO
120
°
MIN
YES
120
°
MIN
YES
120
°
MIN
90
°
90
°
PERFORATED
DISCHARGE DUCT
FLANGE