6139716-UIM-A-0422
6 Johnson Controls Ducted Systems
Note: Applications shown are with XAH indoor coils that do not contain
a horizontal right hand extension pan.
Duct flanges
Duct flanges are integrated into the casing. Fold the flanges into posi-
tion and use screws to anchor the flanges.
Unit connections
There are several ways to handle the supply and return air duct connec-
tions. The location and sizing of the connections depends on the situa-
tion and the method best suited to the installation. Upflow, horizontal or
downflow applications may be used.
Use a transition to match unit opening to correctly size the supply air
duct. See Table 1 for air handler unit inlet and outlet dimensions.
Ductwork that is not designed to match the supply air opening can
cause turbulence inside the plenum. This turbulence can change the
airflow patterns across the electric heater limit switch/switches. If the
factory suggested transition cannot be fabricated, attach a block off
plate (approximately 8 in. high and running the full width of the plenum)
to the supply opening. See Figure 10. The use of this block off plate
enables better air circulation across the limit switches.
Air filters
.
Return air filters are required and must be field supplied. Filtration must
be accomplished external to the unit.
Section V: Electric heater installation
If the air handler requires electric heat, install the electric heat kit
according to the installation instructions included with the kit. After
installing the kit, mark the air handler nameplate to designate the heater
kit that was installed. If no heater is installed, mark the name plate
appropriately to indicate that no heat kit is installed.
Use only 8HK heater kits, as listed on the air handler name plate and in
these instructions. Use data from Table 4 to Table 13 for information on
the required minimum motor speed tap to use for heating operation and
the maximum over-current protection device required as listed for com-
bination of air handler and heater kit.
Figure 7: Suspension support locations for horizontal applications that
require the drain pan extension
Figure 8: Suspension support locations for horizontal applications that
do not require the drain pan extension
Figure 9: Duct attachment
A1769-001
28 3/4 in.
1 1/2 in.
1 in.
Minimum 3/8 in.
threaded rod
Minimum
1 1/2 in. x 1 1/2 in.
(Angle recommended
length 26 in. minimum with
2 in. clearance on both
sides of the air handler)
A1771-001
21 3/4 in.
1 1/2 in.
1 in.
Minimum 3/8 in. threaded rod
Minimum 1 1/2 in. x 1 1/2 in.
(Angle recommended length 26
in. minimum with 2 in. clearance
on both sides of the air handler)
1 in.1 1/2 in.
21 3/4 in.
Minimum 3/8 in. threaded rod
Minimum 1 1/2 in. x 1 1/2 in.
(Angle recommended length 26
in. minimum with 2 in. clearance
on both sides of the air handler)
A1696-001
Duct flanges
Figure 10: Ductwork transition
CAUTION
Use 1/2 in. screws to connect ductwork to the unit. Longer screws
may pierce the drain pan and cause leakage. If drilling pilot holes, drill
only though the field duct and the unit bottom duct flange.
CAUTION
Never operate the equipment without filters.
NOTICE
In some horizontal applications, the service disconnects on the elec-
tric heat kits must be rotated 180° so the up position of the discon-
nect is the ON position. This service disconnect orientation change is
required by UL 60335-2-40 (in reference to all circuit breakers).
A1697-001
Suggested location of block off plateRecommended transition
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