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Step 9 — Make Outdoor-Air Inlet Adjustments
ECONOMIZER AND FIXED OUTDOOR AIR
DAMPER — Hoods are used on all units with economizer or
adjustable self-closing fixed outdoor air damper.
NOTE: If accessory power exhaust or barometric relief pack-
ages are being added to the unit, install power exhaust or baro-
metric relief before installing economizer hoods.
Economizer Hood Assembly
— The economizer hood is
shipped in a package secured to the outside of the unit. The
hood assemblies must be field-assembled. The 48AW,AY units
are side supply and side return. The return duct limits access to
economizer filters from below.
The 48AJ,AK,AW,AY020-050 units have two hoods on ev-
ery unit. The 48AJ,AK,AW,AY051 and 060 units have 3 hoods
on every unit.
NOTE: Before assembly of the economizer hood, check along
the outer edges of the economizer assembly for any seal strip
protruding past the flanges. Trim the excess seal strip so that it
is flush with the economizer assembly flanges.
Perform the following procedure to assemble the economizer
hood.
1. Apply black seal strip (provided) to outside top-edge of
hood sides. Wrap seal strip over edge to cover top flange
(6 hood sides). Make sure seal strip covers screw holes.
Allow strip to overhang
1
/
8
-in. past the end opposite the
mounting flange. See Fig. 23.
2. Assemble hood sides, top, and cross member with
gasketed screws provided. See Fig. 24.
3. Attach 15 green speed clips (provided) to hood top.
4. Apply black seal strip (provided) to mounting flanges of
hood sides being sure to cover mounting holes. See
Fig. 25.
5. Apply black seal strip (provided) to back of hood top
mounting flange. Seal strip of hood top mounting flange
must press tightly against seal strip of hood side mount-
ing flanges. See Fig. 26.
6. Add gray foam strip (provided) to cross members on bot-
tom tray. See Fig. 27.
7. Attach gray foam strip (provided) to block-off baffle on
outer face of flange. See Fig. 28.
8. Remove the screws on each end and along top of damper
assembly of unit. Remove top 4 screws on each side of
filter panel under damper assembly. Set hood assembly in
place and attach to unit using these screws.
9. Remove screws along bottom of damper assembly.
Locate and mount block-off baffle using these screws.
10. Assemble 2 filter tracks side-by-side with the assembled
ends together.
11. Attach one mounting angle to the assembled end of the
filter track. See Fig. 29.
12. Attach 9 green speed clips (provided) to hood side panels.
Engagement section of clip faces up and towards the out-
side of the hood side panels.
13. Attach remaining mounting angle to other end of the filter
track with no. 10 screws provided.
14. Place filter track assembly in bottom of hood by attaching
to hood with speed clips and gasketed screws provided.
NOTE: Be sure the filters are installed with the airflow in the
correct direction.
15. Attach black seal strip (provided) to filter cover. Seal strip
should be applied centered over the holes of the one
flange, making sure to fully cover holes and centered over
the other large flange. See Fig. 30.
16. Slide two 20 x 25-in. filters into cross members of hood
assembly. Attach filter cover over filters with screws and
speed clips provided.
HOOD SIDE
TOP
FLANGE
SEAL
STRIP
BLACK
Fig. 23 — Adding Seal Strip to Top of Hood Sides
Fig. 24 — Economizer Hood Assembly
(Right Side/Center Economizer Hood Shown)
HOOD SIDE
MOUNTING
FLANGE
Fig. 25 — Adding Seal Strip to Sides of Hood Top
Mounting Flange
a48-8498