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35
Install Economizer Hoods (48ZT,ZW Units) —
The economizer uses a total of 4 outdoor intake hoods, 2 on
each side of the unit. See Fig. 37. Two small hoods (one per
side) are factory-installed and are pivoted inside the unit chas-
sis for shipment. Two large hoods are shipped in packages
located inside the unit. The large hoods (1 on each side) require
field assembly and mounting.
INSTALL SMALL HOODS — To install the small econo-
mizer hoods, perform the following procedure:
1. Remove the 10 screws holding each of the small econo-
mizer hood shipping covers in place.
2. Pivot hoods outward. (There are a total of 2 hoods.)
3. Apply seal strip to vertical flange of hood sides.
4. Install 15 screws (4 each side, 7 across top) around the
outside of each hood. Screws are in the fastener package
taped to the basepan inside the fan section.
5. Apply a bead of RTV or similar sealant to corner of econ-
omizer hood at pivot point to prevent water leaks. (See
Fig. 30.)
INSTALL LARGE HOODS — Large hoods are shipped dis-
assembled in the economizer section of the unit behind the
large economizer hood shipping cover. See Fig. 38 for assem-
bly details for large economizer hoods. To install the large
economizer hoods, perform the following procedure:
1. Remove the 17 screws holding each of the large econo-
mizer hood shipping covers in place.
2. Remove the packages containing the disassembled large
economizer hoods (total of 2 packages). Each package
contains the following: left hood side, right hood side,
hood top, hood front, top filter flange, side filter flanges
(4), bottom support, front support, filters (6), filter clips
(9), seal strip, fasteners.
3. Place seal strip on backside of bottom support along en-
tire length of support, covering 6 clearance holes.
4. Attach bottom support piece to unit. Be sure seal strip is
between bottom support and panel on unit.
5. Place seal strip on
3
/
4
-in. flange on both the left and right
hood side.
6. Attach the side filter flanges to the left and right hood
sides, 2 on each hood side.
7. Attach left and right hood sides to unit. Be sure seal strip
is between hood side and unit.
8. Place seal strip on
3
/
4
-in. flange on hood top.
9. Attach top filter flange to hood top.
10. Attach top hood to unit and to hood sides. Be sure seal
strip is between hood top and unit.
11. Attach front support between left and right hood sides.
12. Place seal strip on all filter flanges.
13. Attach filter clips to front and bottom supports.
14. Install filters and filter clips. Filters are held in place with
filter clips.
15. Attach hood front to hood top and sides.
16. Apply RTV or similar sealant to 6 places shown in
Fig. 38.
ACCESS DOOR
PE VFD
EXHAUST
AIR
LARGE ECONOMIZER
HOOD LOCATION
AUXILIARY
CONTROL BOX
POWER EXHAUST
ACCESS DOOR
SMALL ECONOMIZER
HOOD LOCATION
LEGEND
PE VFD — Power Exhaust Variable Frequency Drive
Fig. 37 — Economizer Hood Location — 48ZT,ZW Units