Specifications

economizer hood assembly.) Once economizer hood as-
sembly is in place, secure it using 10 of the screws from
the fastener package (5 per side).
10. Using 2 of the screws from the fastener package, attach
the top flange of the economizer hood assembly to the
unit top rail. The holes in the top rail are behind the top
rail gasket.
11. Using 4 screws from the fastener package, attach top
and bottom of the channel panels and/or clips to the top
rail and the base rail. Again, the holes in the top rail and
the base rail will be covered by gasketing.
12. Attach filter angle to base rail, using 2 screws from fas-
tener package. Since the holes are covered by the base
rail gasket, locate and punch them out before attaching
the filter angle.
13. Seal any small gaps between flanges and at the top with
RTV to prevent water leakage.
14. Reinstall filters and filter retainers using screws re-
moved earlier.
BAROMETRIC RELIEF/CONSTANT VOLUME POWER
EXHAUST HOOD — The same hood is used for baromet-
ric relief and power exhaust, and is shipped separately from
the base unit, in cartons marked 50DJ900371 for 024 units,
and marked 50DJ900381 for 028 and 030 units.
Barometric relief can only be unit mounted on vertical supply/
return units (50DJ,DK).
Power exhaust (for constant volume units only) can only
be unit mounted on vertical supply/return units (50DJ). Ac-
cessory constant volume power exhaust may be duct mounted
on horizontal supply/return unit 50DW.
IMPORTANT: Modulating power exhaust is for VAV
units only and is unit mounted only on vertical supply/
return unit 50DK. See Modulating Power Exhaust Hood
section on this page. If using power exhaust, the re-
turn duct must have a 90-degree elbow below the unit
to comply with ANSI (American National Standards
Institute) codes.
Cartons contain:
1 — preassembled hood/damper assembly
1 — fastener package (taped to inside of hood)
The fastener package contains:
6 — screws,
1
⁄ 4 AB x
5
⁄ 8 -in. long
2 — seal strips 36-in. long x 1-in. wide x
1
⁄ 8 -in. thick,
with pressure-sensitive adhesive on one side
2 — seal strips, 33-in. long x 1-in. wide x
1
⁄ 8 -in. thick,
with pressure-sensitive adhesive on one side
To install hood:
1. Remove the lagscrews holding hood assembly to ship-
ping skid. See Fig. 15. Before installing the hood on the
unit, remove the channel panel attached to the barometric
relief/power exhaust fan deck and the compressor access
door. Also, remove the middle 2 screws holding the fan
deck to the base rail.
2. Apply the 36-in. long seal strips to the side flanges of the
hood assembly. Apply the 33-in. long seal strips to the
top and bottom flanges of the hood assembly. (On 024
units, which have narrower hoods than 028 and 030 units,
trim the excess seal strip as needed.) Make seal strips flush
with the outer edges of the flanges. Use a punch to punch
out holes for the screws.
Hood assembly is heavy and requires at least 2 people
to handle it.
3. Line up the top flange of the hood assembly with the
6 holes in the fan deck (approximately 6
1
⁄ 2 in. from the
top). Using the 6 screws from the fastener package, se-
cure the top flange of the hood assembly to the fan deck.
Reinstall the 2 screws attaching the fan deck to the base
rail. (The holes in the bottom flange of the hood assem-
bly should line up with these holes.)
4. Reinstall the channel panel between the fan deck and the
compressor access door. The 3 holes in the left side flange
of the hood assembly should line up with the correspond-
ing holes in the fan deck and the channel panel. The 3
holes in the right side flange of the hood assembly should
line up with the holes in the fan deck and the holes in the
channel clip described in Economizer Hoods section on
page 13. Unit is now ready for installation of the econo-
mizer hoods.
MODULATING POWER EXHAUST HOOD — The hood
for modulating power exhaust is shipped separately from the
base unit, in cartons marked 50DJ900571 for 50DK024 units,
and marked 50DJ900581 for 50DK028 and 030 units.
Factory-installed modulating power exhaust can only be
unit mounted on 50DK vertical supply/return VAV unit. If
using modulating power exhaust, the return duct must have
a 90-degree elbow below the unit to comply with ANSI codes.
Accessory, field-installed, modulating power exhaust may be
duct mounted on 50DY units.
Fig. 15 — Power Exhaust/Barometric Relief Hood
14