Filter
Top Products
F. Optional Durablade Economizer
The optional economizer hood assembly is packaged and shipped
in the filter section. Damper blades and control boards are
installed at the factory and the economizer is shipped in the
vertical position.
NOTE: Horizontal discharge block-off plate is shipped with
the air hood package. If unit is to be used for vertical dis-
charge application, discard this plate.
Assembly:
1. Determine if ventilation air is required for building. If
so, determine the minimum amount to be supplied by
each unit and record quantity of ventilation air needed
for use in Step 6.
2. Remove filter access panel by raising panel and s wing-
ing panel outward. Panel is now disengaged from track
and can be removed. No tools are required to remove
filter access panel. Remove outdoor-air opening panel.
Save panels and screws. See Fig. 19. Remove optional
outdoor-air damper hood package from filter section.
3. Assemble outdoor-air hood top and side plates as shown
in Fig. 20. Install seal strips on hood top and sides.
Put aside screen retainer and retainer screw for later
assembly. Do not attach hood to unit at this time.
4. To convert to horizontal discharge application:
a. Rotate the economizer 90 degrees until the econo-
mizer motor faces the condenser section (see Fig. 21).
b. Rotate barometric relief damper hinge 90 degrees. Baro-
metric relief damper should open vertically to oper-
ate properly.
c. Install horizontal discharge block-off plate over the
opening on the access panel. (Block-off plate MUST
be installed before installing hood assembly.) See
Fig. 22.
5. Insert economizer plug into economizer harness. Re-
move tape from barometric relief damper. See Fig. 23.
6. If ventilation air is not required, proceed to Step 7. If
ventilation air is required, determine the minimum po-
sition setting for required airflow. See Fig. 24. Adjust
minimum position setting by adjusting the screws on
the position setting bracket. Slide bracket until the top
screw is in the position determined by Fig. 24. Tighten
screws.
7. Remove tape from outdoor-air thermostat (OAT). Fas-
ten OAT to inside of hood using screws and speed clips
provided (see Fig. 25). Make sure OAT terminals are
positioned up.
8. Replace outdoor-air opening panel using screws from
Step 2. Replace filter access panel. Ensure the filter
access panel slides along the tracks and is securely
engaged.
9. Fasten hood top and side plate assembly (Fig. 20) to
outdoor-air opening panel with screws provided.
10. Place knob, supplied with economizer, on OAT. See
Fig. 25. Set for 3° F below indoor room thermostat set-
ting. If accessory enthalpy control (EC) is used in place
of OAT, see instructions shipped with EC for installa-
tion and adjustment (see Fig. 25).
11. Connect OAT per Fig. 26.
12. Slide outdoor-air inlet screen into screen track on hood
side plate. While holding screen in place, fasten screen
retainer to hood using screws provided.
NOTE: Refer to Fig. 27 for economizer barometric relief damper
characteristics.
G. Optional PARABLADE Economizer
The optional PARABLADE economizer hood assembly is pack-
aged and shipped in the filter section. Damper blades and
control boards are installed at the factory and the econo-
mizer is shipped in the vertical discharge position.
NOTE: Horizontal discharge block-off plate is shipped with
the air hood package. The PARABLADE economizer can only
be used for vertical discharge applications. Discard this plate.
Fig. 19 — Typical Access Panel Locations
Fig. 20 — Outdoor-Air Hood Details
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