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OPTIONAL DURABLADE ECONOMIZER — The optional
economizer hood assembly is packaged and shipped in the fil-
ter section. Damper blades and control boards are installed at
the factory and the economizer is shipped in the vertical dis-
charge position.
NOTE: Horizontal discharge block-off plate is shipped with
the air hood package. If unit is to be used for vertical discharge
application, discard this plate.
Assembly
1. Determine if ventilation air is required in building. If so,
determine the minimum amount to be supplied by each
unit and record quantity of ventilation air needed for use
in Step 7.
2. Remove filter access panel by raising panel and swinging
panel outward. Panel is now disengaged from track and
can be removed. No tools are required to remove filter ac-
cess panel. Remove outdoor-air opening panel. Save pan-
els and screws. See Fig. 10. Remove optional outdoor-air
hood package from filter section.
3. Assemble outdoor-air hood top and side plates as shown
in Fig. 11. Install seal strips on hoop top and sides. Put
aside screen retainer and screws for later assembly. Do
not attach hood to unit at this time.
4. Slide economizer into unit and secure with screws. See
Fig. 14.
NOTE: Be sure to engage rear economizer flange under tabs in
vertical return-air opening.
5. To convert to horizontal discharge application:
a.
Rotate the economizer 90 degrees until the econo-
mizer motor faces the condenser section (see Fig. 12).
b.
Rotate the barometric relief damper hinge 90
degrees. Barometric relief damper should open
vertically to operate 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. 13.
6. Insert economizer plug into economizer harness. Remove
tape from barometric relief damper. See Fig. 14. Remove
shipping screw (see Fig. 12).
7. If ventilation air is not required, proceed to Step 8. If ven-
tilation air is required, determine the minimum position
setting for required airflow. See Fig. 15. 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. 15. Tighten screws.
8. Remove tape from outdoor-air thermostat (OAT). Fasten
OAT to inside of hood using screws and speed clips pro-
vided. See Fig. 16. Make sure OAT terminals are posi-
tioned up.
9. Replace outdoor-air opening panel using screws from
Step 2. Replace filter access panel. Ensure the filter ac-
cess panel slides along the tracks and is securely engaged.
10. Fasten hood top and side plate assembly (Fig. 11) to
outdoor-air opening panel with screws provided.
11. Place knob supplied with economizer on OAT. See
Fig. 16. 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 installation
and adjustment. See Fig. 16.
12. Connect OAT per Fig. 17.
13. Slide outdoor-air inlet screen into screen track on hood
side plate. While holding screen in place, fasten screen re-
tainer to hood using screws provided.
NOTE: Refer to Fig. 18 for economizer barometric relief
damper characteristics.
ECONOMIZER
CONTROL
BOARD
BAROMETRIC
RELIEF
DAMPER
ECONOMIZER
PLUG
ECONOMIZER
MOTOR
SHIPPING
SCREW
Fig. 10 — Typical Access Panel Locations
Fig. 11 — Outdoor-Air Hood Details
Fig. 12 — Horizontal Durablade
Economizer Installation
Summary of Contents for 50HJQ004-007
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