Filter
Top Products
8. Remove tape from outdoor-air thermostat (OAT). Fas-
ten OAT to inside of hood using screws and speed clips
provided. See Fig. 23. Make sure OAT terminals are
positioned up.
9. 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.
10. Fasten hood top and side plate assembly (Fig. 17) to
outdoor-air opening panel with screws provided.
11. Place knob supplied with economizer on OAT. See
Fig. 23. 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. 23.
12. Connect OAT per Fig. 24.
13. 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. 25 for economizer barometric relief damper
characteristics.
H. 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.
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 6.
2. Remove filter access panel by raising panel and swing-
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.
ECONOMIZER
CONTROL
BOARD
BAROMETRIC
RELIEF
DAMPER
ECONOMIZER
PLUG
ECONOMIZER
MOTOR
Fig. 19 — Horizontal Varislide™ Economizer Installation
(90 Degree Rotation)
BLOCK-OFF PLATE
Fig. 20 — Horizontal Discharge Block-Off Plate
WIRING
HARNESS
Fig. 21 — Typical Varislide Economizer and Wiring Harness
EXAMPLE:
Given:
Negative Pressure ...........................0.2in.wg
Outdoor Air .................................900cfm
Determine — Setting—5in.
Fig. 22 — Varislide Economizer Minimum Position Setting
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