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Vent Air
Outlet Hoods
Combustion Air
Intake Hood
Figure 15: Vent and Combustion Air Hood
Options/Accessories
Electric Heat
Electric heaters are available as a factory-installed option.
These heaters mount in the heat compartment with the
heating elements extending into the supply air chamber. All
electric heaters are fused and intended for use with single
point power supply.
Economizer/Motorized Outdoor Damper Rain Hood
The instruction for the optional economizer/motorized damper
rain hood can be found in the rain hood kit. Use these
instructions when field assembling an economizer rain hood
onto a unit. The outdoor and return air dampers, the damper
actuator, the damper linkage, the outdoor and return air divider
baffles, and all the control sensors are factory mounted as part
of the "Factory installed" economizer option.
Power Exhaust/Barometric Relief Damper and Rain Hood
The instructions for the power exhaust/barometric relief damper
and rain hood can be found in the rain hood kit. The exhaust
fan, all supporting brackets, angles, and the wiring are factory
installed as part of the power exhaust option.
Economizer And Power Exhaust Set Point
Adjustments
Remove the top rear access panel from the unit. Locate the
economizer control module, where the following adjustments
will be made.
Extreme care must be exercised in turning all set point,
maximum and minimum damper positioning adjustment
screws to prevent twisting them off.
24
Minimum Position Adjustment
Slotted Openings in
Access Panel
Enthalpy Set Point Adjustment
Gas Heat
Access Panels
Power Exhaust Damper Set Point (With Or Without Power
Exhaust)
Indoor Air Quality AQ
Indoor Air Quality (indoor sensor input): Terminal AQ accepts a
+2 to +10 Vdc signal with respect to the (AQ1) terminal. When
the signal is below it's set point, the actuator is allowed to
modulate normally in accordance with the enthalpy and mixed
air sensor inputs. When the AQ signal exceeds it's set point
setting and there is no call for free cooling, the actuator is
proportionately modulated from the 2 to 10 Vdc signal, with 2
Vdc corresponding to full closed and 10 Vdc corresponding to
full open. When there is no call for free cooling, the damper
position is limited by the IAQ Max damper position setting.
When the signal exceeds it's set point (Demand Control
Ventilation Set Point) setting and there is a call for free cooling,
the actuator modulates from the minimum position to the full
open position based on the highest call from either the mixed
air sensor input or the AQ voltage input.
Replace the top rear access panel on the unit.
• Check that the damper blades move smoothly without
binding; carefully turn the Minimum Position Adjust screw
(found on the damper control module) fully clockwise and
then set the thermostat indoor fan switch to the ON
position and then OFF or energize and de-energize
terminals "R" to "G".
• With the thermostat set to the indoor fan ON position or
terminals "R" to "G" energized, turn the Minimum Position
Adjusting screw (located on the damper control module)
counterclockwise until the desired minimum damper
position has been attained.
• The enthalpy set point may now be set by selecting the
desired set point shown in the Enthalpy Set Point
Adjustment Figure 16. Adjust as follows:
• For a single enthalpy operation carefully turn the set
point adjusting screw (found on the damper control
module) to the "A", "B", "C" or "D" setting corresponding
to the lettered curve of the Enthalpy Set Point
Adjustment Figure 17.
• For a dual enthalpy operation, carefully turn the set point
adjusting screw fully clockwise past the "D" setting.
• With no power exhaust option, adjust the Exhaust Air
Adjustment Screw fully clockwise. This will allow 2nd
stage cooling to operate.
• With power exhaust option, each building pressurization
requirement will be different. The point at which the power
exhaust comes on is determined by the economizer
damper position (Percent Open). The Exhaust Air
Adjustment Screw should be set at the Percent Open of
the economizer damper at which the power exhaust is
needed. It can be set from 0 to 100% damper open.
• Optional CO
Space Sensor Kit Part # 2AQ04700324
2
• Optional CO
Sensor Kit Part # 2AQ04700424
2
178113-BIM-D-0906
Unitary Products Group
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