284816-BIM-B-0707
Unitary Products Group
17
Each vent hood is installed by inserting the top flange
of the hood into the slotted opening in the access panel
and securing in place.
The products of combustion are discharged horizon-
tally through these two screened, hooded vent open-
ings on the upper gas heat access panel.
OPTIONAL ECONOMIZER/MOTORIZED DAMPER RAIN
HOOD
The instruction for the optional economizer/motorized
damper rain hood can be found in the 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 sen-
sors are factory mounted as part of the "Factory
installed" economizer option.
OPTIONAL POWER EXHAUST/BAROMETRIC RELIEF
DAMPER RAIN HOOD
The instructions for the power exhaust/barometric relief
damper rain hood can be found in the kit. The exhaust
fan, all supporting brackets, angles, and the wiring are
factory installed as part of the power exhaust option.
OPTIONAL ECONOMIZER AND POWER EXHAUST
DAMPER SET POINT ADJUSTMENTS AND INFORMATION
Remove the economizer access panel from the unit.
Loosen but do not remove the two panel latches.
Locate the economizer control module, where the fol-
lowing adjustments will be made.
Check that the damper blades move smoothly without
binding; carefully turn the Minimum Position Adjusting
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".
MINIMUM POSITION ADJUSTMENT
With thermostat set to indoor fan on position, or termi-
nals "R" to "G" energized, turn the Minimum Position
Adjusting screw (located on the damper control mod-
ule) counterclockwise until the desired minimum
damper position has been attained.
ENTHALPY SET POINT ADJUSTMENT
The enthalpy set point may now be set by selecting the
desired setpoint shown in the Enthalpy Setpoint Adjust-
ment Figure 9. 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
Setpoint Adjustment Figure 9.
•
For a dual enthalpy operation, carefully turn the set
point adjusting screw fully clockwise past the "D"
setting.
POWER EXHAUST DAMPER SETPOINT
With power exhaust option, each building pressuriza-
tion requirement will be different. The point at which the
power exhaust comes on is determined by the econo-
mizer 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.
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 setpoint,
the actuator is allowed to modulate normally in accor-
FIGURE 8 - VENT AND COMBUSTION AIR HOOD
VENT AIR
OUTLET
HOODS
SLOTTED
OPENINGS IN
ACCESS PANEL
COMBUSTION
AIR INTAKE
HOOD
GAS HEAT
ACCESS
PANELS
EXTREME CARE MUST BE EXCERCISED IN
TURNING ALL SETPOINT, MAXIMUM, AND
MINIMUM DAMPER POSITIONING ADJUST-
MENT SCREWS TO PREVENT TWISTING
THEM OFF.