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7.11.4. Parameter Adjustments
Default indoor air quality economizer operation is based on common or average applications. Adjustments may be made to
the indoor air quality parameters to alter operation or meet required specifications. Use the user interface to change
Parameter 117 through 119. Go to SETTINGS > RTU OPTIONS > EDIT PARAMETER
Select a demand control ventilation mode with Parameter 134. Modes 3 and 4 will bring on the unit blower when demand
control ventilation calls for maximum damper open, and returns to auto-blower when demand control ventilation damper
returns to 0. The other modes only operate when the unit blower is on, but will not bring it on themselves.
Some applications require a different carbon dioxide set point range than default settings. Damper “start open" (Parameter
118 and “full open" (Parameter 119) carbon dioxide set points may be adjusted from 0 to 2000 ppm. Use the following
formula to determine damper travel.
NOTE - When changing carbon dioxide set point range, “start open" set point should be less than “full‐open" set point.
% Damper Travel = carbon dioxide ppm - Start Open ppm X Max Open (Parameter 117) Full Open - Start Open
Full Open - Start Open
Example: An application requires the dampers open at 800 CO
2
ppm and reach full open at 1200. If the carbon
dioxide level in the space reads 1000 ppm, calculate the damper percent open as follows.
% Damper Travel = 1000 - 800 or 200 or .5 = 0.5 x 100 = 50%
1200 - 800 400
Table 32. Demand Control Ventilation Parameters
Control Parameter Control Value
Units Description
No Screen Name
Parameter Short
Description
Min. Default Max.
117 DCV MAX DAMPER OPEN
Demand Control
Ventilation Maximum
Damper Open
0 100 100 %
Maximum allowed demand con
trol ventilation damper open posi
tion.
118 DCV DAMP START OPEN
Demand Control
Ventilation Damper
Start Open
0 700 2000 PPM
Damper “start open" CO
2
set point for Demand Control
Ventilation.
Level where fresh air
damper begins to open.
119 DCV DAMP FULL OPEN
Demand Control
Ventilation Maximum
Damper Full Open
Set Point
0 1200 2000 PPM
Damper “full open" CO
2
set
point for Demand Control
Ventilation.
Level where fresh air
damper is opened to maxim
um.
120 DCV HI TMP OV FL CL
Demand Control
Ventilation Outdoor
Air Control Hi
Temperature Override
Full Closed
-31.0 105.0 132.0 °F
High outdoor air temp. where
fresh air damper is closed to
minimum position.
121 DCV HI TMP OV ST CL
Demand Control
Ventilation Outdoor
Air Control Hi
Temperature Override
Start Closing
-31.0 75.0 132.0 °F
High outdoor air temperature
where fresh air damper begins to
close.
122 DCV LO TMP OV FL CL
Demand Control
Ventilation Outdoor
Air Control Low
Temperature Override
Full Closed
-31.0 10.0 132.0 °F
Low outdoor air temperature
where fresh air damper is closed
to minimum position
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