Specifications

B. Range of adjustment is from 0-100% (2-10V); in most applications the minimum position is adjusted to allow
10% to 25% outside air to enter the system.
C. The Outside Air Damper Minimum Position potentiometer can be adjusted at any time.
D. Whenever the "G" (supply fan) signal is present, the damper will open to this minimum position unless:
a. It may modulate to a greater position if overridden by the CO
2
sensor (DCV).
b. It may not open if overridden by the discharge air temperature sensor (Freeze Protect Mode).
3. DCV Max — Demand Control Ventilation (DCV) Maximum Setpoint
A. The DCV maximum position potentiometer allows the installer to limit the amount of outdoor air flow into the
building when the DCV overrides the mixed air sensor.
B. Setting the DCV maximum position of the damper prevents the introduction of large amounts of hot or cold air
into the space.
C. Note: If the DCV maximum position is set below the outside air damper minimum position, the minimum
position overrides the DCV maximum position (negating the function of the DCV).
4. DCV Set — Demand Control Ventilation (DCV) Setpoint
A. The DCV can be any sensor that provides a 2-10Vdc output. The DCV modulates the outdoor damper to
provide ventilation based on occupancy. Typically, a carbon dioxide (CO
2
) sensor is used to indirectly monitor
occupancy level.
B. No cooling signal (e.g.Y1, Y2) is required for the DCV to override the outdoor air damper when ventilation
requires outdoor air.
C. The controller must receive a "G" (supply fan) signal to open the damper.
D. Range of adjustment is from 2 Volts to 10 Volts.
E. The DCV setpoint can be adjusted at any time.
F. The controller compares the CO
2
sensor input to the setpoint setting to determine the damper minimum
position.
a. If the actual CO
2
level is below the setpoint, then the damper minimum position is determined by the
damper minimum position potentiometer setting.
b. If the actual CO
2
level rises above the setpoint, then the damper minimum position is overridden
proportionally more open.
c. If the discharge air temperature drops below 48°F (Freeze Protect Mode), the DCV input will be
overridden and the damper may not open.
G. Compatible CO
2
sensors will have a 2-10Vdc output for a 0-1500 ppm CO
2
input.
H. Ensure proper polarity of the sensor wires when connecting to the economizer controller. Incorrect polarity
negates the sensor signal.
5. Economizer Setpoint
A. Only the coolest, driest outside air is used for economizer operation when the potentiometer is on setting "D".
For greatest energy savings, the potentiometer is on setting "A".
B. Adjustment range is A, B, C, or D
a. Setting "A" = 73F db or 27
Btu/lbm @ 50% RH
b. Setting "B" = 70F db or 25
Btu/lbm @ 50% RH
c. Setting "C" = 67F db or 23
Btu/lbm @ 50% RH
d. Setting "D" = 63F db or 22
Btu/lbm @ 50% RH
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