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TR1
24 Vac
COM
TR
24
Vac
HOT
12
3
4
5
EF
EF1
+
_
P1
T1
P
T
N
EXH
2V 10V
EXH
Set
Set
2V 10V
2V 10V
DCV
DCV
Free
Cool
B
C
A
D
SO+
SR+
SR
SO
AQ1
AQ
DCV
Min
Pos
Open
Max
N1
C06038
Fig. 71 -- EconoMi$er IV Control
Diff erentia l Enthalpy Control
For different ial ent halpy control, the EconoMi$er IV
controller uses two enthalpy sensors (HH57AC078 and
CRENTDIF004A00), one in the outside air and one in the
return air duct. The EconoMi$er IV controller compares
the outdoor air enthalpy to the return air entha lpy to
determine Ec onoMi$er IV use. The controlle r selects the
lower enthalpy ai r (return or outdoor) for cooling. For
exam ple, when the outdoor air has a lower enthalpy than
the return air, the EconoMi$er IV opens to bring in
outdoor air for free cooling.
Replace the standard outside air dry bulb temperature
sensor with the accessory enthalpy sensor in the same
mounting location. (See Fig. 60.) Mount the return air
enthalpy sensor in the return air duct. (See Fig. 69.)
Wiring is provided in the E conoMi$er IV wiring harness.
(See Fig. 62.) The outdoor entha lpy changeover setpoint is
set with the outdoor enthalpy setpoint potentiometer on
the EconoMi$er IV controller. When using this mode of
change over control, turn the enthalpy setpoint
potentiometer fully clockwise to the D setting.
Indoor Air Quality (IAQ) Sensor Input
The IAQ input can be used for demand control ventilation
control based on the level of CO
2
measured in the space
or return air duct.
There is both a factory-installed (FIOP) CO
2
option
(sensor 8001B with no display, which is mounted on the
side of the EconoMi$er) and a field-installed CO
2
option
(sensor 8002 with display, which is mounted on the re turn
air duct). While performing the same function, they differ
in their ability to be configured. The FIOP version is
preset and requires no changes in most applications. I f a
configuration c hange i s required, service kit #UIP2072
(software CD, cables, and instructions) and a laptop PC
are required. The field-installed version with display can
be configured stand-alone . (See section “CO
2
Sensor
Configuration”).
Mount the accessory IAQ sensor according to
manufacturer specifications. The IAQ sensor should be
wired to the AQ and AQ1 terminals of the controller.
Adjust the DCV potent iometers to corre spond to the DCV
voltage output of the indoor air quality sensor at the
user-determined setpoint. (See Fig. 72.)
0
1000
2000
3000
4000
5000
6000
2345678
800 ppm
900 ppm
1000 ppm
1100 ppm
RANGE CONFIGURATION (ppm)
DAMPER VOLTAGEFOR MAX VENTILATION RATE
CO SENSOR MAX RANGE SETTING
2
C06039
Fig. 72 -- CO
2
Sensor Maximum Range Settings
If a separate field-supplied transformer is used to power
the IAQ sensor, the sensor must not be grounded or the
EconoMi$er IV control board will be damaged.
When using demand ventilation, the minimum damper
position represents the minimum ventilation position for
VOC (volatile organic compounds) ventilation
requirements. The maximum demand ventilation position
is used for fully occupied ventilation.
When demand ventilation control is not being used, the
minimum position potentiometer should be used to set the
occupied ventilation position. The maximum demand
ventilation position should be turned fully clockwise.
Exhaust Setpoint Adjustm ent
The exhaust setpoint will determine when the exhaust fan
runs based on damper position (if accessory power
exhaust is installed). The setpoint is modified with the
Exhaust Fan Setpoint (EXH SET ) potentiom eter. (See Fig.
66.) T he setpoint represents the damper position above
which t he exhaust fans will be turned on. When there is a
call for exhaust, the EconoMi$er IV controller provides a
45 ± 15 second delay before exhaust fan activation t o
allow the dampers to open. This delay allows the damper
to reach the a ppropriate position to avoid unnecessary fan
overload.
Minimum Position Control
There is a minimum damper position potentiometer on the
EconoMi$er IV controller. (See Fig. 66.) The minimum
damper position maintains the minimum airflow into the
building during the occupied period.
When using demand ventilation, the minimum damper
position represents the minimum ventilation position for
VOC (volatile organic compound) ventilation
requirements. The maximum demand ventilation position
is used for fully occupied ventilation.
When demand ventilation control is not being used, the
minimum position potentiometer should be used to set the
occupied ventilation position. The maximum demand
ventilation position should be turned fully clockwise.
580J