21
ECONOMI$ER IV CONTROL MODES
Determine the EconoMi$er IV control mode before set up of
the control. Some modes of operation may require different sen-
sors. Refer to Table 7. The EconoMi$er IV is supplied from the
factory with a supply air temperature sensor and an outdoor air
temperature sensor. This allows for operation of the
EconoMi$er IV with outdoor air dry bulb changeover control.
Additional accessories can be added to allow for different types
of changeover control and operation of the EconoMi$er IV and
unit.
Table 7 — EconoMi$er IV Sensor Usage
*CRENTDIF004A00 and CRTEMPSN002A00 accessories are used on
many different base units. As such, these kits may contain parts that
will not be needed for installation.
†33ZCSENCO2 is an accessory CO
2
sensor.
**33ZCASPCO2 is an accessory aspirator box required for duct-
mounted applications.
††CRCBDIOX005A00 is an accessory that contains both 33ZCSENCO2
and 33ZCASPCO2 accessories.
Outdoor Dry Bulb Changeover — The standard controller is
shipped from the factory configured for outdoor dry bulb
changeover control. The outdoor air and supply air temperature
sensors are included as standard. For this control mode, the
outdoor temperature is compared to an adjustable set point
selected on the control. If the outdoor-air temperature is above
the set point, the EconoMi$er IV will adjust the outdoor air
dampers to minimum position. If the outdoor-air temperature is
below the set point, the position of the outdoor air dampers will
be controlled to provide free cooling using outdoor air. When
in this mode, the LED next to the free cooling set point potenti-
ometer will be on. The changeover temperature set point is
controlled by the free cooling set point potentiometer located
on the control. See Fig. 37. The scale on the potentiometer is A,
B, C, and D. See Fig. 38 for the corresponding temperature
changeover values.
Differential Dry Bulb Control — For differential dry bulb
control the standard outdoor dry bulb sensor is used in conjunc-
tion with an additional accessory dry bulb sensor (part number
CRTEMPSN002A00). The accessory sensor must be mounted
in the return airstream. See Fig. 39. Wiring is provided in the
EconoMi$er IV wiring harness. See Fig. 31.
In this mode of operation, the outdoor air temperature is
compared to the return air temperature and the lower tempera-
ture air stream is used for cooling. When using this mode of
changeover control, turn the enthalpy setpoint potentiometer
fully clockwise to the D setting. See Fig. 37.
IMPORTANT: The optional EconoMi$er2 does not
include a controller. The EconoMi$er2 is operated by a 4 to
20 mA signal from an existing field-supplied controller
(such as PremierLink™ control). See Fig. 32 for wiring
information.
APPLICATION
ECONOMI$ER IV WITH OUTDOOR AIR
DRY BULB SENSOR
Accessories Required
Outdoor Air
Dry Bulb
None. The outdoor air dry bulb sensor
is factory installed.
Differential
Dry Bulb
CRTEMPSN002A00*
Single Enthalpy
HH57AC078
Differential
Enthalpy
HH57AC078
and
CRENTDIF004A00*
CO
2
for DCV
Control using a
Wall-Mounted
CO
2
Sensor
33ZCSENCO2
CO
2
for DCV
Control using a
Duct-Mounted
CO
2
Sensor
33ZCSENCO2†
and
33ZCASPCO2**
OR
CRCBDIOX005A00††
0
500
1000
1500
2000
2500
0.05
0.15
0.25
STATIC PRESSURE (in. wg)
FLOW
IN
CUBIC
FEET
PER
MINUTE
(cfm)
Fig. 33 — Barometric Relief Flow Capacity
0
5
10
15
20
25
30
0.13
0.20
0.22
0.25
0.30
0.35
0.40
0.45
0.50
STATIC PRESSURE (in. wg)
FLOW
IN
CUBIC
FEET
PER
MINUTE
(cfm)
Fig. 34 — Outdoor Air Damper Leakage
0
1000
2000
3000
4000
5000
6000
0.05
0.10
0.15
0.20
0.25
0.30
0.35
STATIC PRESSURE (in. wg)
FLOW
IN
CUBIC
FEET
PER
M
INUTE
(cfm)
Fig. 35 — Return Air Pressure Drop
SUPPLY AIR
TEMPERATURE
SENSOR
MOUNTING
LOCATION
SUPPLY AIR
TEMPERATURE
SENSOR
Fig. 36 — Supply Air Sensor Location
