Bryant DURAPAC 580F User Manual

Page 18

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In this mode of operation, the outdoor air temperature is
compared to the return air temperature and the lower tem-
perature 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. 27.

Outdoor Enthalpy Changeover

For enthalpy control, accessory enthalpy sensor (part num-
ber HH57AC078) is required. Replace the standard outdoor
dry bulb temperature sensor with the accessory enthalpy
sensor in the same mounting location. See Fig. 16. When the
outdoor air enthalpy rises above the outdoor enthalpy
changeover set point, the outdoor-air damper moves to its
minimum position. The outdoor enthalpy changeover set
point is set with the outdoor enthalpy set point potentiome-
ter on the EconoMi$er IV controller. The set points are A, B,
C, and D. See Fig. 30. The factory-installed 620-ohm jumper
must be in place across terminals SR and SR+ on the
EconoMi$er IV controller. See Fig. 16 and 31.

Differential Enthalpy Control

For differential enthalpy control, the EconoMi$er IV con-
troller uses two enthalpy sensors (HH57AC078 and
CRENTDIF004A00), one in the outside air and one in the
return air duct. The EconoMi$er IV controller compares the
outdoor air enthalpy to the return air enthalpy to determine
EconoMi$er IV use. The controller selects the lower enthalpy
air (return or outdoor) for cooling. For example, when the
outdoor air has a lower enthalpy than the return air, the
EconoMi$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 loca-
tion. See Fig. 16. Mount the return air enthalpy sensor in the
return air duct. See Fig. 29. Wiring is provided in the
EconoMi$er IV wiring harness. See Fig. 22. The outdoor
enthalpy changeover set point is set with the outdoor enthalpy
set point potentiometer on the EconoMi$er IV controller. When
using this mode of changeover control, turn the enthalpy set
point potentiometer fully clockwise to the D setting.

Table 4 — 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

sensor.

**33ZCASPCO2 is an accessory aspirator box required for duct-mounted

applications.

††CRCBDIOX005A00 is an accessory that contains both 33ZCSENCO2 and

33ZCASPCO2 accessories.

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*

for DCV

Control using a

Wall-Mounted

Sensor

33ZCSENCO2

for DCV

Control using a

Duct-Mounted

Sensor

33ZCSENCO2†

and

33ZCASPCO2**

CRCBDIOX005A00††

SUPPLY AIR
TEMPERATURE
SENSOR
MOUNTING
LOCATION

SUPPLY AIR
TEMPERATURE
SENSOR

Fig. 26 — Supply Air Sensor Location

Fig. 27 — EconoMi$er IV Controller Potentiometer

and LED Locations

ECONOMI$ER IV

ECONOMI$ER IV
CONTROLLER

GROMMET

RETURN AIR
SENSOR

RETURN DUCT
(FIELD-PROVIDED)

Fig. 29 — Return Air Temperature or Enthalpy

Sensor Mounting Location

LED ON

LED OFF

100

DEGREES FAHRENHEIT

Fig. 28 — Outdoor Air Temperature

Changeover Set Points