Bryant 548J - Manual (Page 50)

50
SUPPLY AIR
TEMPERATURE
SENSOR
MOUNTING
LOCATION
SUPPLY AIR
TEMPERATURE
SENSOR
C06033
Fig. 71 -- Supply Air Sensor Location
The temperature sensor looks like an eyelet terminal with
wires running to it. The sensor is located in the “crimp
end” and is sealed from moisture.
Outdoor Air Lockout Sensor
The EconoMi$er IV is equipped with an ambient
temperature lockout switch located in the outdoor
airstream which is used to lock out the compressors below
a 42_F (6_C) ambient temperature. (See Fig. 66.)
EconoMi$er IV Control Modes
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. See
Fig. 69 for wiring information.
Determine the EconoMi$er IV control mode before set up
of the control. Some modes of operation may require
different sensors. (See Table 22.) The EconoMi$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 22 – EconoMi$er IV Sensor Usage
APPLICATION
ECONOMI$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**
O
R CRCBDIOX005A00††
* 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 setpoint selected
on the control. If the outdoor-air temperature is above the
setpoint, the EconoMi$er IV will adjust the outside air
dampers to minimum position. If the outdoor-air
temperature is below the setpoint, the position of the
outside air dampers will be controlled to provided free
cooling using outdoor air. When in this mode, the LED
next to the free cooling setpoint potentiometer will be on.
The changeover temperature setpoint is controlled by the
free cooling setpoint potentiometer located on the control.
(See Fig. 72.) The scale on the potentiometer is A, B, C,
and D. See Fig. 73 for the corresponding temperature
changeover values.
C06034
Fig. 72 -- EconoMi$er IV Controller Potentiometer
and LED Locations
LED ON
LED ON
LED ON
LED ON
LED OFF
19
18
LED OFF
LED OFF
LED OFF
17
16
15
14
13
12
11
10
9
40 45 50 55 60 65 70 75 80 85 90 95 100
DEGREES FAHRENHEIT
mA
D
C
B
A
C06035
Fig. 73 -- Outside Air Temperature Changeover
Setpoints
548J