Bryant 548J Service And Maintenance Instructions page 50

SUPPLY AIR
TEMPERATURE
SENSOR
MOUNTING
LOCATION
SUPPLY AIR
TEMPERATURE
SENSOR
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
The optional EconoMi$er2 does not include
IMPORTANT:
a controller. The EconoMi$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$er IV Sensor Usage
ECONOMI$ER IV WITH OUTDOOR AIR DRY
APPLICATION
Accessories Required
Outdoor Air None. The outdoor air dry bulb sensor is
Dry Bulb
Differential
Dry Bulb
Single Enthalpy
Differential
HH57AC078 and CRENTDIF004A00*
Enthalpy
CO for DCV
2
Control using a
Wall-Mounted
CO Sensor
2
CO for DCV
2
Control using a 33ZCSENCO2† and
Duct-Mounted 33ZCASPCO2**
CO Sensor
2
* 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
** 33ZCASPCO2 is an accessory aspirator box required for
duct-mounted applications.
†† CRCBDIOX005A00 is an accessory that contains both
33ZCSENCO2 and 33ZCASPCO2 accessories.
C06033
BULB SENSOR
factory installed.
CRTEMPSN002A00*
HH57AC078
33ZCSENCO2
O
CRCBDIOX005A00††
R
sensor.
2
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$er IV will adjust the outside air
dampers to minimum position. If the outdoor-air
temperature is below the setpoint, the position of the
outside air dampers will be controlled to provided free
cooling using outdoor air. When in this mode, the LED
next to the free cooling setpoint potentiometer will be on.
The changeover temperature setpoint is controlled by the
free cooling setpoint potentiometer located on the control.
(See Fig. 72.) The scale on the potentiometer is A, B, C,
and D. See Fig. 73 for the corresponding temperature
changeover values.
Fig. 72 - - EconoMi$er IV Controller Potentiometer
and LED Locations
19
LED ON
18
D
17
LED ON
16 LED OFF
15
14
LED OFF
13
12
11
10
9
40 45 50 55 60 65
DEGREES FAHRENHEIT
Fig. 73 - - Outside Air Temperature Changeover
Setpoints
50
C06034
C
LED ON
B
LED ON
LED OFF
A
LED OFF
100
70 75 80 85 90 95
C06035