Bryant 548J User Manual

Page 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*

for DCV

Control using a

Wall-Mounted

Sensor

33ZCSENCO2

for DCV

Control using a

Duct-Mounted

Sensor

33ZCSENCO2† and

33ZCASPCO2**

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

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 OFF

95 100

DEGREES FAHRENHEIT

C06035

Fig. 73 -- Outside Air Temperature Changeover

Setpoints

548J