Bryant DURAPAC 580F User Manual
Page 17
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C. EconoMi$er IV Standard Sensors
Outdoor Air Temperature (OAT) Sensor
The outdoor air temperature sensor (HH57AC074) is a 10 to
20 mA device used to measure the outdoor-air temperature.
The outdoor-air temperature is used to determine when
the EconoMi$er IV can be used for free cooling. The sensor is
factory-installed on the EconoMi$er IV in the outdoor
airstream. See Fig. 16. The operating range of temperature
measurement is 40 to 100 F.
Supply Air Temperature (SAT) Sensor
The supply air temperature sensor is a 3 K thermistor
located at the inlet of the indoor fan. See Fig. 26. This
sensor is factory installed. The operating range of tempera-
ture measurement is 0° to 158 F. See Table 3 for sensor
temperature/resistance values.
The temperature sensor looks like an eyelet terminal with
wires running to it. The sensor is located in the “crimp end”
and is sealed from moisture.
Outdoor Air Lockout Sensor
The EconoMi$er IV is equipped with an ambient tempera-
ture lockout switch located in the outdoor air stream which
is used to lockout the compressors below a 42 F ambient tem-
perature. See Fig. 16.
Table 3 — Supply Air Sensor
Temperature/Resistance Values
D. 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 sensors.
Refer to Table 4. The EconoMi$er IV is supplied from the fac-
tory with a supply air temperature sensor and an outdoor air
temperature sensor. This allows for operation of the
EconoMi$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$er
IV and unit.
Outdoor Dry Bulb Changeover
The standard controller is shipped from the factory config-
ured for outdoor dry bulb changeover control. The outdoor
air and supply air temperature sensors are included as
standard. For this control mode, the outdoor temperature is
compared to an adjustable set point selected on the control.
If the outdoor-air temperature is above the set point, the
EconoMi$er IV will adjust the outdoor air dampers to mini-
mum 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. 27. The scale on the potentiometer is
A, B, C, and D. See Fig. 28 for the corresponding temperature
changeover values.
Differential Dry Bulb Control
For differential dry bulb control the standard outdoor dry
bulb sensor is used in conjunction with an additional acces-
sory dry bulb sensor (part number CRTEMPSN002A00). The
accessory sensor must be mounted in the return airstream.
See Fig. 29. Wiring is provided in the EconoMi$er IV wiring
harness. See Fig. 22.
TEMPERATURE (F)
RESISTANCE (ohms)
–58
200,250
–40
100,680
–22
53,010
–4
29,091
14
16,590
32
9,795
50
5,970
68
3,747
77
3,000
86
2,416
104
1,597
122
1,080
140
746
158
525
176
376
185
321
194
274
212
203
230
153
248
116
257
102
266
89
284
70
302
55
0
500
1000
1500
2000
2500
0.05
0.15
0.25
STATIC PRESSURE (in. wg)
FLOW IN CUBIC FEET
PER MINUTE (cfm)
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)
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 MINUTE (cfm)
Fig. 23 — Barometric Flow Capacity
Fig. 24 — Outdoor-Air Damper Leakage
Fig. 25 — Return-Air Pressure Drop