Bryant 580J*04--12, Service And Maintenance Instructions

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Fig. 43 -- EconoMi$er IV Functional View
EconoMi$er IV
Table 15 provides a summary of EconoMi$er IV.
Troubleshooting instructions are enclosed.
A functional view of the EconoMi$er is shown in Fig. 43.
Typical settings, sensor ranges, and jumper positions are
also shown. An EconoMi$er IV simulator program is
available from Bryant to help with EconoMi$er IV
training and troubleshooting.
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. 44.)
The operating range of temperature measurement is 40
_
to
100
_
F (4
_
to 38
_
C).
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. 44.) This
sensor is factory installed. The operating range of
temperature measurement is 0
°
to 158
_
F (--18
_
to 70
_
C).
See Table 16 for sensor temperature/resistance values.
Table 16 – Thermistor Resistance vs Temperature
Values for Space Temperature Sensor, Supply Air
Temperature Sensor, and Outdoor Air Temperature
Sensor
TEMP
(C)
TEMP
(F)
RESISTANCE
(Ohms)
---40 ---40 335,651
---35 ---31 242,195
---30 ---22 176,683
---25 ---13 130,243
---20 ---4 96,974
---15 5 72,895
---10 14 55,298
---5 23 42,315
0 32 32,651
5 41 25,395
10 50 19,903
15 59 15,714
20 68 12,494
25 77 10,000
30 86 8,056
35 95 6,530
40 104 5,325
45 113 4,367
50 122 3,601
55 131 2,985
60 140 2,487
65 149 2,082
70 158 1,752
580J