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53
Supply Air Temperature (SAT) Sensor
The supply air temperature sensor is a 3 K thermistor
located at the inlet of the indoor fa n. (See Fig. 65.) 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.
SUPPLY AIR
TEMPERATURE
SENSOR
MOUNTING
LOCATION
SUPPLY AIR
TEMPERATURE
SENSOR
C06033
Fig. 65 -- Supply Air Sensor Locat ion
The temperature sensor looks li ke an eyelet termina l with
wires running to it. The sensor is located in the “crimp
end” and is sealed from moisture.
Outdoor Air Lockout Sensor
The E conoMi$er IV i s equipped with an ambient
temperature lockout switch located in the outdoor
airstream which is used to loc k out the compressors below
a42_F(6_C) ambient temperature. (See Fig. 60.)
EconoMi$e r IV Control
Modes
IMPORTANT: T he 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. 63 for wiring information.
Determine t he EconoMi$er IV control mode before set up
of the control . Some modes of opera tion may require
different sensors. (See Table 22.) The E conoMi$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$er IV with outdoor air dry
bulb changeover control. Additional accessories can be
added to allow for different types of changeover control
and operati on of the EconoMi$er IV and unit.
Outdoor Dry Bulb Changeover
The standard controller is shipped from the factory
configure d for outdoor dry bulb changeover control. The
outdoor air and supply air temperat ure se nsors are
included a s standard. For this control mode, the outdoor
temperature is compared to an adjustable setpoi nt selected
on the control. If the outdoor-air temperature is above the
setpoint, the EconoMi$er IV will adjust the outside air
dampers to minimum position. If the outdoor-air
temperature is below the setpoint, the position of the
outside air da mpers will be controlled to provided free
cooling using outdoor air. When in this mode, the LED
next to the free cooling setpoint potentiometer will be on.
The changeover temperature setpoi nt is controlled by the
free cooling setpoint potentiometer located on the control.
(See Fig. 66.)
The scale on the potentiometer is A, B, C, and D. See Fig.
63 for the c orresponding temperature changeover values.
C06034
Fig. 66 -- EconoMi$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. 67 -- Outside Air Temperature Changeover
Setpoints
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
STATICPRESSURE (in. wg)
FLOW IN CUBIC FEET PER MINUTE (cfm)
C06031
Fig. 68 -- Outdoor--Air Damper Leakage
580J