Carrier 48TC 17 Series Service And Maintenance Instructions page 53

EconoMi$er IV Standard Sensors
Table 19 provides a summary of the EconoMi$er IV
Input/Output logic. A functional view of the EconoMi$er
is shown in Fig. 64. Typical settings, sensor ranges, and
jumper positions are also shown. An EconoMi$er IV
simulator program is available to help with EconoMi$er
IV training and troubleshooting.
Outdoor Air Temperature (OAT) Sensor
The outdoor air temperature sensor (HH57AC074) is a 10
to 20 mA device used to measure the outdoor-air
temperature. The outdoor-air temperature is used to
determine when the EconoMi$er IV can be used for free
cooling. The sensor is
EconoMi$er IV in the outdoor airstream. See Fig. 65. The
operating range of temperature measurement is 40_ to
100_F (4_ to 38_C). See Fig. 67.
Supply Air Temperature (SAT) Sensor
The supply air temperature sensor is a 3K thermistor
located at the inlet of the indoor fan. See Fig. 65. This
sensor is factory installed. The operating range of
temperature measurement is 0° to 158_F (−18_ to 70_C).
See Table 65 for sensor temperature/resistance values.
The temperature sensor looks like an eyelet terminal with
wires running to it. The sensor is located in the "crimp
end" and is sealed from moisture.
Outdoor Air Lockout Sensor
The EconoMi$er IV is equipped with an ambient
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. 61.
Fig. 64 − EconoMi$er IV Functional View
factory-installed on the
SUPPLY
AIR TEMPERATURE
SENSOR MOUNTING
LOCATION
SUPPLY AIR
TEMPERATURE
SENSOR
(SEALED
INSIDE CRIMP
END)
Fig. 65 − Supply Air Sensor Location
EconoMi$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. 63 for wiring information.
Determine the EconoMi$er IV control mode before set up
of the control. Some modes of operation may require
different sensors. The EconoMi$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. See Table 20.
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