Carrier 17/19EX - Manual (Page 257)

Check Sensor Accuracy
Place the sensor in a medium of a known temperature and compare that temperature to the
measured reading. The thermometer used to determine the temperature of the medium should
be of laboratory quality with 0.5° F (.25° C) graduations. The sensor in question should be
accurate to within 2° F (1.2° C).
See Figure 7 and Figure 8 for sensor locations. The sensors are immersed directly in the
refrigerant or water circuits. The wiring at each sensor is easily disconnected by unlatching the
connector. These connectors allow only one-way connection to the sensor. When installing a
new sensor, apply a pipe sealant or thread sealant to the sensor threads.
Dual Temperature Sensors
There are 2 sensing elements on each of the bearing temperature sensors (hermetic and
open-drive machines) and motor temperature sensors (hermetic machines only) for servicing
convenience. In case one of the dual sensors is damaged, the other one can be used by
moving a wire.
The number 1 terminal in the sensor terminal box is the common line. To use the second
sensor, move the wire from the number 2 position to the number 3 position.