54
CHECK SENSOR ACCURACY
Place the sensor in a medium of known temperature and com-
pare that temperature to the measured reading. The thermome-
ter used to determine the temperature of the medium should be
of laboratory quality with 0.5F (0.25C) graduations. The sen-
sor in question should be accurate to within 2F (1.2C).
Note that the PIC 6 control module, MAINTENANCE menu,
offers a water temperature sensor calibration feature where the
sensor temperature can be offset. To use this feature, place the
sensor at 32°F (0C) or other known temperature. Read the raw
temperature and calculate offset based on the reading seen in the
TEMP_CAL menu. Enter and execute the offset, which cannot
exceed ± 2F (1.2C).
See Fig. 3-5 for sensor locations. The sensors are immersed di-
rectly in the refrigerant or water circuits. When installing a new
sensor, apply a pipe sealant or thread sealant to the sensor
threads.
An additional thermistor, factory installed in the bottom of the
cooler barrel, is displayed as Evap Refrig Liquid Temp on the
TEMPERATURES display screen. This thermistor provides
additional protection against a loss of water flow.
DUAL TEMPERATURE SENSORS
For servicing convenience, there are 2 redundant sensors each on
the bearing and motor temperature sensors. If one of the sensors
is damaged, the other can be used by simply moving a wire. The
number 2 terminal in the sensor terminal box is the common
line. To use the second sensor, move the wire from the number 1
position to the number 3 position. See Fig. 48-50.
Fig. 48 — 19XR2-E Thrust-Bearing Sensor Fig. 49 — Bearing 1 Sensor Wiring from Back of
Terminal Block (XR6/7 only)
Fig. 50 — Bearings 2-4 Sensor Wiring from Back of Terminal Block (XR6/7 only)
BEARING #1
TERMINAL BLOCK LOCATED
ON END OF MOTOR COVER
TERMINAL BLOCKS LOCATED
BETWEEN HEATER AND OIL PUMP
a19-2125
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