6-22
T--317
Table 6-1 Sensor Temperature/Resistance Chart
Temperature
Centigrade
Temperature
Fahrenheit
Resistance
(Ohms)
RRS, RTS, SRS and STS:
0
32
32,650
±
91
25
77
10,000
±
50
AMBS and DTS
0
32
32,650 + 1720
-- 1620
25
77
10,000 + 450
-- 430
Due to the variations and inaccuracies in ohmmeters,
thermometers or other test equipment, a reading
within 2% of the chart value would indicate a good
sensor. If a sensor is defective, the resistance read-
ing will usually be much higher or lower than the resis-
tance values given.
6.23.2 Sensor Replacement
a. Turn unit power OFF and disconnect power supply.
b. For two wire sensors, cut cable 5 cm (2 inches) from
shoulder of defective sensor and discard the defec-
tive sensor only. For three wire sensors cut at 23 cm
(9 inches). Slide the cap and grommet off well
mounted sensor and save for possible reuse.
Do not
cut the grommet.
c. If required, prepare the replacement sensor by cut-
ting sensor wire(s) back 40 mm (1-1/2 inch). For three
wire sensors the black wire should be cut at the
middle length and the red/white wire cut to the shorter
length. (See Figure 6-23.)
Sensor
40 mm (1 1/2 inch)
6.3 mm (1/4 inch)
Mounting Stud Type
Sensor
40 mm (1-1/2 inches)
6.3 mm (1/4 inch)
Bulb Type
Figure 6-23 Sensor Types
d. Prepare the cables by cutting wires to the opposite of
the sensor. (See Figure 6-24.)
When installing a single wire color two wire sensor,
cut one wire of existing two wire cable 40 mm (1-1/2
inch) shorter than the other wire.
When replacing two single sensors with a combina-
tion (three wire) sensor, the black wires of the cables
should be cut to the same length and the red wire of
one cable cut to the shorter length.
When replacing a original three wire sensor, cut the
black wire to the middle length and the red wire to the
shorter length.
e. Strip back insulation on all wiring 6.3 mm (1/4 inch).
f. Slide a large piece of heat shrink tubing over the
cable, and place small pieces of heat shrink tubing,
one over each wire, before adding crimp fittings as
shown in Figure 6-24.
g. If required, slide the cap and grommet assembly onto
the replacement sensor. If the replacement sensor is
of a larger diameter than the original, a different grom-
met may be required.
h. Slip crimp fittings over dressed wires (keeping wire
colors together). Make sure wires are pushed into
crimp fittings as far as possible and crimp with crimp-
ing tool.
i. Solder spliced wires with a 60% tin and 40% lead
Rosincore solder.
j. Slide heat shrink tubing over splice so that ends of
tubing cover both ends of crimp as shown in
Figure 6-24.
k. Heat tubing to shrink over splice. Make sure all seams
are sealed tightly against the wiring to prevent mois-
ture seepage.
l. Slide large heat shrink tubing over both splices and
shrink.
CAUTION
Do not allow moisture to enter wire splice
area as this may affect the sensor resis-
tance.
m.Reinstall sensor, refer to paragraph 6.23.3.
NOTE
The P5 Pre-Trip test must be run to inactivate
probe alarms (refer to paragraph 4.8).
