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5
The Universal Sensor can be
strapped directly to the pipe using
the cable tie provided. Insulation
should be placed around the sensor
to reduce the effect of air currents on
the sensor measurement. The flat
portion of the sensor should be mounted
against the pipe.
WIRING AND TESTING THE SENSOR
WARNING: Do not run sensor wires close to and parallel to telephone or power cables. If the sensor wires are located in an area with
strong sources of electromagnetic interference, shielded cable or twisted pair should be used or the wires can be run in a grounded metal
conduit. If using shielded cable, the shield wire should be connected to the Com Sen terminal on the control and not to earth ground.
• It is necessary to connect 18 AWG wire to the two sensor wires. Wire nuts can be used to hold the wires together.
• Follow the sensor testing instructions that follow and then connect the wires to the control.
SENSOR TESTING INSTRUCTIONS
A good quality test meter capable of measuring up to 5,000 k (1 k = 1000 ) is required to measure the sensor resistance. In addition
to this, the actual temperature must be measured with either a good quality digital thermometer, or if a thermometer is not available,
a second sensor can be placed alongside the one to be tested and the readings compared.
First measure the temperature using the thermometer and then measure the resistance of the sensor at the control. The wires from the
sensor must not be connected to the control while the test is performed. Using the chart below, estimate the temperature measured by
the sensor. The sensor and thermometer readings should be close. If the test meter reads a very high resistance, there may be a broken
wire, a poor wiring connection or a defective sensor. If the resistance is very low, the wiring may be shorted, there may be moisture in
the sensor or the sensor may be defective. To test for a defective sensor, measure the resistance directly at the sensor location.
Do not apply voltage to a sensor at any time as damage to the sensor may result.
Temperature
Resistance
˚F
˚C
-50
-46
490,813
-45
-43
405,710
-40
-40
336,606
-35
-37
280,279
-30
-34
234,196
-25
-32
196,358
-20
-29
165,180
-15
-26
139,402
-10
-23
118,018
-5
-21
100,221
0
-18
85,362
5
-15
72,918
10
-12
62,465
15
-9
53,658
Temperature
Resistance
˚F
˚C
20
-7
46,218
25
-4
39,913
30
-1
34,558
35
2
29,996
40
4
26,099
45
7
22,763
50
10
19,900
55
13
17,436
60
16
15,311
65
18
13,474
70
21
11,883
75
24
10,501
80
27
9,299
85
29
8,250
The Universal Sensor should be placed
downstream of a pump or after an elbow
or similar fitting. This is especially impor-
tant if large diameter pipes are used as
the thermal stratification within the pipe
can result in erroneous sensor readings.
Proper sensor location requires that the
fluid is thoroughly mixed within the pipe
before it reaches the sensor.
Temperature
Resistance
˚F
˚C
90
32
95
35
100
38
105
41
110
43
115
46
120
49
125
52
130
54
135
57
140
60
145
63
150
66
155
68
SC-3 Controller
Temperature
˚F
˚C
7,334
160
71
6,532
165
74
5,828
170
77
5,210
175
79
4,665
180
82
4,184
185
85
3,760
190
88
3,383
195
91
3,050
200
93
2,754
205
96
2,490
210
99
2,255
215
102
2,045
220
104
1,857
225
107
Resistance
1,689
1,538
1,403
1,281
1,172
1,073
983
903
829
763
703
648
598
553
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