Slant/Fin SC-3 User Manual
Page 4
5
SC-3 Controller
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
Ω (1 kΩ = 1000 Ω) 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
Temperature
Resistance
Temperature
Resistance
Temperature
Resistance
˚F
˚C
˚F
˚C
˚F
˚C
˚F
˚C
-50
-46
490,813
20
-7
46,218
90
32
7,334
160
71
1,689
-45
-43
405,710
25
-4
39,913
95
35
6,532
165
74
1,538
-40
-40
336,606
30
-1
34,558
100
38
5,828
170
77
1,403
-35
-37
280,279
35
2
29,996
105
41
5,210
175
79
1,281
-30
-34
234,196
40
4
26,099
110
43
4,665
180
82
1,172
-25
-32
196,358
45
7
22,763
115
46
4,184
185
85
1,073
-20
-29
165,180
50
10
19,900
120
49
3,760
190
88
983
-15
-26
139,402
55
13
17,436
125
52
3,383
195
91
903
-10
-23
118,018
60
16
15,311
130
54
3,050
200
93
829
-5
-21
100,221
65
18
13,474
135
57
2,754
205
96
763
0
-18
85,362
70
21
11,883
140
60
2,490
210
99
703
5
-15
72,918
75
24
10,501
145
63
2,255
215
102
648
10
-12
62,465
80
27
9,299
150
66
2,045
220
104
598
15
-9
53,658
85
29
8,250
155
68
1,857
225
107
553
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.
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.