Slant/Fin SC-3 - 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.