© 2011
D 406 - 12/11
8 of 48
Mounting the Universal Sensor
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Note: These sensors are designed to mount on a pipe or in a temperature
immersion well.
The Universal Sensor should be placed downstream of a pump or after an elbow
or similar fitting. This is especially important 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.
Strapped to Pipe
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.
Immersion Well
If a Universal Sensor is mounted onto 1” (25 mm) diameter L type copper pipe,
there is approximately an 8 second delay between a sudden change in water
temperature and the time the sensor measures the temperature change. This
delay increases considerably when mild steel (black iron) pipe is used. In general,
it is recommended that a temperature well be used for steel pipe of diameter
greater than 1-1/4” (32 mm). Temperature wells are also recommended when
large diameter pipes are used and fluid stratification is present.
Conduit Connection
The Universal Sensor and Universal Sensor Enclosure 080 (sold separately) are
specifically designed to mount onto a 3/8” (10 mm) ID temperature well that is
supplied with an end groove. To install the well, plumb a ‘T’ into the pipe and fix
the well into the ‘T’. The 080 enclosure has a 7/8” (22 mm) back knockout that
must be removed and fitted over the temperature well. The universal sensor is
then inserted into the well and the retaining clip supplied with the enclosure is
snapped onto the well end groove. If the well has a threaded end, the installer
must supply a standard threaded conduit retaining ring. The two wires from the
sensor are connected to the terminal block provided in the enclosure. The other
side of the terminal block is used to connect wires from the control.
A good quality test meter capable of measuring up to 5,000 kΩ
(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.
Testing the Sensor Wiring
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
139,403
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
Bottom of
Enclosure 080
Universal
Sensor
Cable Tie
Sensor Well
Retaining
Clip
Universal
Sensor
