Appendix a - system configurations, Temperature sensor testing, Vcc-x controller technical guide 78 – Orion System VCC-X Controller User Manual
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APPENDIX A - SYSTEM CONFIGURATIONS
VCC-X Controller Technical Guide
78
Thermistor Sensor Testing Instructions
Use the resistance column to check the thermistor sensor while
disconnected from the controllers (not powered).
Use the voltage column to check sensors while connected to powered
controllers. Read voltage with meter set on DC volts. Place the “-”
(minus) lead on GND terminal and the “+” (plus) lead on the sensor
input terminal being investigated.
If the voltage is above 4.88 VDC, then the sensor or wiring is “open.”
If the voltage is less than 0.05 VDC, then the sensor or wiring is
shorted.
Temperature Sensor Testing
Space, Outdoor Air or Return Air
Temperature Sensor Testing
The following sensor voltage and resistance table is provided to aid
in checking sensors that appear to be operating incorrectly. Many
system operating problems can be traced to incorrect sensor wiring.
Be sure all sensors are wired per the wiring diagrams in this manual.
If the sensors still do not appear to be operating or reading correctly,
check voltage and/or resistance to confi rm that the sensor is operating
correctly per the tables. Please follow the notes and instructions that
appear after the chart when checking sensors.
Temperature – Resistance – Voltage for Type
III 10 K Ohm Thermistor Sensors
Temp
(ºF)
Temp
(ºC)
Resistance
(Ohms)
Voltage @
Input (VDC)
-10
-23.33
93333
4.51
-5
-20.55
80531
4.45
0
-17.77
69822
4.37
5
-15
60552
4.29
10
-12.22
52500
4.2
15
-9.44
45902
4.1
20
-6.66
40147
4.002
25
-3.88
35165
3.891
30
-1.11
30805
3.773
35
1.66
27140
3.651
40
4.44
23874
3.522
45
7.22
21094
3.39
50
10
18655
3.252
52
11.11
17799
3.199
54
12.22
16956
3.143
56
13.33
16164
3.087
58
14.44
15385
3.029
60
15.55
14681
2.972
62
16.66
14014
2.916
64
17.77
13382
2.861
66
18.88
12758
2.802
68
20
12191
2.746
69
20.55
11906
2.717
70
21.11
11652
2.691
71
21.66
11379
2.661
72
22.22
11136
2.635
73
22.77
10878
2.605
Table 6: Temperature/Resistance for Type III 10K
Ohm Thermistor Sensors
Temperature – Resistance – Voltage for Type
III 10 K Ohm Thermistor Sensors
Temp
(ºF)
Temp
(ºC)
Resistance
(Ohms)
Voltage @
Input (VDC)
74
23.33
10625
2.576
75
23.88
10398
2.549
76
24.44
10158
2.52
77
25
10000
2.5
78
25.55
9711
2.464
80
26.66
9302
2.41
82
27.77
8893
2.354
84
28.88
8514
2.3
86
30
8153
2.246
88
31.11
7805
2.192
90
32.22
7472
2.139
95
35
6716
2.009
100
37.77
6047
1.884
105
40.55
5453
1.765
110
43.33
4923
1.65
115
46.11
4449
1.54
120
48.88
4030
1.436
125
51.66
3656
1.339
130
54.44
3317
1.246
135
57.22
3015
1.159
140
60
2743
1.077
145
62.77
2502
1.001
150
65.55
2288
0.931
Table 6, cont.: Temperature/Resistance for Type III
10K Ohm Thermistor Sensors