Orion System Dual Electronic Expansion Valve Module - Manual (Page 21)

Technical Guide
Dual Electronic Expansion Valve Module
21
Troubleshooting
Thermistor Sensor Testing Instructions
Use the resistance column to check the thermistor sensor while discon-
nected 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.
Coil Temperature Sensor Testing
The following sensor voltage and resistance table is provided to aid in
checking a coil temperature sensor that appears to be operating incor-
rectly. Many system operating problems can be traced to incorrect sensor
wiring. Be sure the sensor is wired per the wiring diagrams in this manual.
The Suction Pressure and Calculated Temperature is displayed in the
Module’s Status Screens. A voltage measurement can also be taken on
input for verifi cation.
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
Temperature – Resistance – Voltage for Type III
10 K Ohm Thermistor Sensors
Temp
(ºF)
Temp
(ºC)
Resistance
(Ohms)
Voltage @
Input (VDC)
72 22.22 11136 2.635
73 22.77 10878 2.605
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 5, cont.: Temperature/Resistance for Type III
10K Ohm Thermistor Sensors
Table 5: Temperature/Resistance for Type III 10K
Ohm Thermistor Sensors