26
RSMD2R Technical Guide
TROUBLESHOOTING
Copeland
®
Discharge Thermistor Temperature Sensor Testing
Copeland
®
Discharge Thermistor
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 confirm that the
sensor is operating correctly per the table. Please follow the notes
and instructions the appear after the chart when checking sensors.
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 4.98 VDC, then the sensor or wiring is
“open.” If the voltage is less than 0.38 VDC, then the sensor or
wiring is shorted.
Discharge Thermistor Temperature/Resistance
Temp
(ºF)
Temp
(ºC)
Resistance
(K Ohms)
Voltage @
Input (VDC)
Temp
(ºF)
Temp
(ºC)
Resistance
(Ohms)
Voltage @
Input
(VDC)
-40
-40
2889.60
4.98
167
75
12.73
2.80
-31
-35
2087.22
4.97
176
80
10.79
2.59
-22
-30
1522.20
4.96
185
85
9.20
2.39
-13
-25
1121.44
4.95
194
90
7.87
2.19
-4
-20
834.72
4.94
203
95
6.77
2.01
5
-15
627.28
4.92
212
100
5.85
1.84
14
-10
475.74
4.89
221
105
5.09
1.68
23
-5
363.99
4.86
230
110
4.45
1.53
323
0
280.82
4.82
239
115
3.87
1.39
41
5
218.41
4.77
248
120
3.35
1.25
50
10
171.17
4.72
257
125
2.92
1.12
59
15
135.14
4.65
266
130
2.58
1.02
68
20
107.44
4.57
275
135
2.28
0.92
77
25
86.00
4.47
284
140
2.02
0.83
86
30
69.28
4.36
293
145
1.80
0.76
95
35
56.16
4.24
302
150
1.59
0.68
104
40
45.81
4.10
311
155
1.39
0.61
113
45
37.58
3.94
320
160
1.25
0.55
122
50
30.99
3.77
329
165
1.12
0.50
131
55
25.68
3.59
338
170
1.01
0.45
140
60
21.40
3.40
347
175
0.92
0.42
149
65
17.91
3.20
356
180
0.83
0.38
158
70
15.07
3.00
Table 5: Discharge Thermistor Temperature/Resistance
Summary of Contents for RSMD2R
Page 1: ...RSMD2R Technical Guide...
