Resistance Check; Voltage Drop Check - Carrier 19DV Series Installation, Operation And Maintenance Instructions

temperature by measuring voltage drop; if the controls are powered off, determine sensor temperature by
measuring resistance. Compare the readings to the values listed in Table 22.

10.4 Resistance Check

Turn off the control power from the module, disconnect the terminal plug of the sensor in question. With a digital
ohmmeter, measure sensor resistance between receptacles as designated by the wiring diagram. The resistance
and corresponding temperature are listed in table 22. Check the resistance of both wires to ground .This
resistance should be infinite.

10.5 Voltage Drop Check

The voltage drop across any energized sensor can be measured with a digital voltmeter while the control is
energized. Table 22 lists the relationship between temperature and sensor voltage drop (dv volts measured
across the energized sensor). Exercise care when measuring voltage to prevent damage to the sensor leads,
connector plugs, and modules. Sensors should also be checked at the sensor plugs.
CAUTION: Relieve all refrigerant pressure or drain the water before removing any thermowell threaded into the
refrigerant pressure boundary. Failure to do so could result in personal injury and equipment damage.
Pic
Temperature voltage Resistance
(°C) drop (V)
-33 4.722
-32 4.706
-31 4.688
-30 4.67
-29 4.65
-28 4.63
-27 4.608
-26 4.586
-25 4.562
-24 4.538
-23 4.512
-22 4.486
-21 4.458
-20 4.429
-19 4.399
-18 4.368
-17 4.336
-16 4.303
-15 4.269
-14 4.233
-13 4.196
-12 4.158
-11 4.119
-10 4.079
-9 4.037
-8 3.994
-7 3.951
-6 3.906
-5 3.861
-4 3.814
-3 3.765
-2 3.716
-1 3.667
0 3.617
1 3.565
2 3.512
3 3.459
4 3.406
5 3.353
6 3.298
T Pic v.d.
(Ohms) (°C) (V)
105 616 7 3.242
99 640 8 3.185
93 928 9 3.129
88 480 10 3.074
83 297 11 3.016
78 377 12 2.959
73 722 13 2.901
69 332 14 2.844
65 205 15 2.788
61 343 16 2.73
57 745 17 2.672
54 411 18 2.615
51 341 19 2.559
48 536 20 2.503
45 819 21 2.447
43 263 22 2.391
40 858 23 2.335
38 598 24 2.28
36 476 25 2.227
34 484 26 2.173
32 613 27 2.12
30 858 28 2.067
29 211 29 2.015
27 663 30 1.965
26 208 31 1.914
24 838 32 1.865
23 545 33 1.816
22 323 34 1.768
21 163 35 1.721
20 083 36 1.675
19 062 37 1.629
18 097 38 1.585
17 185 39 1.542
16 325 40 1.499
15 513 41 1.457
14 747 42 1.417
14 023 43 1.377
13 341 44 1.338
12 696 45 1.3
12 087 46 1.263
Table 22 – Voltage drop and resistance vs temperature
Pic
R T v.d.
(Ohms) (°C) (V)
11 510 47 1.227
10 963 48 1.192
10 444 49 1.158
9 949 50 1.124
9 486 51 1.091
9 046 52 1.06
8 628 53 1.029
8 232 54 0.999
7 855 55 0.969
7 499 56 0.941
7 160 57 0.913
6 839 58 0.887
6 535 59 0.861
6 246 60 0.835
5 972 61 0.811
5 711 62 0.787
5 463 63 0.764
5 226 64 0.741
5 000 65 0.719
4 787 66 0.698
4 583 67 0.677
4 389 68 0.657
4 204 69 0.638
4 028 70 0.619
3 861 71 0.601
3 701 72 0.583
3 549 73 0.566
3 404 74 0.549
3 266 75 0.533
3 134 76 0.518
3 008 77 0.503
2 888 78 0.488
2 773 79 0.474
2 663 80 0.46
2 559 81 0.447
2 459 82 0.434
2 363 83 0.422
2 272 84 0.41
2 184 85 0.398
2 101 86 0.387
R T Pic v.d.
(Ohms) (°C) (V)
2 021 87 0.376
1 944 88 0.365
1 871 89 0.355
1 801 90 0.344
1 734 91 0.335
1 670 92 0.325
1 609 93 0.316
1 550 94 0.308
1 493 95 0.299
1 439 96 0.291
1 387 97 0.283
1 337 98 0.275
1 290 99 0.267
1 244 100 0.26
1 200 101 0.253
1 158 102 0.246
1 117 103 0.239
1 079 104 0.233
1 041 105 0.227
1 006 106 0.221
971 107 0.215
938 108 0.21
906 109 0.205
876 110 0.198
846 111 0.193
818 112 0.188
791 113 0.183
765 114 0.178
740 115 0.174
715 116 0.17
692 117 0.165
670 118 0.161
648 119 0.157
628 120 0.153
608
588
570
552
535
518
R
(Ohms)
502
487
472
458
444
431
418
405
393
382
371
360
349
339
330
320
311
302
294
286
278
270
262
255
248
242
235
229
223
217
211
205
200
195
109