OM 1280-2 • MICROTECH UNIT CONTROLLER 62 www.DaikinApplied.com
Troubleshooting Temperature Sensors
with increasing temperature. The element has a reference
resistance of 10K ohms at 77°F (25°C). Each element is
calibrated as highlighted in Table 26 below.
Use the following procedure to troubleshoot a suspect sensor.
1. Disconnect both sensor leads from the UVC.
2. Using some other calibrated temperature sensing device,
take a temperature reading at the sensor location.
3. Use the temperature reading from Step 2 to determine
the expected sensor resistance from Table 26.
4. Using a calibrated ohmmeter, measure the actual
resistance across the two sensor leads.
5. Compare the expected resistance to the actual
resistance.
6. If the actual resistance value deviates substantially
(more than 10%) from the expected resistance, replace
the sensor.
Table 26: Temperature Versus Resistance
°F °C Ohms °F °C Ohms °F °C Ohms °F °C Ohms °F °C Ohms
-39 -39.44 323839 11 -11.67 60592 61 16.11 14925 111 43.89 4561 161 71.67 1655
-37 -38.33 300974 13 -10.56 57017 63 17.22 14180 113 45.00 4367 163 72.78 1594
-35 -37.22 279880 15 -9.44 53647 65 18.33 13478 115 46.11 4182 165 73.89 1536
-33 -36.11 260410 17 -8.33 50526 67 19.44 12814 117 47.22 4006 167 75.00 1480
-31 -35.00 242427 19 -7.22 47606 69 20.56 12182 119 48.33 3838 169 76.11 1427
-29 -33.89 225809 21 -6.11 44874 71 21.67 11590 121 49.44 3679 171 77.22 1375
-27 -32.78 210443 23 -5.00 42317 73 22.78 11030 123 50.56 3525 173 78.33 1326
-25 -31.67 196227 25 -3.89 39921 75 23.89 10501 125 51.67 3380 175 79.44 1279
-23 -30.56 183068 27 -2.78 37676
77 25.00 10000
127 52.78 3242 177 80.56 1234
-21 -29.44 170775 29 -1.67 35573 79 26.11 9526 129 53.89 3111 179 81.67 1190
-19 -28.33 159488 31 -0.56 33599 81 27.22 9078 131 55.00 2985 181 82.78 1149
-17 -27.22 149024 33 0.56 31732 83 28.33 8653 133 56.11 2865 183 83.89 1109
-15 -26.11 139316 35 1.67 29996 85 29.44 8251 135 57.22 2751 185 85.00 1070
-13 -25.00 130306 37 2.78 28365 87 30.56 7866 137 58.33 2642 187 86.11 1034
-11 -23.89 121939 39 3.89 26834 89 31.67 7505 139 59.44 2538
-9 -22.78 114165 41 5.00 25395 91 32.78 7163 141 60.56 2438
-7 -21.67 106939 43 6.11 24042 93 33.89 6838 143 61.67 2343
-5 -20.56 100218 45 7.22 22770 95 35.00 6530 145 62.78 2252
-3 -19.44 93909 47 8.33 21573 97 36.11 6238 147 63.89 2165
-1 -18.33 88090 49 9.44 20446 99 37.22 5960 149 65.00 2082
1 -17.22 82670 51 10.56 19376 101 38.33 5697 151 66.11 2003
3 -16.11 77620 53 11.67 18378 103 39.44 5447 153 67.22 1927
5 -15.00 72911 55 12.78 17437 105 40.56 5207 155 68.33 1855
7 -13.89 68518 57 13.89 16550 107 41.67 4981 157 69.44 1785
9 -12.78 64419 59 15.00 15714 109 42.78 4766 159 70.56 1718
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