Procedure for Checking Thermostat Sensors
Set the thermostat above water temperature (See temperature adjustment section) and observe system through one (1) complete cycle. Make sure system operates as desired.
To check the sensor assembly, compare the resistance of the sensor wires (either outside black to center wire with yellow marking) as measured by an ohmmeter to the water temperature as measured by an accurate thermometer. Thermistor resistance increases as the temperature decreases. The tables below show the correct sensor resistance at various temperatures. Both thermistors in the sensor assembly should have approximately the same readings. Replace the sensor if the ohm reading in the chart does not approximate the reading from the sensor at the temperature measured in the tank. Use a thermometer or thermocouple to measure the temperature from the hot water outlet or T&P valve.
In Degrees F
°F | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
40 | 26109 | 25400 | 24712 | 24045 | 23399 | 22771 | 22163 | 21573 | 21000 | 20445 |
50 | 19906 | 19383 | 18876 | 18383 | 17905 | 17440 | 16990 | 16553 | 16128 | 15715 |
60 | 15314 | 14925 | 14548 | 14180 | 13823 | 13477 | 13140 | 12812 | 12494 | 12185 |
70 | 11884 | 11592 | 11308 | 11032 | 10763 | 10502 | 10248 | 10000 | 9760 | 9526 |
80 | 9299 | 9078 | 8862 | 8653 | 8449 | 8250 | 8057 | 7869 | 7685 | 7507 |
90 | 7333 | 7165 | 7000 | 6839 | 6683 | 6531 | 6383 | 6238 | 6098 | 5961 |
100 | 5827 | 5697 | 5570 | 5446 | 5326 | 5208 | 5094 | 4982 | 4873 | 4767 |
110 | 4663 | 4562 | 4464 | 4368 | 4274 | 4183 | 4094 | 4006 | 3922 | 3839 |
120 | 3758 | 3679 | 3602 | 3527 | 3453 | 3382 | 3312 | 3244 | 3177 | 3112 |
130 | 3048 | 2986 | 2925 | 2866 | 2808 | 2752 | 3697 | 3643 | 2590 | 2538 |
140 | 2488 | 2439 | 2391 | 2344 | 2298 | 2253 | 2209 | 2166 | 2124 | 2083 |
150 | 2043 | 2004 | 1966 | 1928 | 1891 | 1856 | 1820 | 1786 | 1753 | 1720 |
160 | 1688 | 1656 | 1625 | 1595 | 1566 | 1567 | 1509 | 1481 | 1454 | 1427 |
170 | 1402 | 1376 | 1351 | 1327 | 1303 | 1280 | 1257 | 1235 | 1213 | 1191 |
180 | 1170 | 1150 | 1129 | 1110 | 1090 | 1071 | 1053 | 1035 | 1017 | 999 |
190 | 982 | 965 | 949 | 933 | 917 | 901 | 886 | 871 | 857 | 842 |
200 | 828 | 814 | 801 | 788 | 775 | 762 | 749 | 737 | 725 | 713 |
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| In Degrees C |
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°C | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
0 | 32648 | 31026 | 29495 | 28049 | 26682 | 25389 | 24166 | 23010 | 21915 | 20879 |
10 | 19898 | 18968 | 18088 | 17253 | 16461 | 15710 | 14998 | 14322 | 13680 | 13071 |
20 | 12492 | 11942 | 11419 | 10922 | 10450 | 10000 | 9572 | 9165 | 8778 | 8409 |
30 | 8057 | 7722 | 7403 | 7099 | 6808 | 8532 | 6268 | 6016 | 5775 | 5546 |
40 | 5327 | 5117 | 4917 | 4726 | 4543 | 4368 | 4201 | 4042 | 3889 | 3742 |
50 | 3602 | 3468 | 3340 | 3217 | 3099 | 2986 | 2878 | 2774 | 2675 | 2579 |
60 | 2488 | 2400 | 2316 | 2235 | 2157 | 2083 | 2011 | 1942 | 1876 | 1813 |
70 | 1752 | 1693 | 1637 | 1582 | 1530 | 1480 | 1432 | 1385 | 1340 | 1297 |
80 | 1256 | 1216 | 1177 | 1140 | 1105 | 1070 | 1037 | 1005 | 974 | 944 |
90 | 916 | 888 | 861 | 835 | 810 | 786 | 763 | 741 | 719 | 698 |
Manufactured under one or more of the following U.S. Patents: RE.34,534;
B1 5,341,770; 4,416,222; 4,628,184; 4,669,448; 4,672,919; 4,808,356; 4,829,983; 4,861,968; 4,904,428; 5,000,893; 5,023,031; 5,052,346; 5,081,696; 5,092,519; 5,115,767; 5,199,385; 5,277,171; 5,372,185; 5,485,879; 5,574,822; 5,596,952; 5,660,165; 5,682,666; 5,761,379; 5,943,984; 5,954,492; 5,988,117; 6,142,216; 6,684,821; 7,063,132;
Other U.S. and Foreign patent applications pending. Current Canadian Patents: 1,272,914; 1,280,043; 1,289,832; 2,045,862; 2,092,105; 2,107,012; 2,108,186; 2,112,515
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