56
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 upper sensor or lower sensor assembly, compare the resistance of the sensor terminals (blue leads for
upper sensor, yellow and black lead for lower sensor) 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. 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.
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
In Degrees °C
°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
Summary of Contents for POWERED DIRECT VENT SERIES GAS-FIRED COMMERCIAL WATER HEATER
Page 17: ...17 Figure 6 Figure 7A Figure 7B...
Page 60: ...60 SECTION XIV NOTES...
