PDX Series
PDX SERVICE PROCEDURE VI
Gas Control/Thermal Well Testing and
Replacement
WARNING
Stored water may be HOT when performing the following steps in this procedure.
Take necessary precaution to prevent personal injury.
Determine Water Temperature Inside Tank
Note: It is important to understand once the resistance for the thermal well is determined from page 25, water flow through the heater should not occur. Prior to performing the steps below, turn off the cold water supply to the water heater. This will prevent cold water flow into the tank affecting the resistance value of thermal well.
Step 1. Position gas control power switch to “OFF” position.
Step 2. Draw approximately 4 gallons of water from drain valve into a container and discard. Draw an additional gallon and immediately measure water temperature using an accurate thermometer. It may be necessary to open a hot water faucet to allow heater to drain.
Step 3. Using the chart below, determine correct resistance value for the water temperature from step 2.
Example: | If temperature of water is 84°F, then the resistance through the sensor would be | |||||||||
| 8449 (see shaded area). NOTE: Sensor resistance increases as the temperature | |||||||||
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| Sensor Resistance at Various Temperatures |
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| In Degrees F |
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°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 | 1000 | 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 | 2697 | 2643 | 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 | 1537 | 1509 | 1481 | 1454 | 1427 |
170 | 1402 | 1376 | 1351 | 1327 | 1303 | 1280 | 1257 | 1235 | 1213 | 1191 |
180 | 1170 | 1150 | 1129 | 1110 | 1090 | 1071 | 1953 | 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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