Determine Water Temperature Inside Tank - Bradford White ECO-DEFENDER U130T*FRN Service Manual

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 14, 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
falls.
°F 0 1
40 26109 25400
50 19906 19383
60 15314 14925
70 11884 11592
80 9299 9078
90 7333 7165
100 5827 5697
110 4663 4562
120 3758 3679
130 3048 2986
140 2488 2439
150 2043 2004
160 1688 1656
170 1402 1376
180 1170 1150
190 982 965
200 828 814
WARNING
Sensor Resistance at Various Temperatures
In Degrees F
2 3 4
24712 24045 23399
18876 18383 17905
14548 14180 13823
11308 11032 10763
8862 8653 8449
7000 6839 6683
5570 5446 5326
4464 4368 4274
3602 3527 3453
2925 2866 2808
2391 2344 2298
1966 1928 1891
1625 1595 1566
1351 1327 1303
1129 1110 1090
949 933 917
801 788 775
Page 15
SERVICE PROCEDURE ED-V
Gas Control Replacement Thermal
Well and Chamber Door Sensor
Testing and Replacement
5 6 7
22771 22163 21573
17440 16990 16553
13477 13140 12812
10502 10248 1000
8250 8057 7869
6531 6383 6238
5208 5094 4982
4183 4094 4006
3382 3312 3244
2752 2697 2643
2253 2209 2166
1856 1820 1786
1537 1509 1481
1280 1257 1235
1071 1953 1035
901 886 871
762 749 737
8 9
21000 20445
16128 15715
12494 12185
9760 9526
7685 7507
6098 5961
4873 4767
3922 3839
3177 3112
2590 2538
2124 2083
1753 1720
1454 1427
1213 1191
1017 999
857 842
725 713
15