Checking Temperature Sensors - Lochinvar ArmorX2 1.3 Service Manual

3
Troubleshooting

Checking temperature sensors

The water heater temperature sensors (inlet water, outlet water, system water, and flue) are all resistance type devices. The
following tables show the correct values for the sensors at various temperatures. Use an ohmmeter to read the resistance of the
sensor at a known temperature. If the resistance of the sensor does not closely match its corresponding table, replace the sensor.
Table 3B - Inlet/Outlet and Tank Sensor Resistance vs. Temperature
Temperature
50
68
86
104
122
140
Table 3C - Flue Temperature Sensor Resistance vs. Temperature
Temperature
68
86
104
122
140
158
40
Resistance
18,780
12,263
8,194
5,592
3,893
2,760
Resistance
14,773
9,804
6,652
4,607
3,252
2,337
Service Manual
Temperature
158
176
194
212
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--
Temperature
176
194
212
230
248
--
Resistance
1,990
1,458
1,084
817
--
--
Resistance
1,707
1,266
952
726
560
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