Smith Cast Iron Boilers GT Series - Manual (Page 40)

GT INSTALLATION AND OPERATION INSTRUCTIONS Page 40
The following are the thermister curves for diagnosing
the water and outdoor air sensors.
1. Measure the resistance of the thermister when
disconnected.
2. Using the appropriate chart, fi nd the resistance and
move vertically for the water probe or horizontally for
the air probe until the line is intersected.
3. Move 90 degrees to the corresponding temperature.
4. If the temperature is plus or minus 10°F, - 12 °C,
then the probe is operating correctly.