The FG-100B and FG-101B solder tester/ Tip thermometer were designed so the user can change between Celsius and Fahrenheit on the display Unlike their Predecessors the FG-100 and FG-101  which were purchased and received set to either Celsius or Fahrenheit temperature scales .

To toggle the Display between Celsius and Fahrenheit displays on your FG-100B / FG-101B Tip Thermometer follow this process

First turn the unit off , Next Press and hold the AUTO/SEND key on the right side of the unit while simultaneously pressing the ON/OFF key 

The display should now switch between Celsius and Fahrenheit you can verify this change by looking in the top right corner of your display where a °C or °F is displayed  .

For more information on the FG-100B or FG-101B Please view our Technical documents / users Manual found on our website .