The following steps will allow you to switch between Standard and Military time:

  1. Remove the front cover of the thermostat from the wall. 
  2. On the circuit board, locate the row of dip switches.  It is a horizontal rectangular black box with white switches.   Move Switch #5 to the opposite position (up or down) using an eyeglass screwdriver,  fine-point pen, or toothpick.   It is the 5th switch from the left. 
  3. UP = 24   Hour, DOWN = 12  Hour
  4. Locate the Hardware Reset button on the circuit board labeled HW RST and press it for 3 seconds. 
  5. You will see 88:88 flashing in the display reminding you that the day and time need to be reset.  Move the SET slide switch to “Day/Time” and fix the day and time.    Return the SET slide switch back to RUN.   
  6. Finally, put the front half of the thermostat back onto the wall.