Health-O-Meter scales must be reset when moved to another location, according to the Health-O-Meter FAQ. This process is also known as calibrating the scale and is listed in the Health-O-Meter scale instruction manual. Performing the action allows the scale to display the correct weight. You may also need to do this if the scale's display shows the letter "E." Doing the reset involves no tools and nothing complicated at all.
Place the Health-O-Meter scale on a flat surface. Make sure the scale is indeed level.
Tap the lower left or right corner of the scale three times. After you do this, you'll notice the display shows "---."
Wait a few seconds for the scale to reset and recalibrate. When it's ready for use, it will display "LB" or "KG," depending on your display selection.