Why does the thermometer read "HI"?

It sounds like your thermometer might have been exposed to an extreme spike in temperature and the unit itself is “hot”. Remove the batteries from your thermometer and place your thermometer in a colder dimly lit area – to cool the unit down for 30 minutes to 1 hour. This should reset the thermometer.

As general practice, please do not leave the thermometer near sources of heat such as in kitchens, near radiators, or in direct sunlight for long periods of time. Doing so will cause the thermometer to become too warm.

Before attempting to use your thermometer again, make sure the sensor has been thoroughly cleaned. Gently clean BOTH the forehead and ear probe individually with an alcohol swab – making sure that there is absolutely no buildup of dirt on either probe or probe cap. Any buildup of dirt will give a false reading. Your thermometer should be able to be used as intended.