DIAGNOSIS Incorrect temperature reading due to internal heat from the wall or the unit's own electronics. This is called 'heat poisoning'.
FIX The thermostat must be mounted on an interior wall, away from direct sunlight, drafts, doorways, and heat sources like lamps or electronics. Ensure there are no wires or pipes in the wall behind it generating heat. Relocate the thermostat if necessary.
IF THAT DIDN'T WORK Check the temperature calibration offset. Go to Settings > Installation > Temperature Offset. You can adjust the reading by +/- 3 degrees Fahrenheit to compensate for a persistent error.
HEADS UP Do not install the thermostat over an unused fireplace or on a wall with poor insulation. The internal sensor is sensitive to radiant heat from the wall itself. An improperly located thermostat will never control properly.