What If; The Battery Icon Is Displayed; Aux Heat On" Is Displayed (Heat Pump Systems Only); Em Heat" Is Displayed (Heat Pump Systems Only) - Carrier Touch-n-go TC-PAC Owner's Manual

WHAT IF...
The battery icon is displayed
The battery icon appears on the display only when the battery starts to lose power.
Replace it when one-third of the icon is black.
If you wait until the icon is just a silhouette with no black bars, the thermostat won't
have the power to function correctly. Replace the battery to restore thermostat
functions.
"Aux heat on" is displayed (heat pump systems only)
Aux heat on is auxiliary heat. It applies only to the heat pump version. If it is on,
you will see aux heat on. When it is displayed, it means the system has determined
that it's too cold outside for your heat pump to heat the house without help, so it's
getting help from the electric heaters. This happens automatically.
"Em heat" is displayed (heat pump systems only)
Em heat is the display term for emergency heat and applies only to the heat pump
version. When emergency heat has been turned on, Em heat is displayed when you
press the mode button. You have to turn on emergency heat manually - it doesn't
happen automatically - so if you see Em heat on the display, it means somebody
has turned it on.