There Is A Power Outage; You Get A System Error Message - Bryant Legacy Owner's Manual

What if . . .

There is a power outage

If you lose electricity and have batteries installed, the thermostat will
continue to display the status because it has a battery backup power
source. This means that even though your heating and cooling system
doesn't work, you will still be able to monitor your home's temperature.
In addition, you won't have to reprogram the thermostat because your
settings are retained even if the battery dies. The display will continue
to show the time for 8 hours while there is no electricity.

You get a system error message

Here are the possible system error messages and what they mean:
-- The room air sensor reports that the room air temperature is
above 150° or below -50°.
E4 This means the memory has failed and the thermostat will return
to the factory settings. Call your heating and cooling dealer.
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