How to Troubleshoot a Digital House Thermostat

Check the system switch for the correct temperature setting. To produce heat, raise the temperature to a degree value higher than the actual room temperature shown on many digital thermostat display screens. To cool the home, lower the temperature to a setting below the current room temperature. Whether heating or cooling the home, give the system a minimum of five minutes to make the temperature adjustment.

Replace the batteries in the thermostat unit if the display does not light up. Most manufacturers use common household battery sizes, such as AAA and AA. Look in the owner's manual to see if another battery size is necessary for your thermostat, such as button batteries. Make sure the ends of the battery are aligned with the respective positive (+) and negative (-) connections in the battery slot. You may have to perform a hard reset on the thermostat by pressing the "Reset" or similarly labeled function.

Confirm that electrical power is running to the heating and cooling system. At your home's circuit breaker or fuse box, switch the breaker back to "On" or replace a blown fuse. Though the thermostat's digital display might be powered by battery, the home's heating, ventilation and air conditioning system runs off electrical power.

Verify that the time is properly configured on a programmable digital thermostat if it is not heating or cooling as desired. Make sure that the clock is set to use "A.M." during the day and "P.M." during the evening. Also, ensure the programmable thermostat is not in a type of override mode or similar state. Having the ability to manually adjust the temperature will prevent the thermostat from automatically carrying out programmed settings.