Thermostat verification

Furnace thermostat are made to operate with 24 V and with battery backup. First thing what you can do if you are not sure the thermostat send the signal to the furnace is to replace the battery. If the thermostat show heat on , or cool,  check the LED on the bottom furnace door and see if is flashing slowly or give an error code (number of flashing). For an error code, means the signal was sent but furnace not working properly.