Should a furnace thermostat have a constant 24 volts?

Yes, a furnace thermostat typically requires a constant 24 volts for proper operation. This low voltage is supplied by a transformer connected to the heating system and is necessary for powering the thermostat and controlling the heating equipment. If the thermostat does not receive a steady 24 volts, it may malfunction, leading to heating issues. Regular checks of the power supply can help ensure the system functions correctly.