Simply explained, a furnace begins with the thermostat. Whatever desired temperature you set for your home, the thermostat will then detect when that temperature has dropped. From there, the thermostat signals the furnace to activate. The furnace will run until the temperature has reached the set comfort level.
There are different variants of furnaces, however, most homeowners commonly use either electricity or natural gas to warm the air.
For a gas furnace, when a thermostat triggers the furnace to turn on, a valve will open and supply fuel to the pilot light. The pilot light ignites, lighting the burners in the combustion chamber. This heats up the heat exchanger.
Perhaps the most critical part of your furnace, the heat exchanger gets hotter and hotter. Once the air is heated up sufficiently, the air is moved into the plenum and exits through the supply ducts. From there, the air heats the home to the set temperature.
Working parts of the gas furnace include the burner, heat exchanger, ductwork, ventilation pipes or flue, return ducts, air filter, blower motor, supply plenum, and hot surface ignitor.
For an electric furnace, the air is drawn into the furnace system and through a heat exchanger. From there, heating elements heat the air; the blower pushes the air into your homes ductwork. The ductwork will then distribute air evenly throughout the areas of your home.
Working parts of the electric furnace include electric heating elements, air filter control, cold air return, air filter, blower, belt, motor, and ductwork