Been a few months now since we talked about furnaces. This next one is still an 80% Gas furnace but it is a forced draft. It uses an Induced Draft Motor (IDM) to propel the burning gases up the metal flue pipe and also will use either a spark ignition or hot surface ignition system to ignite the gas instead of a standing pilot. These systems are more efficient than the standing pilot systems and are now going to be around a little bit longer due to the postponement of the 90% system change over deadline which was 1 May 2013. They also have more safety features such as a roll-out switch, flame sensor, as well as a newer limit switch. These units have a circuit board to control functions from the thermostat to the outside unit during the heating and cooling season. This furnace can be expensive to repair so maintain these systems yearly. See below a more detailed picture.