| A furnace is a device designed to heat a home or | | | | rooms in your house at the start. After either the |
| other building. A gas furnace is one that burns | | | | preset time (roughly two minutes) or |
| gaseous fuel such as natural gas or propane.If | | | | pre-established temperature is reached, the |
| your home has a gas furnace, you may be | | | | blower's motor is turned on and it blows air over |
| curious about how it actually works. Understanding | | | | the heat exchanger. At the heat exchanger, the |
| its parts and how they work together can help | | | | air is heated and then blown through the duct |
| you ensure that your unit is operating efficiently, | | | | system into the various rooms via vents in the |
| and may even help you perform small repairs | | | | floor, walls or ceiling. |
| yourself rather than spending big bucks on calling | | | | The Heat Goes Off |
| in the pros. | | | | You may have noticed that just as the heat in |
| The Heating Cycle Begins | | | | your home turns on when a certain temperature |
| The process starts with the thermostat that is | | | | is reached, it also turns off after the rooms are |
| inside your home. The thermostat senses the | | | | warm enough. This is also because of the way |
| temperature inside the room. When the | | | | the thermostat works with your gas furnace. |
| thermostat senses that the temperature dips | | | | Basically, the thermostat again senses the |
| below the point at which you have it set, it kicks | | | | temperature in the room. When the room warms |
| the system into gear. On more modern units, this | | | | up to the temperature set by you at the |
| means that an inducer fan then pulls air through | | | | thermostat, the gas valve is switched off, |
| the unit until adequate combustion airflow is | | | | stopping the flow of gas. After the gas is turned |
| established. After an appropriate level of airflow | | | | off, the blower motor will still run for a few |
| has been reached, the gas valve opens and allows | | | | minutes. The reason for this is to allow the heat |
| gas to pass through. The gas then flows through | | | | exchanger to cool off a bit. How long the blower |
| the burners and is lit up by either a spark or the | | | | motor runs after the gas supply is shut off |
| heat from an ignitor. If the unit in your home is an | | | | depends on either a timer or a temperature |
| older one, the unit is likely to have a small flame | | | | switch. |
| that burns continuously, otherwise known as a | | | | Basic Maintenance |
| standing pilot, to light the gas. | | | | Whether you have a gas furnace or an oil |
| Your Home Gets Heat | | | | furnace, some routine maintenance will be |
| After the furnace senses that the thermostat | | | | necessary in order keep everything running |
| has triggered the flame and that it is properly lit, | | | | smoothly and to extend the life of your unit. Now |
| the actual spark (or ignitor) is turned off. If your | | | | that you understand the basics of how a gas |
| unit is older and contains a standing pilot, it will not | | | | furnace works, you can probably handle routine |
| be turned off. At this point, the gas will typically | | | | maintenance yourself, with a little more research |
| burn for at least two minutes before the blower | | | | and some online tutorials. If you feel more |
| starts to disperse heat throughout your home. | | | | comfortable trusting the experts, you can invest |
| The reason for this is to give the air an adequate | | | | in a maintenance contract, and for as little as |
| period of time to warm up and so that cold air | | | | $100 a year, a dealer will take care of it for you. |
| won't be pushed through the vents into the | | | | |