Gas-burning forced-air furnaces are very common heating systems. How does a gas furnace work? That’s an important question to ask. Knowing how gas furnaces work is a great step, whether you’re working on understanding a system you own or one you need to purchase in the future. Here’s how a gas furnace operates!
How Gas Furnaces Work: The Basics
A furnace is a heating device used to transfer heat uniformly through a home or building. It burns fuel to heat air or water. It distributes warmth throughout a building to keep it comfortable in the cold season.
We refer to a majority of furnaces as forced-air furnaces because they use a blower to direct hot air. Some furnaces produce warmth by burning things like oil, coal, or wood. However, natural gas or propane are both more common sources of fuel for furnaces.
The Heating Process
First, it’s essential to understand the heating cycle. That is the series of steps your gas furnace goes through to warm your home. The furnace is connected to the gas supply through a pipe that enters your house from the outside. While natural gas models have underground linkages to a natural gas pipe network, propane units require an external storage tank.
- The burner ignites the gas once it reaches your furnace from a tank or gas supply network.
- Your home’s cooler air enters the furnace. There, it is warmed in the heat exchanger by the gas as it burns.
- Then, the furnace’s vent is used to funnel combustion exhaust outside of the house through an exhaust pipe. This ventilation is crucial to keeping your home safe.
- After that, the blower fan distributes the heated air throughout your home. This will be according to where the thermostats sense a requirement for heat.
- As the warm air is dispersed, the temperature progressively rises. Return ducts are used to send cold air back to the furnace.
- Finally, the thermostat turns off the gas valve after it detects the desired temperature.
Furnace Parts
The circuit board is a tiny control board that deciphers numerous signals coming from the furnace. When the thermostat requests heat, it responds by sending signals that trigger events like the gas valve opening and the burners turning on.
The blower fan is a small electric fan and motor that circulates heated air throughout the house depending on the demand for heat.
The burners are small openings in the furnace through which gas escapes and ignites to form steady flames.
The igniter is the mechanism that ignites the gas that the burners release. Igniters produce a spark or hot surface that ignites the gas as it passes through. This starts the process of ignition.
The heat exchanger is the group of metal tubes that separate the air blowing into the home from the combustion process. The heat exchanger warms cold air and redirects it into the house.
The flame detector halts the flow of gas if it detects no heat. This prevents gas from dangerously piling up in case the igniter fails.
The plenums. The two types of plenums are return-air and supply-air. A return-air plenum transports air from the rooms to the furnace for heat. A supply-air plenum brings heated air to the ducts to warm the home.
The transformer provides electricity to the furnace and lowers the voltage as needed.
The gas valve controls the gas pressure coming into the furnace from a propane tank or a natural gas supply.
The filter is the barrier which traps dirt and debris.
The thermostat is what monitors and manages indoor temperature, controlling the heating cycle of the furnace based on where you set it. Thermostats are positioned at other locations throughout your home but connected to the heating system.
How Does a Gas Furnace Work For The Long Haul?
Gas furnaces last 15 to 20 years on average. To keep your furnace running for as long as it can, you’ll want to maintain it well. It’s also important to consider the safety tips of using gas furnaces so you can stay safe and cozy every winter.
Gas Furnace Safety Tips
- If you smell gas in your house or coming from a gas device, do not start it. Immediately leave your home and make a call to the nearby fire station or gas company.
- Maintain a 3-foot minimum distance between anything that can burn (such as paper, paint, wood and fabric) and any heat appliance.
- At all times, keep kids at least 3 feet away from open flames and heaters.
- Install and test smoke and carbon monoxide detectors on a regular basis.
- Before you leave the room or go to bed, turn off portable heaters.
- Have your appliances installed and maintained by a licensed, experienced specialist. Installation must follow both code requirements and manufacturer guidelines.
- Always hire a pro every year for maintenance.
Gas Furnace Maintenance
It’s important to take good care of your gas furnace to ensure it lives its full lifespan. Proper maintenance of your heating appliances saves you time and money. Here are some basic maintenance tips:
- To ensure that the heater runs effectively throughout the winter, keep it clean. Regularly change the filter and clean the vents and registers.
- In order to prevent airflow obstruction, make sure the vents and surrounding area are clear. Check indoors and outdoors for any obstacles that might be blocking your unit. Clearing the immediate area keeps your unit running efficiently and decreases risk of a fire.
- Don’t skip your annual maintenance check from your local HVAC professional. They can help your unit run its best and spot problems before they become a stressor for you.
Don’t Wait to See a Pro! Live Free Gas Furnace in NH
In order to be prepared for the winter chill and avoid having to wait around for busy contractors, we always advise having your gas furnace in NH serviced or installed in the fall. By making early plans, you may prevent issues from arising and ensure the safety of your family as well as yourself.
Schedule your gas furnace maintenance service with Live Free Heating Cooling Electric of New Hampshire or call us at (603) 270-9182 for a quote on a new installation!