If your repair technician just gave you the bad news that your furnace has a cracked heat exchanger, and you said, " A cracked what?" you're in the right place. This article is going to go over what a heat exchanger is, why it cracks and what you can do about it if you have a home warranty. To really understand why a damaged heat exchanger is so problematic, and how your home warranty company can help, we have to go over the basics of how a furnace works.
How does a Furnace Work?
Looking at a furnace quite simply, it has four main parts that allow it to heat your house:
Draft Motor
The first is the draft motor. The draft motor kicks on when there's a drop in temperature in your house, and your thermostat tells your furnace that warm air is needed. When this happens, your draft motor begins to pull ambient air into the unit from the surrounding area.
Burners
As air is taken into the furnace to be warmed, gas is turned on in the burners of the furnace. The furnace ignites this gas with a spark, and the burners create a flame. This flame produces hot gasses that go into the heat exchangers.
Heat Exchangers
Heat exchangers are a series of metal tubes that heat up and stay extremely hot. They hold the hot gasses and carbon monoxide the burners produce. These gasses are poisonous, so the heat exchangers are attached to a flue that vents the gasses outside.
Blower
As the draft motor brings air into the furnace, the blower motor begins to force air past the extremely hot metal tubes of the heat exchangers. Obviously, the hot gasses from the burners that are inside of the heat exchangers don't mix with this air, unless they have a crack. As long as the heat exchangers have an air-tight seal, the air is simply blown over them. This warms the air up, and the blower continues to push the air throughout your ductwork, providing warm air through your house.
If your heat exchanger is cracked, however, this could prove problematic for homeowners. There is a possibility that those poisonous gasses from your burners could leak into the air being blown throughout your home.
Why Does your Heat Exchanger Crack?
However, if your furnace technician has found a crack in your heat exchanger, and your furnace is still relatively new, there could be some improper maintenance causes:
Limited Air Flow
If your furnace filter is dirty and hasn't been changed, or the furnace can't bring air into the unit because of furniture blocking return vents, your heat exchangers could crack. Without sufficient airflow, the burners and heat exchangers have to heat up to higher temperatures to combat the limited air supply, which could cause damage.
Combustion
If the burners on your furnace aren't combusting the gas properly, they could burn hotter, heating up the metal of the heat exchanger to higher temperatures, causing cracks.
Rust
Sometimes condensation occurs with gas furnaces. If this condensation isn't cleaned out or disposed of properly, the heat exchangers could rust.
Why is a Cracked Heat Exchanger Bad News?
Although not every crack in a heat exchanger means you will be sick with carbon monoxide poisoning, the crack has the potential to get bigger and cause sickness or death. There's no simple way to fix the cracks either. The American Gas Association has said that if a heat exchanger is cracked, it must be replaced.
Will my Home Warranty Cover the Replacement?
If you have a Landmark home warranty and you get the bad news that your furnace has a cracked heat exchanger, your first question will most likely be: "Will my home warranty cover this?"
The answer is yes! As long as the crack has developed within the time of your contract, and was due to normal wear and tear, Landmark Home Warranty will cover the repair or replacement for a small service call fee.
You can ensure that your heat exchanger is covered by a home warranty by doing a few things:
1. Proper Maintenance
Make sure to change your furnace filter every one to three months, and complete other maintenance that your furnace manufacturer recommends. This will ensure your heat exchangers only crack from wear and tear, and will be covered by your home warranty.
2. Hire a HVAC Technician for an Inspection
Although not required to purchase a home warranty, home inspections are always a good idea. Home warranty companies generally determine how long a heat exchanger crack has been developing by its size, as well as the home inspection. If the inspector looks at the heat exchangers with a mirror, and checks it with a CO2 detector to ensure no carbon monoxide is present, he or she should note that on the inspection report. The home warranty company will be able to see there was no crack at the beginning of the home warranty contract.
For more information on what a home warranty covers when it comes to furnaces, go to our coverage details page. You can learn more about home warranties by browsing our home page as well.