Carbon monoxide is a gas well known for its toxicity and difficulty to detect. The last thing you would want is to be exposing your family to this gas through the use of appliances such as gas dryers.
Through explanations of the processes that occur in gas dryers to produce heat, to tips in detecting carbon monoxide, this article is a must-read to put your mind at ease and keep your family safe.
Gas dryers are capable of producing carbon monoxide but this is an indication that the dryer is not working properly. A correctly functioning dryer produces carbon dioxide, water, and heat (complete combustion). A dryer that does not have enough combustion air produces carbon monoxide, water, and less heat.
Gas Dryer Combustion Produces Carbon Dioxide
Combustion is a chemical reaction that occurs when a hydrocarbon fuel is combined with oxygen (oxidized) to release heat and light energy.
In more common terms, combustion is the burning of fuels such as natural gas and liquid propane.
These fuels are hydrocarbons, which means they contain hydrogen and carbon.
When there is lots of oxygen available, complete combustion occurs, such that the carbon part of the fuel is oxidized to produce carbon dioxide.
The hydrogen in hydrocarbons is also combined with oxygen to form water.
Combustion is known as an exothermic reaction. “Exo” means outside or external, and “thermic” means heat. So, combustion is a reaction that produces heat.
Combustion can be either complete or incomplete. The reactants are the same, but the products differ.
Complete combustion, which is the reaction we are after, requires that there is sufficient combustion air (and hence plentiful oxygen).
If gas dryers are installed and operated correctly, there will be sufficient oxygen, and complete combustion should occur, so that heat, carbon dioxide, and water are produced.
Insufficient Oxygen Produces Carbon Monoxide
When there is not enough oxygen, incomplete combustion takes place.
Incomplete combustion occurs when there is partial oxidation of a fuel, such that there is not enough oxygen to form carbon dioxide, which contains one carbon and two oxygen atoms.
Instead, carbon monoxide is formed, which contains one carbon and one oxygen atom.
Less heat is produced from this process, and as many of us will know, carbon monoxide is colorless, odorless, and tasteless, but very poisonous.
In addition to carbon monoxide, the leftover carbon forms soot during incomplete combustion, and water may also be formed depending on the type of fuel used.
Hence, if your gas dryer is not installed or operating correctly, and/or if there is not sufficient combustion air, there is a risk that it will produce carbon monoxide.
The fact that carbon dioxide and carbon monoxide are produced makes it essential that gas dryers be vented properly.
Combustion Air Supply
By supplying combustion air for your dryer (different to makeup air), you can prevent incomplete combustion from occurring.
This is because you are ensuring that there is plentiful oxygen available to combine with the fuel.
Combustion air can be supplied to the room containing your gas dryer through direct or ducted vents leading through crawlspaces, exterior walls, or the roof. This depends on where your dryer is located.
Combustion air can be provided to the room in which the dryer is installed. Alternatively, combustion air can be supplied through ducts fixed to the air inlet on the dryer.
How to Tell if Dryer Is Producing Carbon Monoxide
Since carbon monoxide is colorless, tasteless, and odorless, it may be considered a “silent killer” because it is difficult to detect.
The most reliable way to tell if your gas dryer is producing carbon monoxide is to fit a carbon monoxide detector (amazon link).
However, since carbon monoxide is a product of incomplete combustion, other signs of incomplete combustion could signal the presence of this dangerous gas.
Soot is often also produced as a byproduct of incomplete combustion, so the buildup of yellow stains or black, sooty marks on or around your gas dryer could indicate that incomplete combustion, and hence carbon monoxide production, is occurring.
If you can see the pilot light of your gas dryer (only older models still have a pilot light), you may also notice that a yellow flame is produced or that it blows out frequently if incomplete combustion and production of carbon monoxide is occurring.
Finally, since incomplete combustion is less efficient, you may notice that your dryer is not working as well because it is not producing as much heat.
Ensuring that your gas dryer is serviced regularly will also help to ensure that it functions properly.