The most common carbon monoxide (CO) problems involve a lack of oxygen – either because there is simply not enough, or because the flames cool off before the carbon can join with it. CO is produced whenever a fuel is burned without enough oxygen on hand. Carbon atoms in the fuel that normally join up with two oxygen atoms to form carbon dioxide, which is harmless to human health, end up with only one oxygen atom and instead form CO.
Basic Steps to Getting CO Into Your Life
It is not enough to understand how to create CO, we need to examine all of the coordinating factors which can create it and allow it into the living space.
Five basic factors not only lead to the production of CO, but will aid in getting it into your homes. Any one major failure can get CO into your home, but typically three of these factors must go awry to produce a major problem.
The Flow of Fuel
As you add fuel to a fire, the fire produces more Btus of heat. It also requires more oxygen to combine with the carbon and hydrogen to form carbon dioxide and water vapor (H2O. As you continue to add fuel, the amount of available oxygen needs to keep up or CO will be produced, which is incompletely burned carbon. In engineered systems (all modern combustion appliances) the amount of air that can move through the unit is limited by the design. Any additional restriction (dirt, lint, carbon) will result in the air flow being reduced. The air flow is controlled by the laws of nature (hot air rises). The flow of fuel is controlled by the pressure applied to the fuel and the size of the hole it is forced through. Any problem with the pressure of fuel input can lead to problems with the fuel/air mixture.
Competition for Air
We refer to many kinds of air when describing a standard combustion appliance (combustion air, primary air, secondary air, dilution air, return air, supply air, and so on). Air, or more precisely the oxygen in the air, is fundamental to the combustion process. The amount of air than can come into standard appliances is typically controlled by two basic systems. First is the mix of gas and air before combustion (primary air). This is controlled by the design of the burner, the pressure of the gas, and any control of the air stream. The secondary air, or additional air that is needed to supply oxygen to the flames, is simply controlled by the amount of air that is drawn through the heat exchanger.
In order for these two simple systems at the appliance to supply adequate oxygen for complete combustion, there needs to be sufficient air to the area around the appliance. Any competition for the air needed for the combustion process can lead to problems. The power of the competition does not need to be strong to overcome the natural forces of the combustion appliance.