If you are reading 12% CO2, what does it indicate?

A reading of 12% CO2 indicates incomplete combustion in a high-pressure boiler system. In a perfectly efficient combustion process known as complete combustion, CO2 levels would be higher, usually in the range of 13-15% or more, assuming air is not limiting. The presence of lower CO2 levels, such as 12%, suggests that there is still unburned fuel in the combustion process, indicating that not all fuel is converting to carbon dioxide.

Incomplete combustion typically results in higher levels of carbon monoxide and other pollutants, which can have environmental and safety consequences. It indicates that the fuel-air mixture is not optimal, leading to efficiency issues and potential operational hazards within the boiler. Understanding these implications is crucial for maintaining effective and safe boiler operations.