Important for us is the second principle of combustion management, which is to not use too much oxygen.

The correct amount of oxygen requires three types of measurement: first, active control of air and fuel flow; second, offgas oxygen measurement; and third, measurement of offgas combustibles. For each heating process, there exists an optimum condition of minimal offgas heat loss with acceptable levels of combustibles concentration.

Minimizing excess oxygen pays an additional benefit: for a given offgas temperature, the NOx and SOx level is lowest when excess oxygen is kept lowest.