HVAC Oil Burner Practice Test 2025 – The Complete All-in-One Guide to Exam Success!

For complete combustion in an oil burner system, it is essential to ensure there is an adequate supply of air to facilitate the chemical reaction between the fuel and oxygen. When discussing access air, the typical percentage supplied to achieve complete combustion is around 50%.

This amount of access (or excess) air serves to completely oxidize the fuel, ensuring that all the hydrocarbons are burned efficiently, thus reducing pollutants and maximizing energy output. If the amount of air supplied is too low, incomplete combustion occurs, resulting in the formation of carbon monoxide and unburned fuel, which are both hazardous and inefficient.

In many systems, having approximately 50% excess air is a common practice, balancing sufficient air supply for combustion while minimizing the energy losses associated with heating unnecessary air.