What two things are made easier by pre-heating the oil?

Pre-heating the oil is critical in oil burners due to the impact it has on circulation and atomization. When oil is heated before it enters the burner, it becomes less viscous. This reduction in viscosity enhances the circulation of the oil throughout the fuel system, allowing for a more efficient flow to the burner.

Additionally, pre-heated oil is more readily atomized when it reaches the combustion area. Atomization refers to the process where the liquid oil is broken into fine droplets, which is essential for efficient combustion. Proper atomization ensures that the oil mixes effectively with air, facilitating a more complete and efficient burn. This dual enhancement of circulation and atomization leads to improved performance of the oil burner, resulting in better fuel efficiency and reduced emissions.

The other options touch on related concepts, but they do not capture the specific benefits of pre-heating with the same clarity as circulation and atomization.