Used oil is pumped from your tank to the heaters burner where it is preheated.

Low pressure air enters the heater’s burner and is preheated.

In the burner, preheated used oil & air are mixed causing a mist of oil to pass though the nozzle where it is ignited. This is referred to as atomization.

The heater is thermostatically controlled to keep a continuous / steady flow of heat without the need for manual adjustments to get ‘comfortable’.