When a direct oil heater is switched on the air compressor draws in air, pressurises it and passes it through an air line to the burner head nozzle. The air flow causes fuel to be drawn from the tank. The fuel and air mix is then sprayed into the combustion chamber. The mixture is automatically ignited by the spark plug and a high temperature heat stream is generated in the combustion chamber.
Air is drawn into the unit by a fan and is pushed around the cool chamber situated between the combustion chamber and outer casting. This fast flowing air sucks the heat stream out of the combustion chamber, providing the required heat. The heat output is giverned by the compressor - the higher the air pressure, the hotter the flame.