The heart of the oil burner is the modulating MDP oil pump. It meters the fuel mass flow linearly and continuously within a modulation range of 3: 1. The dosing function is not in the nozzle, but in the pump, which delivers a defined volume per stroke and thus doses volumetrically according to the variable stroke length. The MDP is designed in such a way that no air bubbles can reach the nozzle. This is a decisive advantage, especially with blue burners in the low load range, because the flame is protected from interruptions in the oil supply in this way.