Reflow systems as well as the preheating zone of wave soldering systems consist of a number of preheating zones, one following after the other in the direction of board travel. As a rule, each of these zones is adjusted to a specific temperature setting, which gives rise to a board-specific temperature/ time process, displayed as a profile. The heating process is therefore fully controlled and reproducible. A heating module consists as a minimum of an emitter (heater), a thermo couple / temperature sensor for the temperature control and a housing. Convection heating modules have in addition a blower installed with which the air is being moved.