Heating device for the temperature conditioning of preforms, and method for operating a heating device of this kind

A method for operating a heating device for thermal conditioning preforms made of a thermoplastic material in which each respective one of the preforms is prepared for a subsequent forming process during which the preforms are formed into containers with a forming fluid fed under pressure into the preforms. The heating device is operated in at least a first operating state and a second operating state. The second operating state is a startup phase of the heating device during which a temperature of the heating device approaches an equilibrium temperature of a thermodynamically stable equilibrium state of the heating device. The first operating state is a continuous operation state following the startup phase. The second operating state is operated with a heating output value that varies over time. Furthermore, the invention relates to a heating device and a machine having a heating device, which are configured to implement the method.