diagnose a hot glue system it is necessary that the control unit 170 have information on the operating time and on the exceeding of limiting parameters of the melter 100 the connected heatable feed hoses 200 and the heatable application valves 300 in this regard it is advantageous if this information is stored in the hoses and application valves themselves so that after a repair and during connection of the components that were already in use the previously attained operating time and the exceeding of established limiting parameters are automatically reported to the control unit 170 during operation the control unit cyclically updates the elapsed time indicators contained in the components and the data memories for the limiting parameters the operating time and the attained limiting parameters of the components can thus either be interrogated by the control unit 170 if the components are connected to the melter 100 or after detachment from the melter 100 externally interrogated if the component for example is being subjected to repair for this purpose the data storage medium can for example be machine writable to monitor the hot glue system it is advantageous if the control unit 170 can exchange data with the higher order control unit of the production system or with an external monitoring and diagnostic unit so that the information that is acquired.