Ueber die Lebensdauer von Waermezaehlern oder. Sind Waermezaehler ihren Preis wert?

In Germany service life of heat meters is in most cases five years. So service life equals the period of validity of calibration. After this time many meters, especially small and medium-sized flow sensors are sent to be scrapped, because repair costs seem to be too high and producers like to offer new meters in such cases at considerable price reduction rates. But for commercial reasons in the district heating enterprises and in order to conserve energy and material resources it is necessary to leave this throw-away meter concept. At the moment the sub-assemblies of heat meters have different measurement consistency and service lives. Therefore it would be for consideration whether the fixed calibration period needs either to be reviewed or made dynamic. From next year in Germany a sample test method for installed meters will be introduced to find out meter lots with longer measurement durability in order to leave them additional three years in the networks. Furthermore meter types have to be developed, which have considerably longer durability and/or can cheaply be repaired after the end of a calibration period. According to these demands the methods for testing the measurement durability as a subject of pattern approval tests should be overworked with regard to longer testing times. That is one result of the AGFW Test Programme on flow sensors.