Hello, What is the accuracy of a heat meter following the "Metrological class 2 in compliance with the European Measuring Instruments Directive 2014/32/EU"? And the corresponding water measurement accuracy? I use for some measurements a heat meter (ultrasonic flow sensor zelsius® C5-IUF Zenner 2,5) and I am looking for the corresponding uncertainty of the measurement. Not easy to be found in the technical document of the heatmeter. Thank you.