The Federal Agency on Technical Regulating and Metrology (Official source).
Measure the volume of liquid moving through the system. gost r 51649 2017 skachat pdf
To view or download the official PDF, you should use authorized technical libraries. Note that while some sites offer "skachat" (download) links, official versions are often hosted on government or accredited industry portals: The Federal Agency on Technical Regulating and Metrology
is the current Russian national standard for heat meters used in water-based heating systems. It establishes technical requirements for the accuracy, design, and testing of devices that measure thermal energy. Key Technical Specifications gost r 51649 2017 skachat pdf
The standard covers three primary subcomponents that make up a complete heat meter:
A matched pair that calculates the temperature difference between supply and return.