The essence of diagnostics is to fill one side of the equipment with a forming gas containing a safe concentration of hydrogen. On the other hand, measure the hydrogen concentration with a high-sensitivity gas analyzer (instrument sensitivity 0.5ppm). The small size and agility of the hydrogen molecules and the high sensitivity of the instrument ensure that incipient hairline cracking or pitting corrosion can be detected that cannot be detected by other methods (eg water pressure test, penetration test, etc.) at that stage. The advantage of this method is that the wear and tear of the equipment (plates) is noticed before the larger molecules (eg milk, beer, wine, etc., components and water) can pass to the other side. Regular, e.g. with annual diagnostics, the condition of the equipment can be monitored.