If a valve’s tight shut-off is impaired, the seat leakage does not become visible on the outside. Yet, it can be a problem on the inside. If the seat and plug do not shut off properly, impermissible amounts of the medium continue to flow through the valve even though it is supposed to be fully closed. The medium always finds a way between the seat and plug. An immediate consequence is that the control accuracy deteriorates. In the long run, the valve’s service life is shortened. By connecting a sensor to the Series 3730 Positioners with integrated diagnostics, SAMSON has found a way to reliably detect and indicate leakage inside the valve.