A single installation includes multiple components, greatly reducing the number of necessary tank penetrations resulting in lower overall costs. General description of filling control: The 2/2-way cartridge valve automatically stops filling at maximum level. This is provided by the highest level contact at Lx. At power-up of the unit the valve position will change to “b”. This means the flow path from 2 to 1 is open and filling is in process. When the fluid level reaches the highest level contact (normally open contact at position Lx), the valve will switch to position “a”. The path from 2 to 1 is closed now. The valve blocks the flow from the filling port to the reservoir. During operation a second level contact signals a lack of oil. Using an external control a refill of the tank can be made automatically via the filling terminal or the maintenance personnel can be called to do this. In both cases the filling valve will be reset to position “a” as soon as level Lx is reached.