Once the pressure differential between the upper end of the piston (pressure in the heat exchanger) and the intermediate chamber (pressure controlled by the control unit) is created, the SSV shuts off, increasing the pressure of the valve spring. The valve plate is tightly pushed down on the sitting valve and creates a pressure-resistant barrier that cuts off the connection. In the remote signal form, the valve plate closure is electrically decided. If the pressure in the heat exchanger (above the valve plate) fell below the reaction pressure of the control unit (SSV response pressure minus0,3 to 1 bar), the shut-off protection system (SSV) would be re-opened. Depending on the temperature of the hot water line, the remote indication system is available in two different designs. It can’t be changed anymore.