The TDS salinity control system is used to limit the level of salts and minerals dissolved in the water of the steam generator within the permissible value by the manufacturer, avoiding the risk of entrainment due to unacceptably high levels of salinity and thus reducing the possibility of damage to the boiler body or the included accessories.

The system works by opening the exhaust valve at regular intervals so that amount of water reaches the conductivity probe located in the measurement chamber. The probe measures the electrical conductivity of boiler water whose value is related to concentration of dissolved salts. If the value results to be less than the setpoint set by the regulator, at the end of the time the exhaust valve closing. If it is higher, the system continues to repeat the discharge cycle until the measured value returns within limits.