Timed automatic draining units that check concentration are the ideal systems for checking salinity and cooling systems; draining is regulated with a pause/operate timer or by continually checking conductivity in the circuit. Convenient operation and select materials ensure complete reliability over time with very low maintenance requirements. Motorised valves with spring closure ensure draining is interrupted, even in special conditions such as power cuts or accidental disturbance. A totalising meter checks amount drained over certain periods. Salt concentration is easily checked from a sample tap. Components are assembled using three-part fittings to enable any component to be cleaned or checked. A low-voltage power supply with insulated transformer ensures safe operation.