Circuit and apparatus for controlling a water softener

Claim 1

Apparatus for regenerating the ion exchange bed of a water softener having a regenerating means and a recycling control connected to control the regenerating means comprising, a first pair of resistors, two pairs of spaced electrodes and at least one mounted in the ion exchange bed, one providing a reference and the other sensing, a bridge circuit including said pairs of electrodes and said first pair of resistors, an A.C. power supply signal applied to said bridge circuit, a first comparator receiving a first input from said bridge circuit from the junction point between said reference electrodes and one of said first pair of resistors and a second input from said bridge circuit from the junction point between the other one of said first pair of resistors and said sensing electrodes, a relay with switch contacts operated by said first comparator, a latching circuit connected to said relay to maintain it energized, a timing means capable of being set to selected time periods, and a recycle switch controlled by said timing means and said recycle switch and the switch contacts of said relay connected in circuit with said recycling control including a reset switch connected to said latching circuit for resetting it and wherein said reset switch is controlled by said timing means to reset said latching circuit after said ion bed has been regenerated and including a time delay circuit connected between said first comparator and relay so that said relay is operated only if the output of said first comparator indicates that regeneration should occur for a fixed time period.