I have a Kenmore Genius Plus water softener purchased in 1996. The unit will not draw brine from the brine tank during the regeneration process. There are no obstructions in line from the brine tank to the nozzle and venturi. The nozzle and venturi unit was disassembled and was clean. Could one of the seals in the rotary valve be leaking? Has this unit had specific failures such as this? Any help is appreciated.