Abstract: A floor scrubber has rotating brushes for scrubbing a floor, drive motors for the brushes, and a brush height control circuit for raising and lowering the brushes in accordance with a desired brush pattern. The scrubber includes a solution tank, a recovery tank and a detergent tank for application and recovery of the cleaning solution. A solution tank pump, a detergent tank pump and a fan for use in vacuuming used cleaning solution into the recovery tank are each connected to their respective tanks. There are actuating means connected to the brush drive motors, pumps, fan and brush height control circuit. Sensors monitor the solution tank, recovery tank and detergent tank, as well as the speed of the floor scrubber. A start signal for the actuating means is only provided when the sensors determine certain prestart conditions have been met in the solution tank, recovery tank, detergent tank and a certain predetermined speed has been reached for the floor scrubber.