To add detergent bleach or fabric softener, the control sends voltage to the water inlet valve. The valve opens, allowing water to travel to the dispenser system, which dispenses each solution into the tub during the proper cycle. Be aware that using too much detergent can cause deposits to build up in the dispenser housing. This can restrict the flow of water through the system, and prevent the proper amount of detergent from entering the tub. If the dispenser is free of restrictions, but still fails to work, the cause could be low water pressure to the washer, a restricted fill hose, or a problem with the water inlet valve itself. Also, be aware that the system may require a higher water pressure than the 20-PSI minimum to properly flush the solutions from the dispenser.