What device is responsible for shutting off water in the absence of overflow?

The brine tank float control is crucial for regulating the water level in the brine tank of a water softener. Its primary function is to prevent overflow by shutting off the water supply when the brine tank has reached a certain level. This mechanism operates by using a float that rises with the water level; once it reaches a predetermined height, it signals the water supply to stop, thus avoiding any overflow situations.

This control is especially important in ensuring that the brine tank maintains the correct concentration of salt and water for effective regeneration of the water softening process. If the float control fails or is improperly set, it could lead to excessive water entering the brine tank, potentially causing spillage or dilution of the brine solution, which would undermine the efficiency of the softening system.

Other devices listed, such as the chemical feed pump, contact tank, and timer-controlled systems, have distinct functions that do not primarily focus on preventing overflow. The chemical feed pump is designed for injecting chemicals for water treatment, while the contact tank holds water to allow for the appropriate contact time with treatment chemicals. Timer-controlled systems manage the timing of various processes but do not directly manage the water levels in a brine tank.