Ion-Exchange Water Softener

Overview

The Water Softener removes the calcium and magnesium that make water "hard" and leave scale on pipes, heaters and fixtures. It does this by ion exchange: hard water passes through a bed of resin beads that trade their sodium ions for the hardness ions, and once the bed is loaded, a salt brine regenerates it. The system pairs a Resin Mineral Tank with a Brine Tank, topped by a Control Valve Head and run by an electronic Controller Board.

How it works

In service, household water flows down through the Resin Mineral Tank. Its Ion-Exchange Resin Beads are a strong-acid cation resin: each bead grabs the dissolved calcium and magnesium and releases sodium in exchange, so the water leaving the Riser Tube is soft. A Upper Distributor Basket spreads incoming flow across the bed and a Lower Distributor Basket over a Gravel Underbed collects the treated water while holding the beads back.

Resin has a finite capacity, so the Controller Board counts treated gallons through a turbine Turbine Flow Meter and triggers a regeneration when the bed is nearly spent. The Control Valve Head then re-pipes the system through backwash, brine draw and rinse positions. Its Injector / Venturi, a venturi eductor, sucks saturated brine from the Brine Tank, where salt sits on a grid plate over the water and a Brine Float / Safety Valve sets the fill level and guards against overflow. The strong sodium brine floods the resin and reverses the exchange, stripping off the captured hardness and recharging the beads with sodium. The displaced hardness and spent brine go to drain through the Drain Flow Control and Drain Hose.

A geared Valve Drive Unit indexes the rotary valve between these positions on the controller's command, and the Power Transformer supplies low-voltage power. The Bypass Valve lets you isolate the unit for servicing while the house still gets (untreated) water.