Whirlpool (WHES) and GE cabinet softeners from big-box stores: quick sheet

Water passes through the valve and resin and exits through the outlet port, where a turbine with a magnet spins past a sensor. The board counts gallons and, using the programmed hardness and the model's capacity, decides when to regenerate (normally overnight). Many models adjust the salt dose and timing automatically (marketed as salt-saving or demand control).

A recharge (regeneration) is a series of cam positions: fill, brining, backwash and fast rinse, though the exact order varies by model. The motor rotates the cam; a position switch tells the board when each position is reached. If the switch never changes state in the expected time the board posts an E-code (E1/E3/E4 on Whirlpool) and stops.

Brine draw depends on the nozzle and venturi assembly on top of the valve: water forced through the nozzle creates suction that pulls brine from the cabinet into the resin. Sand, silt or iron in the nozzle, a misaligned gasket, a plugged flow plug or a restricted drain hose all stop brine draw and give hard water with a salt tank full of water.

The control keeps settings through short outages (power-outage memory); after a long outage the time flashes and must be reset. Errors are cleared by unplugging, fixing the cause, and plugging back in; the Whirlpool manual says to wait about 6 minutes to see whether the code returns.