Water Softener Control Valves Explained

What the valve does

The control valve sits on top of the resin (mineral) tank and connects to your plumbing, usually through a bypass. In service it sends hard water down through the resin and soft water out to the house. When the resin is used up, the valve runs a regeneration: it rinses the resin with brine drawn from the brine tank, then flushes it to drain.

On a Fleck 5600SXT, the Fleck service manual (42684 Rev B) lists the downflow sequence as Backwash, Brine draw and slow rinse, Rapid rinse, Brine tank fill, then Service. Inside the valve, a motor moves a piston through a stack of seals and spacers to open each flow path in turn. An injector (venturi) creates the suction that pulls brine from the brine tank, and a drain line flow control limits how fast water goes to drain.

The valve also holds the settings that decide how much soft water you get between regenerations: hardness, capacity, reserve and the regeneration time. The settings guide explains each one.

Metered vs timer

The main difference between valves is how they decide when to regenerate.

• Metered (demand) valves count the gallons passing through a flow meter and regenerate when the remaining capacity runs low. Salt and water use follow your actual consumption. On the 5600SXT, the control type options include Fd (meter delayed, which waits for the set regeneration time) and FI (meter immediate), per the 42684 manual.
• Timer valves regenerate on a fixed schedule of days, whatever you used. On the SXT board those are the time-clock (tc) and day-of-week (dAY) control settings.

A timer valve is simple, but it has to be set for heavy-use days, so it tends to regenerate more than needed in quiet weeks. A metered valve adjusts to what the house actually uses. Even on a metered valve, a day override sets the longest gap allowed between regenerations; on the 5600SXT, Pentair's manual (4005293 Rev B) allows Off or any value up to 99 days. For how to choose an interval, see how often a softener should regenerate.

Common valve families

Brand names matter here only because they tell you which parts and manuals fit. These heads are sold on their own as replacement valves.

For the Fleck 5600SXT, Quality Water Treatment sells the Fleck 5600SXT 3/4" electronic meter valve (sold by Quality Water Treatment, our store) as a control head that replaces the older 5600SE, from $469 (October 2026). The 42684 manual sets its working range at 20 to 125 psi and advises a pressure-reducing valve when daytime pressure tops 80 psi; keep it away from freezing spots and anywhere above 110 F. At full rated flow, Pentair's figures show roughly 14-15 psi lost through this valve, and less at everyday household flow. Other heads, such as Clack or SoftPro valves, carry their own ratings in their own manuals.

The SoftPro Elite valve uses a 1-inch body. The store lists vacation mode, proportional brining, automatic reserve, variable backwash, automatic regeneration and automatic refresh among its settings. If you are replacing the head on a SoftPro Elite softener, Quality Water Treatment sells the SoftPro Elite softener control valve (sold by Quality Water Treatment, our store) on its own, from $493 (October 2026).

Repair or replace

Most valve faults are wear, not failure of the whole head. Quality Water Treatment's 5600SXT install guide calls for a yearly service of the valve's piston, seals and spacers, using Fleck kit 60010307.

Signs that point to the valve, from the Fleck manual's troubleshooting table (42684 Rev B):

1. Hard water with salt in the tank. Possible internal leak at the seals, spacers or piston, or a plugged injector screen.
2. Drain runs all the time. The valve is not positioning correctly, there is debris in the control, or it is leaking internally.
3. Fails to draw brine. Look at the injector and its screen, the drain line flow control, an internal leak, or water pressure too low to drive the injector (the manual's minimum is 20 psi).
4. Error codes on the display. Meanings differ between board versions, so read them against your manual. The 5600SXT programming guide lists the codes by manual number.

Clean the injector before replacing anything; the injector cleaning guide has the Fleck procedure. Safety first: switch to bypass, then, as the Fleck manual directs, nudge the control into Backwash for a moment to bleed off pressure, return it to Service and pull the plug before you open anything.

Replace the whole head when the body is cracked, parts for an old model are hard to find, or the cost of a board, motor and seal kit approaches a new valve. When you do, match the valve to your tank thread, distributor tube, pipe size and bypass. For a Fleck head, Quality Water Treatment's listing notes the 5600SXT replaces the older 5600SE. Once the valve is back together, the Fleck manual has you inspect all sealing points for drips, testing the drain seal while the valve sits in Backwash; the leak guide covers what to do if one drips.

Common questions

Related guides

• SettingsSoftener settings overview
• SettingsWater softener parts explained
• FixWater softener troubleshooting