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How to Rebuild a Water Softener

Updated: Jun. 30, 2017

Rebuild your control valve in an hour

FH11JAU_REBSOF_02-2Family Handyman
Rebuild the control valve on your water softener and restore your softened water flow. It only takes an hour once you find the correct rebuild kit.

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Step 1: Remove the old parts

Photo 1: Remove the main piston

Grab the piston by the metal tang and yank it straight up (the uppermost seal may come out with the piston). Toss the piston.

Photo 2: Remove the valve innards

Stick your finger down into the control valve and pull out the four spacers and five seals. Toss them.

A bum water softener control valve can cause the unit to leak or stop producing soft water. A leak automatically means a rebuild, but if you’ve run out of soft water, first check the power at the receptacle. If the receptacle works and your softener is more than five years old, chances are good that you’re due for a control valve rebuild. Water softener repair pros charge about $200 to do that. But you can do it yourself in about an hour and for less than $60. I’ll show you how to rebuild one of the most common valves (the Fleck 5600 series) and direct you to a Web site for rebuild instructions for other brands.

It’ll take some detective work to find the make and model of your control valve because they don’t have identifying labels. So take a photo of your valve and go to Click on “I.D. Your Control Valve” and match your photo to the valves there. If you have a Fleck control valve, buy a complete rebuild kit and follow the instructions here. If you have a different brand, locate the parts and rebuild instructions on the site’s menu.

Start the rebuild by relieving the internal water pressure. Turn the bypass valve to the “bypass” position and rotate the dial to the “backwash” position. Unplug the power cord. Then remove the back cover, the housing screws and the screw in the center of the main piston. Tilt the housing and lift it off. Remove the hold-down plate screws and the plate. Then grab the piston and pull it straight up (Photo 1). Next, remove the spacers and seals (Photo 2).

Step 2: Install the new parts

Photo 3: Replace the brine valve

Pop out the old brine valve and check to make sure the bottom O-ring comes with it. Then push the new valve into the bore.

Photo 4: Load in the new valve parts

Drop a rubber seal down into the valve body. Then alternate spacers and seals, finishing with a seal at the top.

Remove the old brine valve and install the new one (Photo 3). Then install the new seals and spacers (Photo 4). Insert the new piston and install the hold-down plate. Reinstall the housing, turn on the water and check for leaks. Then turn the dial to put the unit into a manual regeneration and check again for leaks.

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • 4-in-1 screwdriver

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.

  • Control valve rebuild kit