Quick Answer: If your softener runs on a Fleck 5600 and the tank and resin are still good, a new Fleck 5600SXT digital metered head is the replacement most homes need. Bigger tanks (or a softener that also has to backwash hard) should step up to the Fleck 2510SXT. Clack WS1 owners usually shouldn't buy a whole new valve at all: the genuine Clack WS1 rebuild kit replaces the parts that actually wear out.
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Here's the uncomfortable truth about softener control valves: a lot of them get thrown away when only a small, cheap part inside was bad. A head that's leaking to drain, stuck mid-cycle or showing a blank screen might need replacing. It might also need a seal kit, a piston, a motor or a fuse. So this guide does two jobs. It helps you figure out whether you need a new head, and if you do, which one fits the tank you already own.
One thing up front: the products below are the valve itself (or the rebuild parts). None of them includes a mineral tank or resin. If your resin is shot too, the math changes. Our guide on whether to repair or replace an old water softener walks through that call.
In this guide
- First, rule out the cheap fixes
- How we narrowed the field
- Quick fit table
- 1. Fleck 5600SXT Replacement Valve: best for most homes
- 2. Fleck OEM 560006-011 5600SXT: best when you want the exact Pentair part number
- 3. Fleck 2510SXT Digital Metered Control Head: best for bigger tanks
- 4. Fleck 5600 Analog Mechanical Metered Valve: best for replacing an old mechanical Fleck
- 5. Genuine OEM Clack WS1 Interior Rebuild Kit with Wrench: best for Clack owners
- Fleck or Clack: which way should a valve swap go?
- Install day: what actually goes wrong
First, rule out the cheap fixes
Before you order anything, run through this list. It takes 20 minutes and saves a lot of people the cost of a new head.
- Blank or frozen display? Check the transformer at the outlet, the outlet itself (GFCI tripped?) and the plug-in connection at the board. A dead wall adapter looks exactly like a dead valve. More on that in our error-code and blank-display guide.
- Water running to drain nonstop, or hard water sneaking through? On both Fleck and Clack valves, that's the classic sign of worn seals and spacers or a scored piston. The valve body is usually fine.
- Won't advance through a regeneration? Could be the drive motor, a cam/gear problem, or a bad board. All are sold separately.
- Bypass won't turn or leaks? That's the bypass, not the head. It's a separate part, and it often just needs new O-rings and silicone grease.
If you aren't sure which part of the valve does what, how a water softener control valve works is the quickest primer. Then servicing a water softener control valve covers pulling the piston and seal stack.
When a new head really is the right call
Replace the whole valve when:
- The valve body is cracked, or the threads on the tank adapter are damaged.
- You've got an old mechanical timer valve and want metered (demand) regeneration. That one change can cut salt and water use noticeably because the softener stops regenerating on a calendar.
- Repair parts for your valve are hard to find, or you'd be replacing the board, motor and seals anyway.
- Your softener came from a dealer with a proprietary valve, and you've decided to convert the tank to an open-market Fleck or Clack head. That's doable if the tank and distributor fit, but check them before you buy.
How we narrowed the field
We stuck to valve families that DIYers can actually service for the next 15 years: Fleck (Pentair) and Clack. Both have deep parts availability, published manuals, and big communities of installers. We left out no-name "5600SXT-style" clones. They're often cheaper, but the parts don't always swap with genuine Fleck pieces, and that defeats the point of buying a common valve. For each pick we checked the published specs (flow, backwash, tank range, power backup) against the listing and manufacturer documentation, and we only included Amazon listings we could match to the exact model.
Quick fit table
| Valve | Control type | Best tank range | Why pick it |
|---|---|---|---|
| Fleck 5600SXT (paddlewheel meter) | Digital, metered | Up to ~12" softener tanks (Pentair sheet) | Most common residential head; easy parts |
| Fleck 560006-011 (OEM) | Digital, metered | Same as above | Exact Pentair part number |
| Fleck 2510SXT | Digital, metered | Larger tanks, filters | Stronger backwash than the 5600 |
| Fleck 5600 mechanical | Mechanical meter | Up to 13" softener tanks (seller listing) | Swapping like-for-like, no circuit board |
| Clack WS1 rebuild kit | N/A (internal parts) | Your existing WS1 | Fixes leaks and bypass without a new valve |
1. Fleck 5600SXT Replacement Valve: best for most homes
If you have a typical 32,000–48,000 grain softener in a 9" or 10" tank, this is the head we'd put on it. It's the digital metered "on demand" version with a paddlewheel meter, so it counts gallons and regenerates when the resin is actually near exhaustion instead of every few days by the clock.
The specs Pentair publishes for the 5600SXT are what make it the default. The technical sheet lists a 24-volt valve with a 48-hour capacitor backup for the clock and programming, with the setup parameters held for years. It recommends tanks up to 12 inches in diameter for softeners. Retail installers commonly quote around 20 gpm of service flow. That's plenty for a two-bathroom house and most three-bathroom homes that don't run everything at once.
Who it's for: Anyone replacing a dead 5600 or 5600SXT, or upgrading an old timer-based 5600 to metered.
The downside: The 5600's backwash is gentle. Mid Atlantic Water, a Fleck dealer, puts it at about 7 gpm against 17 gpm for the 5800. That's fine for softener resin. It isn't the head to choose if your tank also holds heavy filter media or you're feeding it a lot of iron.
Install notes: You'll need to set the injector, drain line flow control (DLFC) and brine line flow control to match your tank diameter. If you're moving parts from your old 5600, check that they match what's in the new head before you thread it on. Program hardness in grains per gallon and the system capacity in grains, then let the meter do the rest.
2. Fleck OEM 560006-011 5600SXT: best when you want the exact Pentair part number
This is the same valve family as pick #1, listed under Pentair's OEM part number 560006-011. The listing describes a 24V electronic meter-demand head rated at 20 gpm with a 48-hour power backup, usable for downflow or upflow, and it's sold without a tank. Why list it separately? Some homeowners, and plenty of property managers, want a head that matches a specific part number on an invoice or a service record. If a plumber or a past dealer installed a 5600SXT and you're swapping like for like, buying by part number removes guesswork.
Who it's for: People matching a documented existing valve, or anyone who'd rather buy by the OEM number than by a reseller's listing title.
Who should skip it: If you're happy with any genuine 5600SXT, pick #1 is simpler. The difference is in how the listing is described, not in what the valve does.
3. Fleck 2510SXT Digital Metered Control Head: best for bigger tanks
The 2510SXT uses the same SXT programming and display as the 5600SXT, so if you already know one, you know the other. What changes is the hydraulics. The 2510 pushes a stronger backwash, which is why you'll see it on 64,000 and 80,000 grain softeners, iron-reducing softeners, and backwashing filters. Fleck dealers point to it whenever the media bed is large or dirty enough that a 5600 can't lift and clean it properly.
Who it's for: Homes with 12" or larger tanks, high-flow households, and softeners on well water that sees some iron or sediment.
The downside: It's a bigger valve and it uses more water per backwash. On a small 1 cubic foot softener, that's wasted water and money. Don't "upgrade" a small system to a 2510 just because it sounds more serious. If your tank is 10" or smaller, stay with the 5600SXT.
One practical check: The 2510 and 5600 use different bypass valves and different internal parts. If you're switching from a 5600 to a 2510, budget for the matching bypass and plumbing adapters. Your old 5600 bypass won't bolt on.
4. Fleck 5600 Analog Mechanical Metered Valve: best for replacing an old mechanical Fleck
Some people want what they had: a mechanical meter dial and timer, no circuit board, no LCD. Older mechanical Fleck 5600 heads have been running in basements for decades, and this analog metered version still regenerates based on gallons used, through a paddlewheel meter. You set it with a control knob and dials instead of buttons.
Per the seller's listing, it's a genuine Fleck 5600 analog metered valve rated for up to 20 gpm service flow (at a 15 psi drop) with the right tank, for softener tanks up to 13" in diameter. It ships set up for a 9" (1 cubic foot, 32,000 grain) softener, with 2.0 and 2.4 gpm drain line flow controls and directions for reconfiguring it for a larger tank. It includes a genuine Fleck 3/4" MPT yoke and carries a 5-year manufacturer warranty.
Who it's for: Owners swapping out a worn mechanical 5600 who want the same setup and the same feel, or people who've lost patience with boards that die after a lightning strike or a power surge. If your old head is a mechanical 2510, this isn't a drop-in swap: the 2510 uses a different bypass and internals, so look for a 2510 body or step up to the 2510SXT above.
Honest downsides: Setting a mechanical meter takes more care than typing numbers into an SXT screen. You'll be reading the manual. It also gives you less information. There's no flow display and no regeneration history. If you've never had a mechanical Fleck, the 5600SXT is the easier choice.
5. Genuine OEM Clack WS1 Interior Rebuild Kit with Wrench: best for Clack owners
We looked hard for a standalone, plainly listed Clack WS1 head on Amazon that we could match to an exact model, and we couldn't verify one. That's partly because Clack sells mostly through water-treatment dealers. It's also partly because, for most Clack owners, a whole new valve is the wrong purchase anyway.
The WS1 is built around a cartridge-style spacer stack and piston that slide out of the front of the valve. When a WS1 starts leaking to drain, letting hardness through, or making odd noises mid-cycle, the stack and pistons are the usual suspects. This kit bundles the genuine Clack spacer stack, the downflow piston and the regenerant (brine) piston with the Clack service wrench. In other words, it replaces the wear parts and leaves you with what is functionally a rebuilt valve.
Who it's for: Anyone with a Clack WS1 that powers up and cycles but leaks, drains constantly, or passes hard water.
Who it won't help: If the WS1 board is dead, the motor won't turn, or the valve body is cracked, this kit doesn't fix that. Those are separate parts. Also double-check you have a WS1 (1-inch), not a WS1.25 or WS1.5. Those use different seal stacks.
Fleck or Clack: which way should a valve swap go?
If you already have a Fleck, stay with Fleck. Your tank, distributor and plumbing were set up for it, and a 5600SXT-to-5600SXT swap is the easiest DIY job in this whole category.
If you have a Clack WS1, rebuild it before you think about replacing it. The WS1 is well liked by installers for its diagnostics and adjustable cycles, and its parts are designed to be swapped from the front without pulling the valve off the tank.
If you have a dealer valve with no parts support (or a big-box unit whose maker has stopped supporting it), converting to a Fleck head is reasonable, but only if three things check out:
- Tank opening: most residential mineral tanks use the standard 2.5" thread. Confirm yours.
- Distributor tube: the riser has to fit the valve's pilot and stick up to the right height. Cut it flush with the top of the tank opening, unless your valve's manual says otherwise.
- Tank size vs. valve: 5600SXT for roughly 12" tanks and under, 2510SXT for bigger ones.
Get any of those wrong and you'll get leaks, resin in the plumbing, or poor regeneration, none of which is the valve's fault.
Install day: what actually goes wrong
Most replacement-valve headaches come from the same handful of mistakes:
- Forgetting the bypass. Put the system in bypass and depressurize it before you touch anything. If the bypass itself is seized, sort that out first. Our stuck bypass guide covers it.
- Wrong DLFC or injector. Too small and the bed doesn't get cleaned. Too large and you waste water or pull resin into the drain.
- Skipping the slow start-up. Open the inlet a crack, let air purge through the drain during a manual backwash, then go to service. Opening it fast can blow resin up the distributor.
- Not reprogramming. A new SXT head comes with factory defaults. Enter your hardness, capacity, regeneration time and reserve, or it'll regenerate at the wrong time and the wrong rate.
If you aren't comfortable cutting into plumbing, a local plumber can do a like-for-like head swap fast. It's one of the simpler softener jobs they see.