Water Softener Owner's Guide

Fleck 5600SXT Water Softener: Complete Owner's Guide

Everything you need to know about the most widely installed residential water softener valve in America: sizing, installation, programming, maintenance, and troubleshooting. Written from 30+ years of field experience installing and servicing Fleck systems.

Want the full picture on water softeners? Start with our Complete Guide to Water Softeners.

What Makes the Fleck 5600SXT the Industry Standard

The Fleck 5600SXT is manufactured by Pentair (formerly Fleck Controls), a company that has been building water treatment valves for over 70 years. When water treatment professionals talk about "the Fleck," this is the valve they mean. It is the most widely installed residential water softener control valve in North America, and for good reason.

Here is what sets it apart:

• Metered (on-demand) regeneration. The "SXT" in the name stands for the digital metered control. Unlike older timer-based softeners that regenerate on a fixed schedule whether you need it or not, the 5600SXT tracks your actual water usage with a built-in turbine meter. It only regenerates when the resin is actually exhausted. This saves salt, saves water, and means the softener adapts to your household's usage patterns automatically.
• Noryl valve body. The valve housing is made from Noryl (a glass-filled polyphenylene oxide), not cheap plastic. Noryl is chemically resistant, dimensionally stable, and handles pressure and temperature swings without warping or cracking.
• Low power consumption. The 5600SXT uses a small transformer that draws minimal power. It maintains time and programming settings during brief power outages via an internal capacitor.
• Universal parts availability. Because the 5600SXT is so widely used, replacement parts (pistons, seals, brine valves, motor assemblies) are available from dozens of suppliers. You will never be stuck waiting on a proprietary part from a single manufacturer.
• Proven track record. We have been installing Fleck softeners for over 25 years. In that time, the 5600SXT has consistently been the most reliable residential softener valve we have used. With proper maintenance, the valve itself typically lasts 15 to 25 years.

Available Configurations and Pricing

The Fleck 5600SXT valve is paired with different tank sizes and resin volumes to create systems at different grain capacities. Here is every configuration we carry, with current pricing:

Single-Tank Systems (Fleck 5600SXT Valve)

Larger Valve Systems (Fleck 2510SXT)

For homes that need higher flow rates (the 2510SXT has a 1-inch porting versus the 5600SXT's 1-inch standard), we offer:

Twin-Tank Systems (Fleck 9100SXT)

Twin-tank softeners use two resin tanks with one control head. While one tank is in service, the other is on standby or regenerating. This means you have soft water 24/7 with zero downtime during regeneration. See our dual-tank water softener guide for a deeper comparison.

Replacement Parts

All systems ship with the resin pre-loaded in the tank and the bypass valve pre-installed on the control head, so you are ready to plumb it in right out of the box. For current pricing on all water softener systems, visit our collection page.

How to Size Your Fleck Water Softener

Getting the right size matters. An undersized softener regenerates too frequently, wasting salt and water. An oversized softener costs more upfront but gives you a longer reserve between regenerations and handles usage spikes better. When in doubt, go bigger. There is no downside to having extra capacity.

The sizing formula is straightforward:

Daily softening demand = People in home x 75 gallons/day x Hardness (GPG)

If you have iron in your water, add 5 GPG to your hardness number for every 1 ppm of iron. This accounts for the additional resin capacity iron consumes.

Then multiply daily demand by 7 (days between regenerations) to get the minimum grain capacity you need.

Here is a practical sizing chart based on household size and hardness levels:

Not sure about your hardness? Our water softener sizing guide walks through the full calculation. Or send your water test to Aidan at support@midatlanticwater.net and he will tell you exactly what size you need.

Installation Walkthrough

The Fleck 5600SXT is one of the most DIY-friendly water softeners available. We did installations for over 20 years before transitioning to a wholesale model, and the majority of our customers now install these systems themselves. Here is how to do it right, from the perspective of someone who has done it over a thousand times.

What You Will Need

• Adjustable wrench and channel-lock pliers
• Teflon tape (yellow gas-rated tape works best; it is thicker)
• 1-inch NPT fittings to match your home plumbing (copper, PEX, or CPVC adapters)
• A nearby floor drain or utility sink for the drain line
• 3/8-inch or 1/2-inch drain line tubing (supplied or available at any hardware store)

Installation Order

If you are installing multiple water treatment systems, the order matters. Here is the correct sequence from the well or water main:

The softener always goes after any acid neutralizer or iron filter. An acid neutralizer will increase your water's hardness by 4 to 6 grains per gallon (because the calcite media adds dissolved calcium), so the softener needs to be downstream to remove that added hardness. See our guide on acid neutralizers and water softeners together for details.

Step-by-Step Installation

1. Choose your location. Pick a dry, level area near the main water line, ideally close to a floor drain. The temperature should stay between 34°F and 120°F. Avoid placing the system where it could freeze.
2. Shut off the water supply and relieve pressure by opening a downstream faucet.
3. Position the tanks. Place the resin tank and brine (salt) tank side by side. The brine tank should be within 8 feet of the resin tank so the brine draw line can reach.
4. Mount the valve head. The Fleck 5600SXT valve threads onto the resin tank by hand. Do not over-tighten. Hand-tight is sufficient; the O-ring creates the seal.
5. Connect the bypass valve. Our systems ship with the stainless steel bypass valve pre-installed. Verify the arrows on the bypass match the inlet/outlet direction. When the bypass knobs are turned so the arrows point toward each other, water flows through the softener. When they are parallel (pointing the same direction), water bypasses the unit.
6. Plumb the inlet and outlet. The inlet is marked with an arrow pointing into the valve. Connect your home's water supply to the inlet side and the house plumbing to the outlet side using 1-inch NPT fittings. Use Teflon tape on all threaded connections.
7. Connect the drain line. Attach the drain line to the drain fitting on the valve head. Run it to your floor drain or utility sink. The drain line should not be submerged in water (air gap required). For best results, keep the drain line run under 20 feet with no uphill runs.
8. Connect the brine line. Push the brine tubing onto the brine fitting on the valve and connect the other end to the brine tank float assembly. This is a push-fit connection; no tools needed.
9. Add salt to the brine tank. Fill the brine tank about two-thirds full with pellet salt (solar salt or evaporated salt pellets work best; avoid rock salt).
10. Open the bypass slowly. Turn the bypass knobs a quarter turn at a time to let water fill the resin tank gradually. This prevents the resin from being disturbed by a sudden rush of water. Once the tank is full and pressure equalizes, open the bypass fully.
11. Run a manual regeneration. Press and hold the regeneration button on the 5600SXT to initiate a manual cycle. This flushes the resin, fills the brine tank with water for the first time, and confirms everything is connected properly. Run through the full cycle (about 90 minutes).
12. Check for leaks. Inspect every connection while the system is under pressure. Tighten any that drip.

We are here seven days a week if you run into anything during installation. Call Aidan at 800-460-5810 for real-time guidance.

Programming Guide

Programming the Fleck 5600SXT is one of the most common questions we get from new owners. The good news: there are really only three settings you need to get right. Everything else can stay at the factory defaults.

Step-by-Step Programming

To enter programming mode on the 5600SXT, press and hold the up and down arrow buttons simultaneously for about 3 seconds until the display changes. Then use the up/down arrows to adjust each setting and the "Next" button to advance through the menus.

1. Set the time of day. Use the up/down arrows to set the current time. Press "Next" to confirm.
2. Set the day of the week. Adjust if needed. Press "Next."
3. Set the hardness (in GPG). Enter your water hardness from your water test. If your raw water tests at 15 GPG hardness and you have 2 ppm of iron, enter 25 GPG (15 + (2 x 5)). Press "Next."
4. Set the capacity. Enter the grain capacity of your system: 32, 48, or 64 (in thousands). Press "Next."
5. Set the regeneration time. This is the time the softener will begin a regeneration cycle when it determines one is needed. Set this to 2:00 AM (or whenever water usage is lowest in your home). Press "Next."
6. Day override. This is a safety feature. If the softener has not regenerated within this many days (regardless of water usage), it will force a regeneration. Factory default is 7 days, which is fine for most homes. Leave it unless Aidan tells you otherwise.
7. Exit programming. The display returns to the main screen showing the current time and gallons remaining.

The display will show the estimated gallons remaining before the next regeneration. As you use water, this number counts down. When it reaches zero, the softener schedules a regeneration for the next occurrence of your programmed regeneration time.

Salt Dosage

The Fleck 5600SXT allows you to set the salt dosage per regeneration. For most residential applications:

• 32,000 grain system: approximately 6 to 8 lbs of salt per regeneration
• 48,000 grain system: approximately 9 to 12 lbs of salt per regeneration
• 64,000 grain system: approximately 12 to 15 lbs of salt per regeneration

The factory default salt settings are a reasonable starting point. If you want to optimize for salt efficiency versus capacity, Aidan can walk you through the tradeoff. There is a sweet spot where you get the most softening per pound of salt without sacrificing too much capacity. For a deeper dive, see our water softener regeneration guide.

Maintenance Schedule

One of the best things about the Fleck 5600SXT is how little maintenance it requires. Here is the complete maintenance schedule:

That is the full list. There are no filters to change, no chemicals to add, and no media to replace (other than eventually the resin, years down the road). The softener is genuinely one of the lowest-maintenance systems in your water treatment lineup. For more detail, see how long water softeners last.

Troubleshooting Common Issues

After selling thousands of Fleck 5600SXT systems and fielding support calls for over two decades, these are the issues we see most often, along with what to do about them.

Hard Water Breakthrough

If your water feels hard again or you are seeing spots on fixtures:

1. Check the salt level. The most common cause is simply running out of salt. Open the brine tank lid and verify there is salt above the water line.
2. Check for a salt bridge. Push a broom handle through the salt. If there is a hollow cavity underneath a hard crust, break up the bridge and wait for the next regeneration.
3. Verify your hardness setting. If your water hardness has changed (common with well water), the softener may be undershooting its regeneration frequency. Test your raw water and update the hardness setting.
4. Check the bypass valve. Make sure the bypass arrows are pointing toward each other (closed position). If a plumber opened the bypass during a service call and forgot to close it, all your water is bypassing the softener.
5. Test the resin. If salt is present, programming is correct, and the bypass is closed, the resin may be exhausted. This typically happens after 10 to 15 years. Replacement resin solves the problem.

Motor Stalling or Valve Stuck in Regeneration

If the valve seems stuck in one position during regeneration and the motor is humming:

• Power cycle the unit. Unplug the transformer for 30 seconds, then plug it back in. Press the manual regeneration button to advance the valve to the next cycle position.
• Check for debris. Sediment or resin beads can jam the piston. If this happens repeatedly, install a sediment pre-filter upstream.
• Piston or seal wear. On older units (15+ years), the piston seals may be worn. A Fleck 5600SXT rebuild kit (piston, seals, spacers, brine valve) costs around $50 to $80 and takes about an hour to install.

Brine Draw Failure (No Water in Salt Tank)

After regeneration, there should be a few inches of water in the bottom of the brine tank. If the brine tank is dry:

• Check the brine line connection. The tubing between the valve and the brine tank float may be kinked, disconnected, or clogged with salt debris.
• Inspect the brine valve and injector. The injector nozzle and throat create the suction that draws brine into the resin tank. If they are clogged, brine draw fails. Remove and clean them with warm water.
• Check drain line flow. If the drain line is kinked or too long (over 20 feet), insufficient backpressure can prevent the venturi effect that drives brine draw.

Water in the Salt Tank is Too High

If water rises above the normal 3 to 6 inch level in the brine tank:

• Check the float valve. The brine tank has a float that controls refill water level. If the float is stuck or misadjusted, the tank overfills.
• Check for a brine line leak. A loose connection can allow continuous water flow into the brine tank.

Low Water Pressure After Installation

If your water pressure dropped noticeably after installing the softener:

• Check for a restricted bypass. Make sure the bypass is fully open.
• Check inlet/outlet orientation. Reversed connections force water to flow backward through the resin bed, creating significant pressure drop.
• Sediment clogging. If your water has sediment, it can pack the top of the resin bed. A pre-filter will prevent this.

For troubleshooting beyond these common issues, see our full water softener troubleshooting guide. Pentair also offers technical support for the Fleck valve at (262) 238-4400. And of course, Aidan is available at 800-460-5810 seven days a week.

Fleck 5600SXT vs. Clack WS1

The two most respected names in residential water softener valves are Fleck (Pentair) and Clack. If you are researching softeners, you have probably seen both recommended. Here is an honest, side-by-side comparison based on our experience with both.

Both are excellent valves. Both are metered. Both use Noryl bodies. The Clack WS1 does have a higher maximum flow rate (27 GPM vs. 20 GPM), which can matter for very large homes or commercial applications.

The reason we chose Fleck as our primary softener valve comes down to a few practical factors: parts availability is unmatched (any plumber can source Fleck parts), the 5600SXT has the longest track record in residential applications, and Fleck allows their products to be sold and shipped directly to homeowners. Clack has restricted their valves from being drop-shipped, which limits availability for DIY buyers.

For a broader comparison of softener options, see our guide on the best water softener systems.

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