The most-referenced DIY installation guide for America's most popular water softener valve — from Discount Water Softeners, a team that installs these daily. 12 steps, complete programming reference, official error codes, and the mistakes that cause most failures.
The Fleck 5600SXT is genuinely a set-and-forget system once programmed correctly. Getting there requires two things most installers skip: testing actual water hardness in GPG (not guessing), and confirming INLET connects to the hard water supply and OUTLET to the house. Reversing these produces a system that runs perfectly and delivers unsoftened water to every tap. The drain line air gap and the overflow line as a separate drain are the other two installation requirements that prevent the most common failures.
Sizing formula: (people × gallons/day per person × hardness GPG) × days between regenerations = minimum capacity. A 48,000-grain unit regenerating every 7–10 days is the most common configuration for a 3–4 person household with moderately hard water. Get your hardness from a water test — don't guess.
| Capacity | Best for | Salt per regen | Price range |
|---|---|---|---|
| 24,000 grains | 1–2 people, 5–10 GPG, 1 bathroom | 6–8 lbs | $400–$500 |
| 32,000 grains | 2–3 people, 10–20 GPG, 1–2 bathrooms | 8–10 lbs | $500–$600 |
| 48,000 grains | 3–5 people, 10–25 GPG — most popular | 10–14 lbs | $600–$750 |
| 64,000 grains | 4–8 people, 20–40+ GPG, well water with iron | 14–18 lbs | $750–$900 |
The softener must go after any iron or sediment pre-filters but before the water heater. For well water with an acid neutralizer: the acid neutralizer adds 4–6 GPG of dissolved calcium — program the softener with the post-neutralizer hardness reading, not the well water reading.
| Water source | Correct equipment sequence |
|---|---|
| Municipal water | Main shutoff → Sediment filter (optional) → Softener → Water heater → House |
| Well (no iron) | Well → Pressure tank → Sediment filter → Softener → Water heater → House |
| Well (with iron) | Well → Pressure tank → Sediment → Iron filter → Softener → Water heater → House |
| Well (low pH + iron) | Well → Pressure tank → Sediment → Acid neutralizer → Softener → House |
Discount Water Softeners ships the 5600SXT with resin pre-loaded in the tank — no resin loading step required. This sequence is structured so you don’t have to redo steps: faucet and drain connections before mounting the housing.
Close the main water supply shutoff valve completely. Open a downstream faucet to bleed pressure until flow stops. Place a bucket under the installation point before proceeding.
Place the resin tank at the installation point — confirm it is level; an unlevel tank causes uneven resin bed distribution. Position the brine tank within 8 feet of the resin tank. Confirm the distributor tube is centered and seated in the bottom basket before threading on the control valve.
Hand-thread the 5600SXT control valve clockwise onto the resin tank. Tighten firmly by hand — do not use pipe wrenches on the plastic valve body. The valve must seat fully against the tank neck O-ring. Confirm the bypass valve is in BYPASS position (handles perpendicular to valve body) before making any plumbing connections.
INLET connects to the incoming hard water supply. OUTLET feeds soft water to the house. This is the most common installation error — verify flow direction arrows on the bypass valve before tightening. Wrap all male NPT threads with 3 layers of Teflon tape; hand-start, then tighten 1.5–2 additional turns. Do not overtighten plastic bypass valve ports — snug plus one full turn is sufficient.
Connect 1/2” drain tubing to the main drain fitting on the control valve. Run to a floor drain or utility sink. Air gap required: drain line end must terminate above the water level and must not be submerged — a submerged drain line creates a siphon that continuously drains the resin tank. Maximum run: 20 feet horizontal, 8 feet vertical elevation; use 3/4” tubing for longer runs.
Push the 3/8” black brine tubing firmly into the brine port on the control valve front (push-fit connection). Route to the brine tank and thread the compression fitting onto the float assembly — hand-tight plus 1/4 turn only. Confirm the brine well is fully seated at the bottom of the salt tank before connecting.
The overflow line is a safety device, not optional. Connect 1/2” tubing to the overflow elbow on the side of the brine tank and run to a separate floor drain — never into the main backwash drain line. The overflow line is not pressurized and must drain entirely by gravity on a continuous downhill slope. A correctly plumbed overflow line is the difference between a minor float failure and a flooded utility room.
Add 1–2 gallons of water to the brine tank (around the brine well, not into it). Then add 1–2 bags (40–80 lbs) of evaporated salt pellets. Use pellets or solar salt — avoid rock salt (high impurity content clogs injectors). Do not fill the brine tank completely for the first startup; add enough for 3–6 regenerations and top off once confirmed operational.
Plug in the power adapter. Press SET UP/DOWN to set current time; press EXTRA CYCLE to advance. Set Regeneration Time (RT) — 2:00 AM default is correct for most homes. Set Hardness (H) to your actual tested GPG (add 3–5 GPG per 1 ppm iron if iron is present). Set Capacity (C) and Brine Fill (BF) per the chart included with your specific unit size. Set Day Override (DO) to 7 days. Press EXTRA CYCLE to exit. Display will show gallons remaining until next regeneration.
Slowly rotate the bypass valve handles to SERVICE position (parallel to valve body) — move 1/4 turn at a time to allow the resin tank to fill gradually. Filling slowly prevents channeling in the resin bed. Allow 1–3 minutes for water to fill and air to purge. Once pressure equalizes, the system is fully charged.
Press and hold the EXTRA CYCLE button for 5–10 seconds until the display shows BW (backwash). Confirm water is flowing to the drain. Monitor each stage: BW → BD → SR → RR → BF. Check all fittings for leaks during the backwash stage — this is the highest-pressure moment. Allow the full cycle to complete (90–120 minutes). The resin bed settles, manufacturing residue is flushed, and all connections are confirmed leak-free under full pressure.
Run cold water at the kitchen faucet for 1–2 minutes to flush the distribution lines. Test with the included hardness test strip — result should read 0 GPG. Check under the installation area at 30 minutes and 24 hours for any new drips. Verify the display shows gallons remaining (not an error code) and the Flow Indicator flashes when water is running.
User Programming Mode (most homeowners only need this): hold Up + Down for 5 seconds while in service mode.
Master Programming Mode (full system configuration): set display to exactly 12:01 PM, press Extra Cycle to exit, then hold Up + Down simultaneously until Programming icon appears.
| Code | Parameter | What to set | Why it matters |
|---|---|---|---|
| H | Feedwater hardness | Tested GPG + 3–5 per 1 ppm iron | Core parameter — too low = hard water breakthrough; too high = wasted salt |
| RT | Regeneration time | 2:00 AM (default — keep it) | Must run when no water demand expected |
| DO | Day override | 7 days maximum | Forces regeneration to prevent bacteria growth in depleted resin |
| C | Unit capacity | Per manufacturer chart for your tank size | Sets gallons treated per cycle; sets salt efficiency |
| BF | Brine fill time | Per manufacturer chart for your system | Controls water volume added to brine tank; must match salt dose |
| VT | Valve type | dF1b (downflow single backwash — standard) | Changes regeneration cycle sequence; do not change unless directed |
| CT | Control type | Fd or FI (meter delayed or immediate) | Sets on-demand metered operation; do not set to time clock |
| FM | Flow meter type | P0.7 (paddle wheel 3/4”) — most Discount WS units | Must match the actual meter shipped; incorrect setting causes wrong regeneration timing |
Iron correction example: 15 GPG hardness + 2 ppm iron → program H = 21–25 GPG. Re-test well water hardness annually — groundwater hardness can shift seasonally.
Enter: hold Up + Extra Cycle for 5 seconds while in service. Press Up to advance through readings.
| Code | What it shows | How to use it |
|---|---|---|
| FR | Current flow rate (GPM) | Confirms meter is reading flow; Flow Indicator on main display also flashes |
| PF | Peak flow since last regeneration | Confirms unit is adequately sized for household peak demand |
| HR | Hours in service since last regeneration | Unusually high hours indicates a slow leak, running toilet, or irrigation line |
| VU | Volume treated since last regeneration | Compare against C÷H (capacity/hardness = gallons per cycle); confirms correct regeneration volume |
| SV | Software version | Record before contacting Pentair support: 800.279.9404 |
| Mistake | What goes wrong | Prevention |
|---|---|---|
| Inlet and outlet reversed | System runs perfectly; house gets unsoftened water throughout | Verify flow direction arrows before tightening any fitting |
| Drain line submerged | Siphon continuously drains the resin tank; display shows constant regeneration | Air gap required — drain end must terminate above water level |
| Overflow into backwash drain | Backwash pressure forces water back into brine tank; floods utility room | Overflow line to a completely separate, gravity-only drain |
| Incorrect hardness programmed | Under-programmed: hard water breakthrough. Over-programmed: wasted salt and water | Test hardness before programming; add iron correction factor |
| Skipping first manual regeneration | Manufacturing residue in resin; air pocket in distributor tube; off-taste water | Always run a full manual regeneration after installation |
| Overtightening plastic bypass ports | Bypass valve body cracks; immediate water leak at connection | Snug plus one turn with Teflon tape; never use pipe wrenches on plastic |
| Brine tank not level | Float mechanism binds; fails to shut off brine water inflow; overflow | Confirm level before connecting brine line |
| Drain run too long or too high | Backpressure causes incomplete backwash; resin bed becomes fouled over time | Max 20 ft horizontal, 8 ft vertical; use 3/4” tubing for longer runs |
| No day override set | Low-use periods (vacation) leave resin depleted for weeks; bacteria colonize bed | Set DO to 7 days maximum |
From the official Fleck 5600SXT Downflow Service Manual (Pentair document 42684 Rev H). For Error Codes 0, 1, and 3 that recur after attempted repair: Pentair Customer Care 800.279.9404 or tech-support@pentair.com.
| Code | Error type | Cause | Recovery |
|---|---|---|---|
| 0 | Cam Sense Error | Valve drive took longer than 6 minutes to advance to next regeneration position | Unplug; inspect powerhead and cam switches; verify piston travels freely; if recurs contact Pentair |
| 1 | Cycle Step Error | Unexpected cycle input; often incorrect VT or CT settings | Unplug; verify Valve Type (VT) and Control Type (CT) in Master Programming; step through manual regen; if recurs contact Pentair |
| 2 | Regen Failure | System has not regenerated in 99+ days (7 days on Day-of-Week control) | Run a manual regeneration to clear; verify flow meter is reading (watch Flow Indicator); check C, DO, and FM settings |
| 3 | Memory Error | Control board memory failure | Perform Master Reset (hold Extra Cycle while powering up); reconfigure all settings; if recurs replace circuit board or contact Pentair |
| UD | Upper Drive Sync | Power failure during installation or programming | No action required — valve automatically recovers |
Soft Reset: Hold Extra Cycle + Down for 25 seconds in service mode. Resets all parameters to system defaults except volume remaining and days since last regen. Use after accidental Master Programming changes.
Master Reset: Hold Extra Cycle while plugging in. Resets ALL parameters including volume remaining. Re-enter all settings via Master Programming after performing a Master Reset.
All causes and corrections drawn directly from Pentair document 42684 Rev H.
| Cause | Official correction |
|---|---|
| Bypass valve open | Close bypass valve; handles must be parallel to valve body (service position) |
| No salt in brine tank | Add salt; maintain level above water level at all times |
| Injector screen plugged | Remove and clean injector screen; replace if damaged (most common 5600SXT service call) |
| Insufficient water flowing to brine tank | Check BF programming; clean brine line flow control (BLFC) if plugged |
| Hot water tank hardness | Hard water from before installation remains in the heater — repeated flushing is required; not a system failure |
| Internal valve leak | Replace seals and spacers (Part No. 60125) and/or piston assembly (60102-71) |
| Cause | Official correction |
|---|---|
| Drain line flow control (DLFC) plugged | Clean DLFC washer on drain port of control valve — most common cause of brine draw failure |
| Injector nozzle or throat plugged | Clean injector; replace if worn or damaged |
| Line pressure too low (<20 PSI) | Minimum 20 PSI required for regeneration; 40–60 PSI optimal; confirm and increase supply pressure |
| Internal control leak | Replace seals, spacers, and piston assembly; see service instructions |
| Problem | Cause | Official correction |
|---|---|---|
| Loss of water pressure | Iron buildup in supply line or inside valve; debris from recent plumbing work | Clean supply line; bypass softener and clear valve body; add sediment pre-filter upstream |
| Excessive water in brine tank | Plugged DLFC or injector; timer not advancing through brine draw; foreign material in brine valve | Clean DLFC washer; clean injector; replace brine valve seat if needed |
| Drain flows continuously | Valve not advancing to next position; foreign material in valve body; internal piston leak | Check timer and cam switches; clear valve body; replace piston assembly |
| Iron in conditioned water | Fouled resin bed | Verify BW, BD, and BF cycles operating correctly; increase regeneration frequency; add iron resin cleaner to brine tank before manual regen |
| Resin loss through drain | Air in well system; improperly sized DLFC | Confirm well has proper air eliminator; check DLFC flow rate against specification; replace washer with correct size |
Properly maintained 5600SXT systems routinely operate 15–25 years without valve replacement. The two most important routine tasks: keep salt in the brine tank and check monthly for salt bridges.
| Task | Frequency | Cost |
|---|---|---|
| Add salt to brine tank | As needed — check monthly; add when salt drops below 1/3 full | $8–$15 per 40 lb bag; 1–3 bags/month typical |
| Check for salt bridges | Monthly | No cost — break crust with a broom handle if present |
| Clean brine injector and screen | Every 1–2 years; sooner if low-pressure symptoms appear | Injector kit $5–$10 |
| Sanitize resin bed | Annually or when sulfur odor appears | Resin cleaner packet $5–$10 |
| Clean brine tank | Every 2–3 years | No material cost — diluted bleach solution + rinse |
| Check resin for iron fouling | Annually if iron is in source water | Resin cleaner $10–$20; full resin replacement $50–$150 |
| Inspect drain and brine lines | Annually | Replacement tubing $5–$15 |
| Verify programming after power outage | After any outage >48 hours | No cost — only time of day may need resetting; all other settings in non-volatile memory |
| Component | Part number | Notes |
|---|---|---|
| Seal and spacer kit (complete) | 60125 | Replace when internal leaks develop; every 5–10 years as preventive maintenance |
| Piston assembly (downflow) | 60102-71 | Complete piston for 5600SXT downflow; replace if internal leak persists after seal kit |
| Injector assembly | 60084-XXXX | Specify injector number, DLFC size, BLFC size; #1 White injector is standard residential |
| Plastic bypass valve (3/4”) | 60049 | Standard residential bypass |
| Stainless bypass (1”) | 60041SS | For 1-inch pipe connections |
| Drive motor | 16944 | 24V, 60Hz, 2 RPM; replace if valve fails to advance through regeneration positions |
| Safety brine valve 2310 | 60014 | Complete float assembly replacement |
| Pentair Customer Care | 800.279.9404 | tech-support@pentair.com · pentairaqua.com/pro |