Fleck 5600SXT settings: capacity, hardness and regeneration explained

The Fleck 5600SXT settings that decide whether you get soft water are four numbers: unit capacity (C), hardness (H), reserve (RC or SF) and the brine fill time (BF). Enter capacity as the grains your resin removes at your real salt dose, not the box rating: a 1.5 ft³ tank at 6 lb of salt per ft³ removes about 31,500 grains, not 48,000. Enter your hardness plus an iron allowance, keep a reserve of about one day’s water, regenerate in the middle of the night, and set the brine fill so it makes the 9 lb of salt that 31,500 grains assumes.

Every menu name, range and button press below comes from Pentair’s Fleck 5600SXT downflow service manual (form 42684, rev L). Use it to program a Fleck 5600SXT from scratch or to check a dealer’s setup. Where the manual doesn’t give a value, we say so rather than fill the gap.

Before you start: what the Fleck 5600SXT setup needs

Four facts about your own system decide the numbers. Write them down before you touch the buttons, because the control can discard your changes after as little as 60 seconds without a button press (the manual gives both 60 seconds and 5 minutes).

• Resin volume in cubic feet. It’s on the dealer’s invoice or product page, and the tank size is a clue: Pentair’s own 5600SXT systems pair 1.0 ft³ with a 9 x 48 in tank, 1.5 ft³ with 10 x 54 and 2.0 ft³ with 12 x 52, per the performance data sheet in the Pentair 5600SXT softener system manual.
• Hardness in grains per gallon and clear-water iron in ppm, from a lab test. If your report gives hardness in mg/L, divide by 17.1; our guide to reading well water test results shows where to find each number.
• Meter type. The control needs to know which flow meter is fitted (the manual’s job sheet lists a 3/4 in turbine or a 3/4 in paddle wheel).
• Brine line flow control (BLFC) size, in gallons per minute. You need it to turn a salt dose into a fill time. More on that below.

The manual also carries a job specification sheet with blanks for hardness, capacity, tank size, salt setting and every cycle time. If your dealer filled one in, it’s the best record of how your valve was set up.

Fleck 5600SXT settings in master programming

Here is how to program a Fleck 5600SXT, one screen at a time. To enter master programming, set the time of day to 12:01 PM (hold Up or Down until TD shows, adjust, press Extra Cycle). Then hold Up and Down together until the programming icon appears and the DF screen shows. Press Extra Cycle to accept each value and move to the next; pressing it at the last one saves everything. Pentair’s own caution on this page is to contact a water dealer first, and some screens only appear for certain choices.

How to check it worked: after you exit, the display alternates between the time of day and the volume remaining. That volume should equal your capacity divided by your hardness, minus the reserve. If it doesn’t, one of C, H or the reserve is wrong.

Two details trip people up. The capacity range printed in the manual reads “1-999,900 gallons”, but the text above it says to enter grains of hardness for a softener (and a volume only for a filter). And the manual says C and H only appear when CT is set to a metered option, so set CT first.

On an iron filter tank the same valve is set to the Fltr valve type, and C is entered as a volume in gallons rather than grains; this guide covers softener settings only.

Capacity setting: why the nameplate number is wrong

The C value is the step most set-ups get wrong. The control divides C by H to get the gallons it lets through, so a capacity your salt dose can’t deliver means hard water before the valve regenerates. The name “48,000-grain” is a maximum-salt figure, as our guide to what water softener grain capacity means shows with makers’ own tables.

Pentair’s performance data sheet for its 5600SXT systems makes the point with its own numbers. The 1.5 ft³, 10 x 54 system (VT-17-01) is rated at:

So the same tank can be anything from 17,900 to 53,100 grains, and “48,000” is only reached somewhere above 9 lb per ft³. Pentair doesn’t publish a 6 lb per ft³ figure. For that dose we use the design table in Water Conditioning & Purification magazine: about 21,000 grains per ft³ at 6 lb, 26,000 at 9 lb, 29,000 at 12 lb and 31,000 at 15 lb. Those are more conservative than Pentair’s lab ratings (Pentair’s sheet gives about 31,000 per ft³ at 9 lb), which is the safe side to err on when the number sets your regeneration trigger.

Worked out for common tanks at 6 lb per ft³:

If you’d rather run a higher dose, use the matching row and a longer brine fill. What matters is that C and the fill time describe the same dose. Our water softener running cost calculator shows what each dose costs in salt over a year.

Hardness and reserve

Enter H as grains per gallon. The Fleck manual gives no allowance for iron, so use your softener maker’s figure or a common one: the Whirlpool and WaterBoss manuals add 5 gpg per 1 ppm of clear-water iron, Hellenbrand’s adds 3. The full list with sources is in our guide to the water softener hardness setting. With 15 gpg and 1 ppm iron at 5 per ppm, you’d enter 20. You can change H later without master programming: user programming (hold Up and Down for five seconds with the clock not at 12:01 PM) steps through DO, RT, H, the reserve and CD.

The reserve covers the gap between the moment the count reaches zero and the regeneration time. The manual gives two ways to set it:

• SF, safety factor: a percentage of the calculated capacity, 0 to 50%. It moves automatically when you change C or H.
• RC, fixed reserve: a set number of gallons, no more than half the calculated capacity. It stays put when C or H change. The manual lists RC as the default.

The manual says a meter delayed control needs a reserve big enough to keep treated water flowing until regeneration time, and that a meter immediate control generally needs none. It doesn’t give a number. Our reasoning: in the worst case the count runs out just after the nightly regeneration time, so you need close to one day’s water. At 31,500 grains and 20 gpg, the valve counts 1,575 gallons; a household using 300 gallons a day would set RC to 300, or SF to about 19%. You can read the reserve the control is actually holding in diagnostic mode (hold Up and Extra Cycle for five seconds, then press Up until RC shows).

Calculator

Check the capacity and hardness for your water

People in the home

people

Water use per person per day

gal

Hardness

gpg

Dissolved (clear-water) iron

ppm

Manganese

ppm

Grains to add per 1 ppm iron5 (Whirlpool and WaterBoss manuals)4 (Nelsen)3 (Hellenbrand H125 manual)

Days between regenerations

days

Salt setting6 lb per ft³, about 21,000 grains per ft³ (efficient)9 lb per ft³, about 26,000 grains per ft³12 lb per ft³, about 29,000 grains per ft³15 lb per ft³, about 31,000 grains per ft³ (maximum)

4 more inputs +

Resin to buy

1.5

ft³

Compensated hardness

15.0

gpg

Hardness removed per day

4,500

grains

Salt setting

6

lb per ft³

Resin capacity at this setting

21,000

grains per ft³

Resin needed (exact)

1.50

ft³

Sold as about

48,000

grains

Salt per regeneration

9.0

lb

Days between regenerations at this size

7.0

days

Salt per month

39

lb

Conservative continuous flow

7.5

gpm

How this works →

Regeneration cycle times and brine fill

A downflow single backwash valve runs four steps, in this order per the manual: backwash (BW), brine draw and slow rinse (BD), rapid rinse (RR) and brine tank fill (BF). Each takes 0 to 199 minutes, and 0 skips it. Neither Pentair manual publishes default times, so we don’t give numbers for BW, BD or RR: keep what your dealer set and write it down before you change anything. The manual’s start-up procedure gives a check instead: in backwash the drain should run steady for about 10 minutes or until clear, and in rapid rinse for about 5 minutes or until clear.

Brine fill is different, because it sets your salt dose and you can calculate it. The parts list gives each brine line flow control with its rate in water and in salt:

Fill time in minutes is the pounds of salt you want divided by the salt rate. For 1.5 ft³ at 6 lb per ft³ (9 lb): 6 minutes with a 0.50 gpm BLFC, 12 minutes with a 0.25 gpm one. For Pentair’s 13.5 lb row: 9 minutes at 0.50 gpm. The manual’s own parts list shows both a 0.50 gpm washer and a “1 gpm, 3 lbs salt/min” label on the injector assembly, so don’t assume: read the size on your BLFC before you set BF.

Two more checks on the hardware. The injector is sized by tank diameter: #1 (white) for 9 and 10 in tanks, #0 (red) for 8 in, #2 (blue) for 12 in. And the drain line flow control should suit the tank; Pentair’s 10 x 54 system backwashes at 2.4 gpm, and a 2.4 gpm flow washer (12088) is in the manual’s parts list.

Manual regeneration and resetting the time

• Regenerate now: hold Extra Cycle for five seconds while in service. The valve goes to step 1 (backwash). Each further press skips to the next step (brine draw, rapid rinse, brine refill, then service).
• Regenerate tonight: press Extra Cycle once. The service icon flashes to show a regeneration is queued for the RT time. Press again to cancel.
• Set the clock: hold Up or Down until TD shows, adjust, press Extra Cycle.
• After a power cut: the control keeps time for at least 8 hours and stores settings indefinitely. A flashing clock means the power failed; press any button, and reset the time if it’s wrong. A regeneration missed in an outage runs at the next RT, usually a day late.
• Resets: a soft reset (hold Extra Cycle and Down for 25 seconds) returns all settings to defaults except the volume remaining. A master reset (hold Extra Cycle while plugging the unit in) clears everything. After either, go through master programming again.

If it’s not softening after programming

Start with the numbers. Check that the volume remaining equals C divided by H minus the reserve, that H includes the iron allowance, and that BF matches the salt C assumes. The manual’s error code 2 means no regeneration for more than 99 days: it tells you to check that the flow indicator flashes when water runs, that the meter cable is connected, and that FM matches the meter.

The manual’s troubleshooting table then lists the hardware causes:

• Hard water: bypass open, no salt, plugged injector screen, or too little water going into the brine tank (check the fill time and clean the BLFC).
• Softener fails to draw brine: plugged drain line flow control, injector or injector screen, or line pressure under 20 psi.
• Uses too much salt: “improper salt setting”, meaning BF is longer than your dose needs.
• Iron in the softened water: fouled resin. The manual suggests checking backwash, brine draw and fill, regenerating more often and lengthening backwash.

If your well has more iron than a softener handles well, programming won’t fix it; our guide to choosing between an iron filter and a water softener covers the limits. And if you’re still choosing a system, our best water softeners for well water lists resin volume and capacity at efficient salt for each pick, so the numbers above are easy to fill in from day one. Our Fleck 5600SXT review covers the valve and the AFW 48k build, and Fleck 5600SXT vs 5800SXT vs Clack WS1 compares it with the larger valves. More softener guides are on the water softeners hub.