New softener runs out of gas early - Fleck 7000SXT settings?

[ChrisBeall]

10" x 54" resin tank
16 lbs gravel
1.5 cu ft CR10 resin
Fleck 7000SXT valve
18" x 33" round brine tank

Incoming hardness 20 - 21 gpg. 2 adults in household. Community water supply with good pressure.

Issue: the softener seems to gradually fall behind. Today I measured hardness of 10 gpg with 100 gal capacity remaining (plus 150 gal reserve). I'm looking for the opposite, where each regeneration recovers more of the capacity than has typically been used since the last regeneration.

Current settings, most of which are as recommended by the vendor:
DF GAL
vT dF2b
CT Fd
C 30 (unit was sold as 48K capacity and that was the initial setting, but my reading here advised using only partial capacity as a tradeoff to save salt, so I've done that)
H 20
RS rc
RC 150
DD 30 (unlikely to ever be reached unless we're away for an extended time, in which case I'd probably shut everything down)
RT 2:00
B1 10 First backwash
BD 60 Brine draw (observation shows that the check valve shuts off actual draw from the brine tank after about 20 - 25 minutes)
B2 5 Second backwash [vendor had recommended 10; but I think this is the setting the valve came with; I don't recall changing it.]
RR 10 Rapid rinse
BF 12 Brine fill (which I figure equals 3 gal = 9 lbs salt = 36,000 typical grains of hardness) [vendor had recommended 10 and 'actual setting varies depending on system size'.]
FM t1.2

Everything on the softener seems to be working correctly, except the result. Does anyone see issues with these settings? If you have recommendations, I'd appreciate knowing how you derived them, as I always like to have some idea of why I'm changing something.

 

[Reach4]

BF 12 Brine fill (which I figure equals 3 gal = 9 lbs salt = 36,000 typical grains of hardness) [vendor had recommended 10 and 'actual setting varies depending on system size'.]

You need to know the BLFC value. You are presuming 0.25 GPM. Many have a 0.125 BLFC. You can look, or you can measure the water that is being put out during the brine fill stage.

 

[Sponsor]

 

[JRC3]

The sticker on the back of the valve should have that info. I would still pull the BLFC and look as well as measure it's output.

 

[Bannerman]

If your BLFC value is actually 0.25 gpm, then your BF=12 for a 9 lb salt setting is correct. That salt setting is adequate to restore 30k grains usable capacity, not 36K as you had specified.

You indicated your hardness tested at 20-21 grains hardness but you programmed only 20. As you seem to be implying some variance, it is recommended to add 1 or 2 grains to the highest hardness amount tested, in case the hardness fluctuates even higher. (ie: H = 22 or 23).

Since you had stated the 'C' setting was originally programmed as 48K, I expect the softener's total capacity will then have been exhausted prior to each regeneration. The amount of salt required to restore all 48K would be 27 lbs each regeneration which I expect had not been programmed. Although the usable capacity has now been reduced to 30K, the total capacity will need to be restored to prevent hardness leakage as the unit nears regeneration. This is achieved by regenerating 1X with 27 lbs of salt.

As you anticipate there is brine prepared containing 9 lbs/salt for the next regeneration cycle, you could simply add 6 additional gallons of water to the brine tank (with a bucket), wait 2 hours for additional salt to dissolve, then initiate a manual regeneration cycle. As soft water will not be provided while regeneration occurs, the manual regen cycle could be initiated just before bedtime. If the brine tank will not hold 6 more gallons, you may need to perform 2 manual regen cycles back-to-back (2 hours between) using 1/2 of the high salt dose for each.

 

[ditttohead]

Hardness is always adjusted higher than actual. "Compensated" hardness is typically no less than +10% to accommodate competing ions that do not show up in hardness testing. Higher than 30 would require a higher compensation %.

 

[ChrisBeall]

You need to know the BLFC value. You are presuming 0.25 GPM. Many have a 0.125 BLFC. You can look, or you can measure the water that is being put out during the brine fill stage.

Um, yes, well that could be an issue. I WAS assuming (or, for some more substantial reason, believed) that the BLFC was .25 gpm. Examination of the sticker on the back of the valve says it is .125, so all of my calculations are way off. Examination of the actual restriction disk shows 3 markings: F 39 123. Yes, that last digit is a three, not a five, so this seems to be a secret code rather than an actual specification. Still, I'll recompute things using .125.

 

[ChrisBeall]

Hardness is always adjusted higher than actual. "Compensated" hardness is typically no less than +10% to accommodate competing ions that do not show up in hardness testing. Higher than 30 would require a higher compensation %.

Odd. In all the reading I did, I never came across 'compensated hardness' before. My water company does not report either iron or manganese content. Many years ago we had serious issues with iron, but something changed and I've seen no evidence of it since. So I'll go with a 1.1 multiplier and change hardness to 22 gpg. (When I initially called the water company, they said, "We usually tell people to use 17 gpg when sizing a system", but their annual report shows the 4 well sources as having hardness of: 13, 17, 18, 19.) Alternative facts...

 

[Reach4]

See #2 on https://terrylove.com/forums/index.php?threads/programming-a-fleck-7000-and-sanitizing.47960/
You might also check the injector color as suggested in that post.

This picture is from that post:

 

[ChrisBeall]

If your BLFC value is actually 0.25 gpm, then your BF=12 for a 9 lb salt setting is correct. That salt setting is adequate to restore 30k grains usable capacity, not 36K as you had specified.

I have a question on this. Somewhere I read that 1 lb of salt can remove 6000 grains of hardness under ideal theoretical conditions, but that 4000 was a more realistic number in practice. You're using 3333. Why? I've continued to use 4000 in the calculations below, but I think there's enough slop in them that either number will work.

Now, my action plan:

• Change H from 20 to 22 (fudge factor for 'compensated hardness).
  
• Change BF from 12 to 24 (adjust for BLFC .125 rather than .25) 24 min * .125 gpm = 3 gallons * 3 lb/gal salt = 9 lbs salt * 4000 grains removed per lb = 36,000 grains per regeneration. [or 30,000 if 3333 gr / lb is more correct; in any case C is already 30]. BD of 60 should still be adequate to pull out all of the brine.
• The system regenerated last night with the old settings (which, using the new data for BLFC, should have restored 18,000 grains of capacity, so add 2 gallons of water to the brine tank now (total 3.5 gal, yielding 10.5 lbs of salt and 42,000 grains of capacity) and regenerate again overnight to regain full capacity as a starting point. (This totals 60,000 of capacity regenerated over 2 days, ignoring usage during the day today and the fact that total capacity is 48,000).
• Check hardness as the 7000SXT balance reaches ~ 100 gal and verify that hardness is absent.
• Send thanks to the folks who provide such a valuable service here.

Lessons learned:

• Triple check everything, especially beliefs about BLFC value.
• If the system falls behind enough that all capacity is exhausted before a regeneration, a one-time full (extra salt as required) regeneration is necessary to recover and try again with new, more aggressive, settings.

 

[Reach4]

BD of 60 should still be adequate to pull out all of the brine.

BD should pull the brine in the first 1/4 of the cycle, and the remainder serves as the "slow rinse". Click Inbox.

 

[ChrisBeall]

See #2 on https://terrylove.com/forums/index.php?threads/programming-a-fleck-7000-and-sanitizing.47960/
You might also check the injector color as suggested in that post.

Violet, which agrees with the label value of '00'.

 

[ChrisBeall]

BD should pull the brine in the first 1/4 of the cycle, and the remainder serves as the "slow rinse". Click Inbox.

OK, I read the Inbox suggestions, which created more questions in my mind, most of which are for my general education:
1. You suggest BD = 32 if the injector is violet (which it is). How did you arrive at that? What is the significance of the various injector sizes? BLFC limits the draw rate, so I would think you would want in injector that can pull at that rate or a little more.
2. You suggest changing to a variable reserve, which has some attraction for me, since our usage can vary considerably. CR defaults to zero, which the Fleck manual defines as 'changes the reserve based on the previous day's (singular) water usage', going down 10% if usage dropped from the prior day and up to the current day value if it was greater than the day before. I infer that this calculation is done once every day, perhaps at midnight. What other values of CR are possible and what algorithm do they use [it's not in the Service Manual I have]?
3. You suggest changing B1 from 10 to 8. How did you arrive at that?
4. You suggest changing RR from 10 to 5. How did you arrive at that?

And a more general question for the group. If all of the input variables are known, is there general consensus on the correct settings to use for: full regeneration, max salt efficiency, max water efficiency, max salt plus water efficiency (which would require cost-per-unit as inputs), i.e. could all of this be put into a computer program that removes the uncertainty and displays the path it used to generate the results? The alternative, it seems to me, would be witchcraft.

 

[ditttohead]

Capacity removed is based on industry accepted standards. It is a very complex and almost incalculable equation since every possible variable could never be truly known. It would be like giving an absolute MPG on a car. Altitude, road conditions, air temperature, humidity, tire air pressure etc all play major factors in the actual performance vs. the "rating." We use industry standards to hopefully ensure consistent high quality water rather than absolute maximum potential efficiencies. The difference is typically less than a single bag of salt per year but having nearly perfect soft water all the time is worth the $4.50.

All that being said, higher salt setting produce lower efficiencies but higher quality water. A setting of 3000 grains per pound of salt at 8#'s per cf tends to give an excellent balance of quality and efficiency.

123 is .125 GPM.


Set the unit as follows
DF GAL
vT dF2b
CT Fd
C 36
H 22
RS cr
DO 30
RT 2:00
B1 6
BD 80
B2 3
RR 6
BF 32

This should work very well for you. Be sure to add a few gallons of water to the brine tank and do a manual regeneration.

 

[ChrisBeall]

BD should pull the brine in the first 1/4 of the cycle, and the remainder serves as the "slow rinse". Click Inbox.

As far as I know, the only way to determine this is to sit and watch it during a regeneration, noting when the air check cuts off brine pull. Correct?

 

[ditttohead]

And a more general question for the group. If all of the input variables are known, is there general consensus on the correct settings to use for: full regeneration, max salt efficiency, max water efficiency, max salt plus water efficiency (which would require cost-per-unit as inputs), i.e. could all of this be put into a computer program that removes the uncertainty and displays the path it used to generate the results? The alternative, it seems to me, would be witchcraft.[/QUOTE]

The math is simple, the potential variables (literally innumerable) can only be assumed. As a system designer, we can only guess as to what the variables may be. Generic settings are done so the unit will work in 99% of applications. The long backwash will work ell for water with iron and sediment but is unnecessary on good clean water sources. In many commercial applications the backwash is completely eliminated without any problems for years but this small amount of water is not an issue in most applications. Same for the fast rinse, it is a cycle that has little importance in most applications. Many companies offer ultra high efficiency systems but by introducing a very small amount of waste the vast majority of problems, headaches etc. disappear.

 

[ditttohead]

It is a simple calculation. The est. brine draw for a 00 injector is approx. .19 GPM. if you set the fill to 32 minutes = 4 gallons of water
4/.19 = 21 minutes. Give or take a couple minutes.

 

[Reach4]

1. You suggest BD = 32 if the injector is violet (which it is). How did you arrive at that? What is the significance of the various injector sizes?

I meant to type 82. Typo. Really.
Violet injector I figured draws 0.17 GPM aprox. When you add brine fill water, you get a little more volume in brine than you add as water (factor of 1.15). I figured it would take about 20.375 minutes to draw the brine. Four times that is 81.5. Round up to 82. Dittohead probably has better numbers. I interpolated from the graph in the manual, and presumed a certain water pressure.
I am computing to more digits than makes sense, I know.

Dittohead's 0.19 probably is pre-adjusted to compensate for water making more brine factor.

 

[ditttohead]

Nah, just a guess from memory... honestly I didnt even look at the chart, just numbers in my head, I knew it was fairly close...

The brine and slow rinse should be 20/40 to 20/60 minutes. Again, just approximations with too many factors so we tend to add the extra time to prevent the wonderful whoops of salty water.

You may notice that every sentence I write is almost always filled with non absolutes. We call them Hillaryisms. Never say anything as an absolute so that way you can disclaim it later..

 

[Bannerman]

, but that 4000 was a more realistic number in practice. You're using 3333. Why?

Salt efficiency does not occur at a constant rate but is highly conditional on the amount of usable capacity programmed vs total capacity. For example, for your 1.5 cuft system:

48K grains total capacity (when resin is manufactured) would require 27 lbs salt to regenerate = 1,778 grains/lb maximum efficiency
45K grains programmed capacity would require 22.5 lbs salt = 2,000 grains/lb max
40,500 grains programmed - 15 lbs salt = 2,700 grains/lb max
36K grains programmed - 12 lbs salt = 3,000 grains/lb max
30K grains programmed - 9 lbs salt = 3,333 grains/lb max

Higher salt efficiency could be realized but would require further reducing the programmed capacity in addition to the salt dose. As capacity is reduced between regeneration cycles, regeneration would occur more frequently, consuming virtually the same amount of water each regeneration cycle regardless of the salt dose.

As Ditttohead stated, higher salt efficiency will come at the expense of water quality so the 30K/9 lb setting is the usual lowest salt dose recommended, but the 36K/12 lb setting would provide higher quality at only a modest efficiency reduction.

48K capacity is not realistically achievable as some resin beads will typically be fractured in manufacturing and handling and some beads will wear over time and so will be flushed to drain. In anticipation of these losses, a 1.5 cuft softener is usually considered to have a total capacity of 45K grains throughout its lifespan.

Since no one can be certain of how much resin loss has already occurred, I usually specify after capacity has been exhausted, to use 27 lbs salt to ensure all capacity is regenerated when the softener is relatively new whereas if older, then 22.5 lbs should be adequate.

 

[Reach4]

have a question on this. Somewhere I read that 1 lb of salt can remove 6000 grains of hardness under ideal theoretical conditions, but that 4000 was a more realistic number in practice. You're using 3333.

For more info on salt efficiency, see #20 in https://terrylove.com/forums/index....ener-settings-salt-brine-grid-question.49333/ including the graph.

Your softener is nicely sized. That is relevant to allowing you to use an efficient salt dose, in a subtle way. For an undersized softener, gaining capacity with higher dosing might get an extra day between regens. If that was 3 days vs 4 days, that is more significant than 8 vs 9 days.